July 1997 Gasification Archive

For more information to help people develop better stoves for cooking with biomass fuels in developing regions, please see our web site: http://www.bioenergylists.org

From jflores at prolena.sdnhon.org.hn Tue Jul 1 00:50:19 1997
From: jflores at prolena.sdnhon.org.hn (by way of larcon@sni.net Ronal W. Larson)
Date: Tue Aug 31 21:35:24 2004
Subject: Plancha Stove (J. Flores)
Message-ID: <v01540b03afdde5477f5b@[204.133.251.9]>

Stovers: This again was directed (today) to "stoves-owner" rather than
to "stoves". This time I have inserted a few questions as well as I have
redirected Juan's answers. Ron Larson

!!Fecha envio: Fri, 27 Jun 1997 22:12:31 GMT
!!A: stoves@crest.org
!!De: Rogerio Carneiro de Miranda <rmiranda@sdnnic.org.ni>
!!Asunto: Re: Plancha Stove on the web site.
!!Enviar resp a: stoves@crest.org

!!RWL> wrote:
!!>
!!> Rogerio: You clearly have a much improved stove over the stove you
!!>are replacing.
!!>
!!> I think it is possible to modify a two-can stove to slide the lower
!!>(fuel - pyrolyzing) can in at the lowest level. The upper combustion "can"
!!>would then be the built in the adobe firebox structure where you are now
!!>combusting the wood.
!!> I think the main difficulty will be finding a way to cleanly
!!>"snuff" the pyrolysis when the pyrolysis is complete.
!!> My hope would be that your users would find it more convenient
!!>because they could better control the power level. What can you say about
!!>the present ability to get and keep a specific power level?
!!> I think the cost could go down a bit, because you would not have
!!>the cost of a door.
!!>
!!RCM> Ron, what 2-can stove are you mentioning ? Could you refresh my
!!memory about it? Is that like your charcoal making stove ?
!!
!!
!!RWL> Approximately what length of cooking time should one strive for in
!!>Nicaragua ? 40 to 60 minutes
!! How many kg wood per hour are presently consumed? ?????????????
!!Is there a big difference between the desirable maximum (to achieve a rapid
!!boil) and
!!>minimum rates of consumption? ???????????????
!!Is this achieved by control of the door opening? also, but mostly the women
!!traditinaly uses more or less wood to achieve higher energy outputs.

JCF> The consumption with the plancha stove is about 20%
less than in the non-improved woodstove, and the consuption per day
is 65.64 Kg. The people use the woodstove about 10-12 hors per day,
the time use depend in the work of the people. For exempla if the
person make "tortillas" (a kind of food that is made of corn) they
use the woodtove about 12 hours per day. The rates of consumption are
from 93 Kg/week to 39.5 Kg/week. The different is big because there
aren't a stadistic control, so in some cause the woman cook for more
than 6 person and she has to make torillas. The women that make
tortillas make more than 1200 tortillas per day, and they have to
cook all the day. In another case the people don't have the enough
education for using the woodstove, and they don't use the woodstove
in the right way. This is a very important point, because if we want
the people use the improved woodstove, we have to training them, and
to explain them Why they have to use the new woodstove.

(RWL): Juan - the numbers above are inconsistent. Your "daily" number
"65.64" is about midway between the "weekly numbers" "93" and "39.5". Is
it possible that all numbers should be kg/week?

If so, might we say that the daily rate is about 10 kg (+/- about
3.5 kg)?

And a typical (maybe also maximum) hourly rate might be about 1 kg
? (This is about 5 kW.)

!!RCM> We should further consulte with Juan Carlos Flores. he is the director
!!of this project in Honduras, and so he can be more accure with this info.
!!Observe that the plancha stove pictures are from the Honduran project that
!!has been running for 2 years now..
!!
!!
!!Juan Carlos> Can you participate in this discussion and please gather and
!!help us with the missing info about the operation of the plancha stove ?
!!
!!
!!Thanks
!!
!!
!!Rogerio
!!--------------------------------------------------------------------------
!!Rogerio Carneiro de Miranda Telefax: (505) 276 0555
!!PROLENA(Nicaragua)
!!Apartado Postal C-321 Managua Nicaragua
!!E-mail: rmiranda@sdnnic.org.ni
!!-------------------------------------------------------------------------
!!
----------------------------------------------------------------------
Juan Carlos Flores Lopez
Director Ejecutivo PROLENA/Honduras
Tel/Fax: (504) 32-0639
P.O.Box 3870 Tegucigalpa, Honduras.
E-Mail: jflores@prolena.sdnhon.org.hn
----------------------------------------------------------------------

And my thanks also to Juan. I hope my insertion was OK. Ron

From larcon at sni.net Tue Jul 1 00:50:28 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:24 2004
Subject: Indexing/threads (Reed and Burt)
Message-ID: <v01540b04afddeb9bfbfb@[204.133.251.9]>

Stovers:

1. In response to a list of 13 possible threads introduced by Tom Reed
yesterday (June 29):

I. TECHNICAL:
A. Primative wood stoves (three stone etc.)
B. Classical improved wood stoves (swosthee etc.)
C. Wood-gas stoves
D. Charcoal stoves
E. Methods of testing
F. Methods of making and manufacturing

II. SOCIAL:
A. Biomass supply
B. charcoal
C. health
D. Cooking
E. Acceptance of new stove technology
F. Stove costs
G. Stove construction fitted to particular countries

Brian Burt said yesterday:

>This is a very useful list. Perhaps a list of outstanding threads
>(questions), could be maintained by Ron (you know ask a busy person) or on
>the Stove page.

)RWL): This is my response to Brian's invitation. I will at least
keep a record of what people are using (and I haven't had a chance to go
back for that purpose yet).

2. About 6 months ago, I exchanged some off-list messages with list
members Sam Baldwin and Tom Ferguson that were on this topic. This was
heading toward a possible web page for the US National Renewable Energy
Laboratory (NREL). But just about then Sam was temporarily assigned to the
White House and we went into a holding mode. Tom and I decided today that
Sam would not object to trying out that (following, but modified) list. I
have added or identified those closest to Tom's list of 13 using the
symbols I.A, I.B, etc.

3. I suggest that we just start using the list, and after a month,
I will raise the "thread" subject again and we can move toward
standardizing if that seem appropriate. Feel free to add or modify. (The
word "thread" might be replaced by "indexing" for instance - depending on
what people use over the next month)

4. I have been putting the name of earlier contributors to the
thread in my titles (in this case "Reed and Burt").
I also have been changing the names sometimes when they didn't seem
pertinent. (For instance in this response I dropped "Beedie Gasifier"). In
other words - don't necessarily use the name that came in?
Are these extra "rules" helpful?

5. The Baldwin-Ferguson-Larson list:

a) energy loss mechanisms
conduction
convection
radiation
incomplete combustion

b) stove design principles
materials choices
max power levels
turn-down ratio
frequency of re-fueling
fuel piece type and size
chimney theory and design

c) Design and manufacture trade-offs (IF), IIE
indoor vs. outdoor cooking
type of fuel (wood, charcoal, agricultural wastes, fossil fuels) (II.A)
location of manufacture (imports, urban assembly, rural assembly)
efficiency
ease of use
costs (first and life cycle) IIF
importance of lighting
cooking type (frying, boiling, water purification, etc.) (II.D)
degree of innovation (new vs extension of existing practices)

d) Combustion fundamentals
pollution products
local
global
health impacts (IIC)
influence of water content

e) Pyrolysis and gasification fundamentals (charcoal production) (IIB)

f) Stove case studies II.G
A. Primitive wood stoves (three stone etc.)
B. Classical improved wood stoves (swosthee etc.)
C. Wood-gas stoves (charcoal-making stoves)
D. Charcoal stoves

user rapid appraisal questions
user profiles (income levels, transiency)
environmental variables (temperature, rainfall, etc)
design case histories
marketing description
existing costs of fuels and/or times for collection
uses of release time

g) product specifics
testing (I.E)
specifications

h) government promotional opportunities and experiences
infrastructure development
RD&D support
taxes
financing opportunities

i) sources of funds

j) corporate, University, and other links to specific products

k) similar products
fuel production
heating stoves
industrial scale cook stoves

l) country-by-country per capita consumption statistics

m) additional sources of information
on-line discussion groups
Web sites
Photograph collections
University courses
books
competitions
multi-lateral and bi-lateralinformation programs
journal articles
software
Technical resources
partner laboratories
news items
calendars
index and key-word search ("Threads")

A. Constraints - this list of topics is based on a feeling that the
present stove list emphases are on:
1) system (from fuels to wastes) perspectives of stoves
2) developing countries.
3) comparisons between stove designs

B. Numerical data is to be emphasized especially for:
a) efficiency and fuel consumption,
b) pollution and health impacts,
c) first and life-cycle costs, and
d) ease of use and other user subjective factors

C. This site is not:
1) a place to find a specific stove recommendation (but data will
be available to come to better decisions)
2) a source of funds (but all known sources will be provided)
3) a promoter or endorser of specific products (but links will be
made to corporate sites; addresses will be given and product types of
sopecific manufacturers will not be promoted - but other (e.g Web) sources
of information will be encouraged.)
4) a static, unchanging site (but rather will be regularly changing)
5) a WEB SITE (such as is that of Alex English, Paul Hait, etc)

6. Other: I believe Tom Reed was looking for a list for saving messages.
The above may be too lengthy for that purpose. However, some people may
choose to emphasize different aspects of the same paper - so a note might
be 1) testing (not design of) of 2) different fuels (not moisture content
or a single fuel, e.g straw) with a 3) charcoal-making stove (not a 3-stone
fire or charcoal-using stove) and three different people would file it
three different ways - and all still be happy.
Eventually our (crest?) data base system will list all three words
and we will pick out all those messages with just those characteristics -
no matter where it is filed.

7. Brian: Was this is somewhat like what you were looking for? Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Tue Jul 1 00:50:16 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:24 2004
Subject: 2can Turbo mk2 - Trial 1 results
Message-ID: <v01540b00afddd2530b50@[204.133.251.9]>

Elsen said today:

>Negative. Heap big smoke, little flame. Red eyes.

(RWL): Sorry to hear it, but plenty of ways to fix this I'll bet.

<snip>

> The larger upper can
>projecting 5 cm below the ring acting as a wind shield, and the smaller can
>projecting 5 cm above the ring into the combustion chamber, with the lip
>notched & twisted to provide turbulance.

(RWL): Could you describe this notching and twisting a bit more.

(Elsen):
>This arrangement introduces the secondary air vertically through the
>drilled holes in the connecting ring into the combustion chamber away from
>the pyrolisis gasses behind the baffled 5 cm high lip of the lower can.

(RWL): I don't understand the word "baffled" in the last line. Is this
the same as notching and twisting?

<snip>

(Elsen):
>As the present secondary air arrangement seems to be of no benefit, I'll
>close the air holes in the connecting ring and drill them through the wall
>of the pyrolisis chamber at the level of the ring. This will introduce the
>secondary air horizontally 5cm below the top baffled lip of the lower
>(smaller) can in order to test if turbulance AFTER the introduction of cool
>secondary air aids combustion and controllability, as opposed to BEFORE.

<snip>

(RWL): 1. Have you already done the "BEFORE" test or is this still to
come? I think this is a question of where the flamelets hold. I think
they will hold at your (roughly) 48 4 mm holes and not 5 cm up at the
"twists".

2. Tom Reed pointed out recently that the way to get blue short flames was
through pre-mixing. Given this, the issue may be whether turbulence occurs
before or after the flame holds somewhere.

3. Assuming I may get to you before you close the 48 vertical holes, it
might be interesting to try one other test first. I'd like to see if you
can get a lot of gas out to the radius of these secondary air holes. I'm
thinking of a large disk of maybe the same diameter as the secondary air
holes (about 25 cm?). This disk can possibly just sit on the smaller
cylinder - because you have the notching and twisting to let the pyrolysis
gases escape.
It will probably be only possible to place this new horizontal disk
after you have well started the downward travelling pyrolysis zone in the
smaller can. There may be too much resistance - but you have a pretty good
chimney height.

Good luck. Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From ovencrft at nbn.com Tue Jul 1 02:14:09 1997
From: ovencrft at nbn.com (Alan Scott)
Date: Tue Aug 31 21:35:24 2004
Subject: Calling some hardcore stovers...
Message-ID: <199707010614.XAA17950@moon.nbn.com>

>Hi.
>
>Yesterday, on Nat. Public Radio, an interview on "The Splendid Table" featured
>the author of the book "License to Grill". He (can't recall last name,first na
>me John, nickname "Doc") said that lump hardwood charcoal (in Argentina we used
>to call it carbon de len~a), is finding its way into gourmet places for use in
>grills, slowly replacing briquettes.
>Is this a trend any of you are aware of? Implications?
>
>Demetrio.
>
>
Yes, I build wood fired bake ovens occaisionally for "high end" restaurants
and they all have solid fuel grills and this usually means Mesquite
charcoal, is this what you mean by "hardwod" charcoal.
ALAN SCOTT
ALAN SCOTT

Check out the new web site for OVENCRAFTERS
http://pomo.nbn.com/home/ovncraft

From elk at arcc.or.ke Tue Jul 1 06:38:48 1997
From: elk at arcc.or.ke (E. L. Karstad)
Date: Tue Aug 31 21:35:24 2004
Subject: Kenya Ceramic Jiko
Message-ID: <v01510100afde7ebefea4@[199.2.222.133]>

Mike Bess writes:

>I am proud to say I was there to watch the
>Kenya Ceramic Jiko (KCJ) being conceived and born, and I am sad to say
>that the parents (to follow the analogy) left it as an orphan and went
>on to other things. That's to say, a million KCJs later and no-one I
>know of can tell you whether they save energy or not, whether they last
>one year, two, etc. because no government interest or involvement, ditto
>on donors, and the jiko producers, well, they're great businessmen, and
>they just produce.

Mike;

I'm one owner- I use a KCJ on safari.

Questions to my staff reveal the following:

1) 20 cm internal dia. KCJ retails at ~$ 3.30 and lasts for 7 to 9 months.

2) 35 cm @ ~$6.40 & probably lasts a couple months longer.

3) standard metal jiko with door costs ~$2.20 and can last up to 1 year.

4) estimates on savings in charcoal use range from 50 to 60%

5) Charcoal use increases relative to kerosene during the ~4 cold months in
Nairobi. Ratio not known.

6) Estimates of KCJ users in & around Nairobi is between 30 to 40% of
domestic charcoal users.

7) Not much use of KCJ in rural areas- primarily wood fuel used & no known
improved wood stoves are available in the market.

_____________________________
Elsen Karstad
P.O Box 24371 Nairobi, Kenya
Tel:254 2 884437
E-mail: elk@arcc.or.ke
______________________________

From E.Moerman at stud.tue.nl Tue Jul 1 07:26:56 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:24 2004
Subject: 'elk works' on the web
Message-ID: <5239.s335192@popserver.tue.nl>

Paul Hait:
> One million years ago man started a very bad habit. He randomly dumped fuel
> into a black hole and burned it at less than 10% efficiency. As a result of

Etienne:
A well tended open fire showed an efficiency in our lab that was around 25%.
Granted that this was under ideal circumstances, but with an indoor open
fire around 20% should be possible. Of course bad husbandry of the fire can
reduce the efficiency to any low number you want.

Paul Hait:
> the answer. Stovers need to unit Worldwide under one banner with a
> foundation that has as its sole goal to communicate the simplest and most
> efficient answers to solving this problem. In short we need to set up a fund
> to communicate the urgency of the problem and then deseminate official
> design and performance data to those countries that have the biggest needs.

Etienne:
An organization like this already exists for about 10 years. It is called
the Foundation for Woodstove Development (FWD) and it is based in Kenya.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Tue Jul 1 07:27:03 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:24 2004
Subject: NATURAL CONVECTION AIR GAPS
Message-ID: <5248.s335192@popserver.tue.nl>

Tom Reed:

> convection combustion - lots of trial and error. Etienne has said that
> they favored a 5-6 mm gap for secondary air inlet. I said that we had
> tested a 10 mm gap for both the secondary inlet and the annular ring
> spacing combustion zone. =

> if it is more than 6 convection cells can develop to increase loss. It
> would be interesting to see whether this was determined experimentally or=
> from a theoretical base. =

Etienne:
Both, see Paul Bussmann's thesis.

Tom Reed:
> I have been puzzled by the explosion of experimental work in this group. =
> I
> grumbled a month ago that everyone was talking, no one doing, and now I
> can't keep up with all the work in progress. I can hardly wait to return=
> to my lab to get my oars moving. What has caused this explosion? Good
> weather in the Northern Hemisphere? =

Etienne:
Our experiments were done years ago. In Eindhoven no experiments have been
done for the past 2 year or so. About the wheather I can only say that it
has been very wet for the past month or so.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Tue Jul 1 07:27:04 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:24 2004
Subject: Charcoal yields vs superficial velocity
Message-ID: <5252.s335192@popserver.tue.nl>

Tom Reed:

> Etienne is correct that a conventional downdraft gasifier produces very
> little ash. Let me be a little more specific. It typically gasifies mos=

Etienne:
I was talking about the downdraft stove, not the downdraft gasifier. In the
downdraft stove no "char-ash" is left. After pyrolysis the stove is still
very hot and results in a fast charcoal combustion, due to air supply and
due to temperature.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Tue Jul 1 07:26:58 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:24 2004
Subject: Charcoal and CO
Message-ID: <5235.s335192@popserver.tue.nl>

David, to answer your questions.

> David B.: That's reassuring. I observed the rate of increase of CO
> with time to be very dramatic - much more so than the rate of
> temperature fall - which is qualitatively consistent with the expected
> exponential relationship. Did you also get this effect?
>
>> For high temperatures the production of CO2 is favoured as long as
> there is
>> sufficient O2.

Etienne:
Just as we measured. Also for an excess air factor below 1.2 a sharp
increase in CO/CO2 occurs. It all seems in agreement with the Arrhenius
reaction rate.

>> David B.:
>
> Me too. My control system usually prevented out-of-range values of
> excess air during volatile combustion so this was not seen. Control
> was most critical as fuel 'exhaustion' - i.e. complete carbonisation -
> approached.
>
> Another interesting effect I noticed occasionally in gusty conditions
> was that large CO impulses would come and go equally dramatically.
> Although the cause could not be seen as corresponding changes in the
> measured excess air value, corresponding rapid fluctuations COULD be
> seen in the combustion temperature. This probably showed that there
> really were large excess air value fluctuations which were not seen
> owing to the slower response times of the O2 and CO2 sensors.
>

Etienne:
I am glad that somebody else is observing the sensitivity of the CO/CO2
ratio on excess air factor and combustion temperature in actual stove
experiments.

Our CO, CO2 and O2 measurements lagged behind by 35 to 55 seconds depending
on flow rate through the sample tube. In some sensitive cases I made a
correction for this.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Tue Jul 1 07:27:10 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:24 2004
Subject: Figure of merit
Message-ID: <5255.s335192@popserver.tue.nl>

Tom Reed:

> 3-5 times in power for simmering. So we need a figure of merit that
> emphasizes the ability to control, one of teh star advantages of wood-gas=
> stoves over wood stoves. =

Etienne:
This is what is commonly called the turn down ratio; the ratio between
maximum and minimum power output.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From skip.hayden at cc2smtp.NRCan.gc.ca Tue Jul 1 08:05:57 1997
From: skip.hayden at cc2smtp.NRCan.gc.ca (Skip Hayden)
Date: Tue Aug 31 21:35:24 2004
Subject: Turbulent & diffusion blue flames
Message-ID: <9706018677.AA867769530@cc2smtp.nrcan.gc.ca>

Be careful - blue does not always mean "clean" when that is
defined as unburned or partially burned combustible
material. It only means that there are no particulates.
There still can be high levels of carbon monoxide, depending
on how the combustion process actually occurs.

Skip Hayden
enior Research Scientist
Advanced Combustion Technologies
Ottawa, Canada K1A 1M1
TEL: (613) 996-3186
FAX: (613) 992-9335
e-mail: skip.hayden@cc2smtp.nrcan.gc.ca

From phait at transport.com Tue Jul 1 10:57:45 1997
From: phait at transport.com (John Doe)
Date: Tue Aug 31 21:35:24 2004
Subject: Mike Bess on Charcoal and Stove Characteristics
Message-ID: <199707011452.HAA23497@butch.transport.com>

>Dear Ron,
>
>Wow, I feel like a kid who's just met a lot of new friends! The
>questions are almost overwhelming, but extremely stimulating because
>they are right on the mark, and it is always good to exchange
>information about something you like with new colleagues!
>
>I'll try to answer briefly now. Perhaps the paper I sent will give more
>detail, and we are very pleased to send information to all comers. Let
>me start at the beginning.
>
>Fifteen years living and working with renewable energy in East Africa,
>first on a USAID-World Bank regional project, then with our company
>which is based in the UK, Energy for Sustainable Development. Lots of
>stove projects - too many, and too many failures. Top down, technology
>driven, the whole list. I am proud to say I was there to watch the
>Kenya Ceramic Jiko (KCJ) being conceived and born, and I am sad to say
>that the parents (to follow the analogy) left it as an orphan and went
>on to other things. That's to say, a million KCJs later and no-one I
>know of can tell you whether they save energy or not, whether they last
>one year, two, etc. because no government interest or involvement, ditto
>on donors, and the jiko producers, well, they're great businessmen, and
>they just produce. So, I learned a lot from this experience which ties
>into some of your questions.
>
>First, don't start something like this unless you are willing to follow
>it through, and that means testing, qualilty control, monitoring, etc.
>also, don't just train people up and expect them to know all the details
>of thermo-dynamics, air flow, etc. that make stoves efficient. So,
>don't abandon them after two years (move on to another project and
>another country) and expect them to keep the right design, the right
>number of holes, the right thickness of the metal, etc....
>
>Ethiopia is where we have really helped to nurture the stove activities,
>and tried to apply these, and other, principles. We began work in late-
>1989 with the then Ethiopian Energy Authority, now known as the
>Ethiopian Energy Research and Studies Centre under a DANIDA (Danish) and
>World Bank grant for "cooking efficiency improvement". We had an
>excellent kick off with the help of Willem Floor of the World Bank whose
>ESMAP programme is one of the hottest and best in the world. We drew up
>a needs assessment (860+ household interviews, interviews of over 100
>stove producers and merchants), did our homework on previous Ethiopian
>and East African work, and Willem helped fight off the World Bank's
>civil servants who wanted to stick to the original plan to mass produce
>several hundred thousand high cost combined charcoal and wood stoves.
>
>We had been doing fuel price surveys in Addis Ababa since 1988 and knew
>charcoal was increasing in use. We also knew wood use in the city was
>going down, so, we decided to tackle charcoal first. This is where the
>Lakech improved charcoal stove was born. It was a modified, and
>improveed version of the KCJ. And, 300,000 stoves have been sold since
>1992 when it was introduced. It sells for half the traditional stove,
>and I'm surprised you didn't see more Lakech than traditional stoves.
>The photos Alex is putting on the Web shows my story; we are seeing
>10,000 Lakech being sold every month, and the Mercato, every supermarket
>and most small markets are filled with them. We can go into more detail
>about the pluses and minuses, but we still try to keep the quality
>control, keep providing moulds and templates to producers, TA, etc.
>although we've had no government or donor support on this front since
>1995. Our destructive tests and our water boiling tests on the Lakech
>still show it performing around the 35% mark, which is a 25% improvement
>on the already good traditional Ethiopian metal stove. Also, our market
>and household results show that almost 50% of all Addis households own
>and use a Lakech. The World Bank commissioned an independent survey of
>households as a review of our project (within a much bigger World Bank
>energy project) and found in September of 1994 that one quarter of all
>Addis households had the Lakech (and used it regularly).
>
>The largest, most expensive Lakech now sells for Birr 20 (about US$1.50)
>today, compared to the least expensive traditional charcoal metal stove
>which sells for around EB 14 (about US$ 1). However, 80% of all Lakech
>sell for less than EB 14 (there's been a terrific price war over the
>past year), which makes the Lakech cheaper. By the way, when we
>introduced the stove for market trials in January 1992, the Lakech sold
>for EB 45 (recommended by the biggest producer) to EB 70 (that's when it
>was EB 2 to the US$, not EB 6.5 like it is today). Competition, the
>learning curve, mass production (by skilled artisans) and the stove
>price falls, quality is pretty standard, and 400 are sold every day.
>
>The "traditional" Ethiopian metal stove (there are two main models) is
>one of the more efficient metal stoves made. They average 28-30%
>compared with the traditional Kenyan jiko's performance of 20% or lower.
>High quality craftsmanship has much to do with this. The Lakech liner
>will last one year, perhaps a bit longer, but the stove pays for itself
>within two months of regular use. The liner is replaced as a matter of
>course, and the ceramic shards make great fill for the Addis potholes!
>
>
>Your comments about affordability and market penetration are really
>pretty on the mark for the Mirte ("better") injera cooker, rather than
>the Lakech, for reasons I hope I've explained above.
>
>The Mirte injera stove was a tougher nut to crack, as you are well aware
>having worked in Mekele. And we did hear something about your work in
>Tigray. But, unfortunately we never saw the results (and would like to
>know more). Efforts to improve injera baking have been underway at
>least since the early-80s as groups like the Mennonites (Burayu
>Appropriate Tech Centre) and others tried to improve efficiencies. You
>are right. Half of all energy (not just cooking energy, but all energy)
>consumed in households in Ethiopia goes towards baking injera. You've
>described the baking process right, so I won't repeat.
>
>Enclosing the fire is mandatory, and we and others saw that from the
>earliest days. But, how to do so without getting into the Lorena and
>Bak dilemmas of self-made stoves, quality and performance all over the
>universe....? This was the central problem, and still is, for any high
>mase wood stove.
>
>We were fortunate because we had worked with John Parry of Intermediate
>Technology Workshops (now Parry Workshops) in Kenya and East Africa on
>housing and roofing materials. One of our Ethiopian counterparts
>suggested that perhaps a pre-fab multi-section stove made from moulds,
>using light weight materials might be the answer to developing a low-
>cost energy efficient, marketable stove. Well, two years later (by
>1994) and it was. Again, we can discuss technical details, but the
>stove uses one mould for the four pieces of the main stove, and one
>mould for the chimney rest. It is made by hand (or can be made
>mechanically, as it originally was) and can be assembled and
>disassembled to be moved, transported,etc.
>
>And, it saves energy while it also appeals to cooks because it removes
>the smoke (number one factor), it is clean and modern (number 2 factor),
>it is safe from back flashes from flame (number 3 factor) and it saves
>energy (number 4 factor). These rankings come from over 500 follow up
>interviews from randomly selected households selected from the 17,000
>people we have sales records on.
>
>The Mirte (as with the Lakech before), was tested in actual houehold
>tests in Addis (four sets of tests over a two year period), in Bahr Dar,
>in Awasa. It was cook tested in Gondar, Mekele, Sheshemane,
>Nazareth....and each time, cooks liked it because of the reasons cited.
>I often wonder what the ranking would have been had our enumerators not
>shown up with hats (figuratively speaking) saying "We're interested in
>energy efficiency". Frankly, I believe the ranking would have stayed
>the same and the cooks would not have put saving energy as numero uno!
>
>Two years of this effort from April 1995 to March 1997 were supported by
>the British ODA (now Department for International Development).
>Frankly, a more professional donor would be hard to find. They were
>interested, but let us go on with the technical and commercial work. We
>have four small/micro revolving funds, and 35 active producers,
>employing over 100 people all over the country. In fact, Mirte
>production started in Mekele in January and nearly 1,000 stoves have
>been sold totally commercially, no subsidies, not intermediaries since
>then. We have some of the best women artisans making the stoves in
>Gondar, Bahr Dar and Mekele. Regional and local authorities have been
>totally supportive, and have helped to keep admin and tech costs low
>(they pay us simple per diems, provide ground transport, organise promos
>and demonstrations, etc.). We're now promoting this all on our own, and
>are soliciting corporate sponsorship to expand the Mirte into smaller
>urban areas, and rural areas. It's going that direction anyway. And,
>we don't want to lose control of quality control, training (in basic
>businss and bookkeeping as much as stove quality), technical assistance,
>etc. Promotion is a must for this product, as with any, and we've held
>over 90 public, market demonstrations in seventeen cities and towns
>since September 1995.
>
>A neat feature of the Mirte, which we only discovered as we went along,
>is that it can be fabricated with almost any building materials so long
>as attention is taken to the mix ratio. The Mirte started out with
>pumice and cement (5:1 ratio). Pumice, however, is not found everywhere
>in Ethiopia. So, we tried it with red ash/scoria, another common
>material that is more widely found than pumice. Bingo, same efficienies
>(40% improvement in the lab over traditional injera baking, nearly 50%
>in actual household use). Moving to Tigray and Dire Dawa where no
>scoria or pumice is found, we tried the predominant building materials-
>sand and cement. Again, bingo. The stove performs brilliant. I admit,
>the concept of "portability" is stretched when a six piece stove weighs
>70 kg, but, people build houses with the same materials. They move the
>stove once every three months or so, so, no problem with portability...
>
>The other surprising aspect of the Mirte is that, unless one fools
>around with the dimensions of the fire door or starts putting chimneys
>on the stove, efficiencies stay pretty high and pretty much the same,
>even with a few cracks in the side. It's robust, And, it pays for
>itself after less than 3 months for regular household use (twice a week,
>30 injeras a session, three hours per session), and in less than a week
>if used commercially (ie, for commercial baking - 300 injeras a session,
>every day of the week 365 days per year). The stove sells for about EB
>35 all over the country, with minor variations (we're not into price
>controls). We keep training producers, so competition increases. Some
>producers just move sales out to other towns and villages to keep their
>profit margins which suits our dissemination strategy very well.
>
>Yet, there are lots of things to do, and improvements to be made. But,
>we can talk about that at more length. We believe the proof is in the
>pudding. Without active intervention, meaning no overt subsidies or
>interference in the market place, the stove is selling like hotcakes.
>We realise the "early adopters" are wealthier households and the
>commercial bakers (women heads of household who bake for restaurants,
>hotels, and, increasingly, for wealthier households). However, the
>percolation effect is rapid, and over half of all cumulative sales in
>Addis are to low income households (verified by those 500+ random
>surveys). We need to stimulate the market more through promotion and
>advertising, more people need to be trained, more micro credit needs to
>be available....but we estimate sales will top 30,000 by the end of this
>year. If we get more support for these other things, the sky's the
>limit.
>
>I would like to be able to give you government contacts in Addis, but,
>frankly, the Mirte and the Lakech are really low tech and not much
>interest to the top government civil servants. They have not paid a bit
>of attention to this over the past two years, and are much more
>interested in wind turbines, pvs, and biogas.
>
>Fortunately, our Ethiopian counterparts, headed up by Melessew Shanko,
>(whose email is not working at this moment), but who can be reached by
>telephone on 251 1 613395, or 187398 (fax info later). For the time
>being, we are, I'm afraid, the best contacts for this information, but
>please feel free to get directly in contact with Melessew. By the way,
>our Ethiopian counterparts did up a superb video in Amharic, which sets
>out the design, development, use, training, etc. on the stove, and it is
>sub-titled in English. It's not the highest picture quality, but it
>really puts it all into context, and I can send you a copy once I get
>the chance. I think you'll find it very interesting.
>
>Finally, before passing on the message I sent to Demetrio on charcoal,
>we are continuing to work in Ethiopia, having worked all over the region
>before. We also have a small British grant working with some really
>good practitioners in Kenya, Uganda, Tanzania and Ethiopia to expand
>commercial production of "institutional" stoves - ie, stoves used for
>cooking or baking a lot either for hotels, restaurants and other
>commercial establishments, or for schools, hospitals and the like. We
>have recently completed an extensive study on biomass in Uganda, its use
>and areas for improving its use in households, institutions and small
>industry for the European Commission. We're doing some private
>exploratory work on stoves in South Africa, so, we're pretty active on
>the continent. More on that if you would like.
>
>
>Concerning charcoal prices, here's my message to Demetrio (I don't know
>yet whether what I send to one of the stovers gets passed on to everyone
>else, so please excuse me). Also, I've sent Alex half a dozen photos,
>with info on each for the Web. I see today he has put up two of them.
>Great stuff. Like I began, I feel like a kid whose just found a lot of
>new friends. More later, and thanks for the interesting and provocative
>questions! Ciao! Mike
>
>
>
>Dear Demetrio,
>
>To answer your question briefly, charcoal is cheap (in nominal,
>purchasers' terms) for two reasons. First, there is a lot of
>competition because it is so widely used. So, regardless its
>sustainability, this competition drives down prices. And, you are
>right, labour is relatively inexpensive in most developing countries.
>So, translating shillings or birr or whatever local currency to dollars,
>pounds, etc. makes it look very inexpensive.
>
>Secondly, most charcoal is not sustainably produced (I hope I don't
>sound as if I am contradicting myself here). It is produced primarily
>as a by product of land clearing (which is usually, up to now, a one off
>activity). So, if anything, it has an negative value to the land
>holder, and, indeed, very little, if any, resource cost may be paid. If
>it is produced off public land (which it often is), then the externality
>of using a common good is also not priced - ie, there is no resource
>price. This also drives down the price.
>
>Thirdly, because it often is such an informal sector activity, transport
>is often either informal (lorries or trucks coming back to big cities
>pick up a few bags of charcoal) or illegal. Illegality has a funny way
>of reducing prices, but we can discuss this in more detail if you like.
>
>Whatever the case, our work in Kenya and Uganda shows that charcoal can
>be produced sustainably on a competitive basis with charcoal produced on
>a non-sustainable basis because of modern organisation, higher yields,
>closer proximity to markets,etc.
>
>With regard to better charcoal or better stoves, why not both. If we
>can improve yields and sustainability of charcoal production and end
>use, we really have a very nice sustainable paradigm. We strongly
>promote this in all our work, whether in the developing world or the
>"West". Just a plug or two for sustainability! Hope that answers some
>of your questions, and thanks for the interest. Mike
>
>
>--
>Mike Bess

>Dear Mike, 7/1/97

I have found the above write up to be one of the most brilliant reviews I
have read yet. Congratulations on all your hard work! Please contact me
directly at phait@transport.com. I believe that my HTA Cell principles could
be applied to your cast stoves. Additionally,I have a local company here in
Oregon that has developed a unique light weight fire proof cement like
material that would be great for your stoves. The material could be made in
africa or shipped since it is as light as a feather. When combined with
local materials it sets up into a rock hard material that has extremely high
fire resistance. It is used for fire door material here in the states.
I find your Charcoal facts to be very interesting also. Are there any
Briquette operations in Kenya or Ethiopia? I have found that by arranging
Briquettes in what I call a Harmonic Thermal Array I can get much higher
temperatures quicker with much less fuel( 75% less). I also take advantage
of the the heat radiating down as well as up. Do your Stoves do this? How
can we work together? Check out our site at http://www.estore.com.

I look forward to your email.

Sincerely,

Paul Hait
President
Pyromid Inc
3292 S hwy. 97
Redmond, Oregon 97756
541.548.1041/Fax 541.9231004

From phait at transport.com Tue Jul 1 11:14:47 1997
From: phait at transport.com (John Doe)
Date: Tue Aug 31 21:35:24 2004
Subject: Plancha Stove (J. Flores)
Message-ID: <199707011509.IAA23615@butch.transport.com>

>Stovers: This again was directed (today) to "stoves-owner" rather than
>to "stoves". This time I have inserted a few questions as well as I have
>redirected Juan's answers. Ron Larson
>
>
>!!Fecha envio: Fri, 27 Jun 1997 22:12:31 GMT
>!!A: stoves@crest.org
>!!De: Rogerio Carneiro de Miranda <rmiranda@sdnnic.org.ni>
>!!Asunto: Re: Plancha Stove on the web site.
>!!Enviar resp a: stoves@crest.org
>
>!!RWL> wrote:
>!!>
>!!> Rogerio: You clearly have a much improved stove over the stove you
>!!>are replacing.
>!!>
>!!> I think it is possible to modify a two-can stove to slide the lower
>!!>(fuel - pyrolyzing) can in at the lowest level. The upper combustion "can"
>!!>would then be the built in the adobe firebox structure where you are now
>!!>combusting the wood.
>!!> I think the main difficulty will be finding a way to cleanly
>!!>"snuff" the pyrolysis when the pyrolysis is complete.
>!!> My hope would be that your users would find it more convenient
>!!>because they could better control the power level. What can you say about
>!!>the present ability to get and keep a specific power level?
>!!> I think the cost could go down a bit, because you would not have
>!!>the cost of a door.
>!!>
>!!RCM> Ron, what 2-can stove are you mentioning ? Could you refresh my
>!!memory about it? Is that like your charcoal making stove ?
>!!
>!!
>!!RWL> Approximately what length of cooking time should one strive
for in
>!!>Nicaragua ? 40 to 60 minutes
>!! How many kg wood per hour are presently consumed? ?????????????
>!!Is there a big difference between the desirable maximum (to achieve a rapid
>!!boil) and
>!!>minimum rates of consumption? ???????????????
>!!Is this achieved by control of the door opening? also, but mostly the women
>!!traditinaly uses more or less wood to achieve higher energy outputs.
>
>JCF> The consumption with the plancha stove is about 20%
>less than in the non-improved woodstove, and the consuption per day
>is 65.64 Kg. The people use the woodstove about 10-12 hors per day,
>the time use depend in the work of the people. For exempla if the
>person make "tortillas" (a kind of food that is made of corn) they
>use the woodtove about 12 hours per day. The rates of consumption are
>from 93 Kg/week to 39.5 Kg/week. The different is big because there
>aren't a stadistic control, so in some cause the woman cook for more
>than 6 person and she has to make torillas. The women that make
>tortillas make more than 1200 tortillas per day, and they have to
>cook all the day. In another case the people don't have the enough
>education for using the woodstove, and they don't use the woodstove
>in the right way. This is a very important point, because if we want
>the people use the improved woodstove, we have to training them, and
>to explain them Why they have to use the new woodstove.
>
>(RWL): Juan - the numbers above are inconsistent. Your "daily" number
>"65.64" is about midway between the "weekly numbers" "93" and "39.5". Is
>it possible that all numbers should be kg/week?
>
> If so, might we say that the daily rate is about 10 kg (+/- about
>3.5 kg)?
>
> And a typical (maybe also maximum) hourly rate might be about 1 kg
>? (This is about 5 kW.)
>
>
>!!RCM> We should further consulte with Juan Carlos Flores. he is the director
>!!of this project in Honduras, and so he can be more accure with this info.
>!!Observe that the plancha stove pictures are from the Honduran project that
>!!has been running for 2 years now..
>!!
>!!
>!!Juan Carlos> Can you participate in this discussion and please gather and
>!!help us with the missing info about the operation of the plancha stove ?
>!!
>!!
>!!Thanks
>!!
>!!
>!!Rogerio
>!!--------------------------------------------------------------------------
>!!Rogerio Carneiro de Miranda Telefax: (505) 276 0555
>!!PROLENA(Nicaragua)
>!!Apartado Postal C-321 Managua Nicaragua
>!!E-mail: rmiranda@sdnnic.org.ni
>!!-------------------------------------------------------------------------
>!!
>----------------------------------------------------------------------
>Juan Carlos Flores Lopez
>Director Ejecutivo PROLENA/Honduras
>Tel/Fax: (504) 32-0639
>P.O.Box 3870 Tegucigalpa, Honduras.
>E-Mail: jflores@prolena.sdnhon.org.hn
>----------------------------------------------------------------------
>
>And my thanks also to Juan. I hope my insertion was OK. Ron
>
>Dear Roger, 7/1/97

Please contact me directly. I would like to discuss with you the Campmaster
Duo principles of heat up as well as down. We make Tortillas all the time on
the HTA Cells. You need high heat on the plate with very little fuel being
consumed. How does 25 cents for 4 hours sound? Lets talk!

Sincerely,

Paul Hait
phait@transport.com

From mike at esd.co.uk Tue Jul 1 12:45:05 1997
From: mike at esd.co.uk (Mike Bess)
Date: Tue Aug 31 21:35:24 2004
Subject: Kenya Ceramic Jiko
In-Reply-To: <v01510100afde7ebefea4@[199.2.222.133]>
Message-ID: <B8QRNDArIQuzUAXZ@esd.co.uk>

Dear Elsen,

Thanks for your comments on the Kenya Ceramic Jiko. My main point was
to say that there has not been, to my knowledge, any systemmatic study
of the KCJ since the mid-1980s. While I believe the KCJ saves charcoal
relative to the traditional jiko, and while I believe the small one
lasts 6-9 months, the larger one 9-12, it would help a great deal, with
little expense if someone were able to make this point statistically,
and be able to say with some scientific confidence that the million or
so KCJs are saving x amount of charcoal, hence y amount of forested
land, and z amount of household income per year. I know for a fact that
the World Bank and many other donors do not take the KCJ seriously as an
"improved" energy efficient device because no-one has made this
scientific or statistical case.

I think the KCJ is a phenomenal market success, and that stove
programmes all over the world should look to it to see why it is a
success. But, it would make the case for using it as a model so much
better if we could also make a sound case for its savings. That was the
point I was trying to make. Cheers, Mike
--
Mike Bess

From jflores at prolena.sdnhon.org.hn Tue Jul 1 13:41:15 1997
From: jflores at prolena.sdnhon.org.hn (jflores@prolena.sdnhon.org.hn)
Date: Tue Aug 31 21:35:24 2004
Subject: Stove price
Message-ID: <199707011543.LAA00635@sdnhon.org.hn>

!!Fecha envio: Mon, 30 Jun 1997 21:45:11 +0100
!!A: stoves@crest.org
!!De: Mike Bess <mike@esd.co.uk>
!!Asunto: Re: Stove price
!!Enviar resp a: stoves@crest.org

!!Dear Juan Carlos,
!!
!!I would like to respond to your questions, and any further questions you
!!might have, at more length. I have just sent a message to Ron about our
!!work in Ethiopia, which I hope you will see. The 300,000 stoves in
!!Addis Ababa have been the improved charcoal stove, the Lakech, not the
!!improved wood stove, the Mirte.

JCF> Thank you for your request. I don't know much about
Ethiopia, but I see that you are working very hard with the stove. I
think that in Ethiopia people prefer charcoal more the firewood for
cooking. In my country, Honduras, people prefer firewood, so this is
the principal reason we have to build the woodstove.

!!Approximately 10,000 Mirte wood stoves have sold in Addis Ababa over the
!!past year, and their numbers are going up. We have set up small micro-
!!credit revolving funds in four cities, including Addis Ababa. I have a
!!full report we prepared for the British Department for International
!!Development, which I can send you, if you like.

JCF> I like you to send me the report. We are working with
micro-credit, and we know that this is a good way to help the people.

!!It has a history of the project, the way the credit schemes are set
!!up and the way they work.
!!This might be interesting to you. We can also put you in contact with
!!our senior Ethiopian counterpart who has been involved with this from
!!the beginning, and who has overseen the credit aspect from the
!!beginning. He will be coming on email within the next few days, so I
!!can send you and all the stovers his address.

JCF> Thank you very much. Could you give to me his e.mail?.
And if we could help you, please contact us.

!!
!!Let me know if we can be of any help, and if you would like, we can send
!!you our DFID report with the credit and finance annexes. Cheers, Mike
!!--
!!Mike Bess

Saludos

Juan Carlos Flores

----------------------------------------------------------------------
Juan Carlos Flores Lopez
Director Ejecutivo PROLENA/Honduras
Tel/Fax: (504) 32-0639
P.O.Box 3870 Tegucigalpa, Honduras.
E-Mail: jflores@prolena.sdnhon.org.hn
----------------------------------------------------------------------

From jflores at prolena.sdnhon.org.hn Tue Jul 1 13:41:26 1997
From: jflores at prolena.sdnhon.org.hn (jflores@prolena.sdnhon.org.hn)
Date: Tue Aug 31 21:35:24 2004
Subject: Plancha Stove (J. Flores)
Message-ID: <199707011543.LAA00634@sdnhon.org.hn>

!!Fecha envio: Mon, 30 Jun 1997 22:51:49 -0600
!!A: stoves@crest.org
!!De: jflores@prolena.sdnhon.org.hn (by way of larcon@sni.net (Ronal W. Larson))
!!Asunto: Re: Plancha Stove (J. Flores)
!!Enviar resp a: stoves@crest.org

!!Stovers: This again was directed (today) to "stoves-owner" rather than
!!to "stoves". This time I have inserted a few questions as well as I have
!!redirected Juan's answers. Ron Larson
!!
!!
!!!!Fecha envio: Fri, 27 Jun 1997 22:12:31 GMT
!!!!A: stoves@crest.org
!!!!De: Rogerio Carneiro de Miranda <rmiranda@sdnnic.org.ni>
!!!!Asunto: Re: Plancha Stove on the web site.
!!!!Enviar resp a: stoves@crest.org
!!
!!!!RWL> wrote:
!!!!>
!!!!> Rogerio: You clearly have a much improved stove over the stove you
!!!!>are replacing.
!!!!>
!!!!> I think it is possible to modify a two-can stove to slide the lower
!!!!>(fuel - pyrolyzing) can in at the lowest level. The upper combustion "can"
!!!!>would then be the built in the adobe firebox structure where you are now
!!!!>combusting the wood.
!!!!> I think the main difficulty will be finding a way to cleanly
!!!!>"snuff" the pyrolysis when the pyrolysis is complete.
!!!!> My hope would be that your users would find it more convenient
!!!!>because they could better control the power level. What can you say about
!!!!>the present ability to get and keep a specific power level?
!!!!> I think the cost could go down a bit, because you would not have
!!!!>the cost of a door.
!!!!>
!!!!RCM> Ron, what 2-can stove are you mentioning ? Could you refresh my
!!!!memory about it? Is that like your charcoal making stove ?
!!!!
!!!!
!!!!RWL> Approximately what length of cooking time should one strive for in
!!!!>Nicaragua ? 40 to 60 minutes
!!!! How many kg wood per hour are presently consumed? ?????????????
!!!!Is there a big difference between the desirable maximum (to achieve a rapid
!!!!boil) and
!!!!>minimum rates of consumption? ???????????????
!!!!Is this achieved by control of the door opening? also, but mostly the women
!!!!traditinaly uses more or less wood to achieve higher energy outputs.
!!
!!JCF> The consumption with the plancha stove is about 20%
!!less than in the non-improved woodstove, and the consumption per day
!!is 65.64 Kg. The people use the woodstove about 10-12 hors per day,
!!the time use depend in the work of the people. For exempt if the
!!person make "tortillas" (a kind of food that is made of corn) they
!!use the woodtove about 12 hours per day. The rates of consumption are
!!from 93 Kg/week to 39.5 Kg/week. The different is big because there
!!aren't a stadistic control, so in some cause the woman cook for more
!!than 6 person and she has to make tortillas. The women that make
!!tortillas make more than 1200 tortillas per day, and they have to
!!cook all the day. In another case the people don't have the enough
!!education for using the woodstove, and they don't use the woodstove
!!in the right way. This is a very important point, because if we want
!!the people use the improved woodstove, we have to training them, and
!!to explain them Why they have to use the new woodstove.
!!
!!(RWL): Juan - the numbers above are inconsistent. Your "daily" number
!!"65.64" is about midway between the "weekly numbers" "93" and "39.5". Is
!!it possible that all numbers should be kg/week?

JCF> Yes, this is an error, the 65.64 Kg is the consumption of
firewood in a week, isn't per day. The 93 and the 39.5 are the
maximum and the minimum consumption.

!!
!! If so, might we say that the daily rate is about 10 kg (+/- about
!!3.5 kg)?

JCF> The daily consumption is 9.37 Kg, with a maximum of 13.28
and the minimum of 5.64 Kg.

!! And a typical (maybe also maximum) hourly rate might be about 1 kg
!!? (This is about 5 kW.)

JCF> Yes, hourly rate might be about 1 Kg, but I'm not sure
about the 5 Kw.

!!
!!!!RCM> We should further consulte with Juan Carlos Flores. he is the director
!!!!of this project in Honduras, and so he can be more accure with this info.
!!!!Observe that the plancha stove pictures are from the Honduran project that
!!!!has been running for 2 years now..
!!!!
!!!!
!!!!Juan Carlos> Can you participate in this discussion and please gather and
!!!!help us with the missing info about the operation of the plancha stove ?
!!!!
!!!!
!!!!Thanks
!!!!
!!!!
!!!!Rogerio
!!!!--------------------------------------------------------------------------
!!!!Rogerio Carneiro de Miranda Telefax: (505) 276 0555
!!!!PROLENA(Nicaragua)
!!!!Apartado Postal C-321 Managua Nicaragua
!!!!E-mail: rmiranda@sdnnic.org.ni
!!!!-------------------------------------------------------------------------
!!!!
!!----------------------------------------------------------------------
!!Juan Carlos Flores Lopez
!!Director Ejecutivo PROLENA/Honduras
!!Tel/Fax: (504) 32-0639
!!P.O.Box 3870 Tegucigalpa, Honduras.
!!E-Mail: jflores@prolena.sdnhon.org.hn
!!----------------------------------------------------------------------
!!
!!And my thanks also to Juan. I hope my insertion was OK. Ron
!!
!!

From jflores at prolena.sdnhon.org.hn Tue Jul 1 13:41:30 1997
From: jflores at prolena.sdnhon.org.hn (jflores@prolena.sdnhon.org.hn)
Date: Tue Aug 31 21:35:25 2004
Subject: Mike Bess on Charcoal and Stove Characteristics
Message-ID: <199707011543.LAA00636@sdnhon.org.hn>

!!Fecha envio: Mon, 30 Jun 1997 21:39:12 +0100
!!A: stoves@crest.org
!!De: Mike Bess <mike@esd.co.uk>
!!Asunto: Re: Mike Bess on Charcoal and Stove Characteristics
!!Enviar resp a: stoves@crest.org

!!First, don't start something like this unless you are willing to follow
!!it through, and that means testing, qualilty control, monitoring, etc.
!!also, don't just train people up and expect them to know all the details
!!of thermo-dynamics, air flow, etc. that make stoves efficient. So,
!!don't abandon them after two years (move on to another project and
!!another country) and expect them to keep the right design, the right
!!number of holes, the right thickness of the metal, etc....

JCF> I'm agree with you. In Honduras were and are a lot of
projects that build woodstove, but they don't follow the woodstove.
They only build the woodstove and they think people learn to use the
stove without training. We know that this is not true, because we
have to training the women (because they are the user) in use and
management.

!!
!!The largest, most expensive Lakech now sells for Birr 20 (about US$1.50)
!!today, compared to the least expensive traditional charcoal metal stove
!!which sells for around EB 14 (about US$ 1). However, 80% of all Lakech
!!sell for less than EB 14 (there's been a terrific price war over the
!!past year), which makes the Lakech cheaper. By the way, when we
!!introduced the stove for market trials in January 1992, the Lakech sold
!!for EB 45 (recommended by the biggest producer) to EB 70 (that's when it
!!was EB 2 to the US$, not EB 6.5 like it is today). Competition, the
!!learning curve, mass production (by skilled artisans) and the stove
!!price falls, quality is pretty standard, and 400 are sold every day.
!!
!!The "traditional" Ethiopian metal stove (there are two main models) is
!!one of the more efficient metal stoves made. They average 28-30%
!!compared with the traditional Kenyan jiko's performance of 20% or lower.
!!High quality craftsmanship has much to do with this. The Lakech liner
!!will last one year, perhaps a bit longer, but the stove pays for itself
!!within two months of regular use. The liner is replaced as a matter of
!!course, and the ceramic shards make great fill for the Addis potholes!

JCF> What is a regular use? How many hour do they use the
stove? What do they cook in the stove? I ask this question because in
my country women use the woodstove for making "Tortillas", and they
use the stove for more than 10 hours daily. Making tortillas is the
principal reason for what the other stove isn't accept for the
people. Here we can find Kerosene stove, but women can't make
"tortillas" on it.

!!
!!
!!Your comments about affordability and market penetration are really
!!pretty on the mark for the Mirte ("better") injera cooker, rather than
!!the Lakech, for reasons I hope I've explained above.
!!
!!The Mirte injera stove was a tougher nut to crack, as you are well aware
!!having worked in Mekele. And we did hear something about your work in
!!Tigray. But, unfortunately we never saw the results (and would like to
!!know more). Efforts to improve injera baking have been underway at
!!least since the early-80s as groups like the Mennonites (Burayu
!!Appropriate Tech Centre) and others tried to improve efficiencies. You
!!are right. Half of all energy (not just cooking energy, but all energy)
!!consumed in households in Ethiopia goes towards baking injera. You've
!!described the baking process right, so I won't repeat.
!!
!!Enclosing the fire is mandatory, and we and others saw that from the
!!earliest days. But, how to do so without getting into the Lorena and
!!Bak dilemmas of self-made stoves, quality and performance all over the
!!universe....? This was the central problem, and still is, for any high
!!mase wood stove.

JCF> We are working on that, because our stove is made of
clay, brick, glass and metal like the Lorena. In order to overcome
this problem, we trained some women in the community. They have to
build the woodstove, and we pay them. In order to keep the quality
in the stove, we give to the person who buy a stove a warranty. We
guarantee the stove, if the woodstove doesn't work in the right
way, we build it again. We have a control in who make the stove. If
the person who make the stove doesn't do it well, we don't pay it.
For this reason we have to be carefull when we select the people
for making stove. First we trained them, and we select only people
that have time and be responsable.

!!We were fortunate because we had worked with John Parry of
Intermediate
!!Technology Workshops (now Parry Workshops) in Kenya and East Africa on
!!housing and roofing materials. One of our Ethiopian counterparts
!!suggested that perhaps a pre-fab multi-section stove made from moulds,
!!using light weight materials might be the answer to developing a low-
!!cost energy efficient, marketable stove. Well, two years later (by
!!1994) and it was. Again, we can discuss technical details, but the
!!stove uses one mould for the four pieces of the main stove, and one
!!mould for the chimney rest. It is made by hand (or can be made
!!mechanically, as it originally was) and can be assembled and
!!disassembled to be moved, transported,etc.

JCF> I like to have more information about this stove.

!!
!!And, it saves energy while it also appeals to cooks because it removes
!!the smoke (number one factor), it is clean and modern (number 2 factor),
!!it is safe from back flashes from flame (number 3 factor) and it saves
!!energy (number 4 factor). These rankings come from over 500 follow up
!!interviews from randomly selected households selected from the 17,000
!!people we have sales records on.
!!
!!The Mirte (as with the Lakech before), was tested in actual houehold
!!tests in Addis (four sets of tests over a two year period), in Bahr Dar,
!!in Awasa. It was cook tested in Gondar, Mekele, Sheshemane,
!!Nazareth....and each time, cooks liked it because of the reasons cited.
!!I often wonder what the ranking would have been had our enumerators not
!!shown up with hats (figuratively speaking) saying "We're interested in
!!energy efficiency". Frankly, I believe the ranking would have stayed
!!the same and the cooks would not have put saving energy as numero uno!

JCF> Yes, you are right. In a study made in Honduras show that
the saving energy isn't the first point for what people buy a new
stove. The order of the reason is the follow: 1) Helth beneficit,
2) the apperence of the stove, 3) the efficiency and the last 4) is
the enviromental proptection.

!!Two years of this effort from April 1995 to March 1997 were supported by
!!the British ODA (now Department for International Development).
!!Frankly, a more professional donor would be hard to find. They were
!!interested, but let us go on with the technical and commercial work. We
!!have four small/micro revolving funds, and 35 active producers,
!!employing over 100 people all over the country. In fact, Mirte
!!production started in Mekele in January and nearly 1,000 stoves have
!!been sold totally commercially, no subsidies, not intermediaries since
!!then. We have some of the best women artisans making the stoves in
!!Gondar, Bahr Dar and Mekele. Regional and local authorities have been
!!totally supportive, and have helped to keep admin and tech costs low
!!(they pay us simple per diems, provide ground transport, organise promos
!!and demonstrations, etc.). We're now promoting this all on our own, and
!!are soliciting corporate sponsorship to expand the Mirte into smaller
!!urban areas, and rural areas. It's going that direction anyway. And,
!!we don't want to lose control of quality control, training (in basic
!!businss and bookkeeping as much as stove quality), technical assistance,
!!etc. Promotion is a must for this product, as with any, and we've held
!!over 90 public, market demonstrations in seventeen cities and towns
!!since September 1995.
!!
!!A neat feature of the Mirte, which we only discovered as we went along,
!!is that it can be fabricated with almost any building materials so long
!!as attention is taken to the mix ratio. The Mirte started out with
!!pumice and cement (5:1 ratio). Pumice, however, is not found everywhere
!!in Ethiopia. So, we tried it with red ash/scoria, another common
!!material that is more widely found than pumice. Bingo, same efficienies
!!(40% improvement in the lab over traditional injera baking, nearly 50%
!!in actual household use). Moving to Tigray and Dire Dawa where no
!!scoria or pumice is found, we tried the predominant building materials-
!!sand and cement. Again, bingo. The stove performs brilliant. I admit,
!!the concept of "portability" is stretched when a six piece stove weighs
!!70 kg, but, people build houses with the same materials. They move the
!!stove once every three months or so, so, no problem with portability...
!!
!!The other surprising aspect of the Mirte is that, unless one fools
!!around with the dimensions of the fire door or starts putting chimneys
!!on the stove, efficiencies stay pretty high and pretty much the same,
!!even with a few cracks in the side. It's robust, And, it pays for
!!itself after less than 3 months for regular household use (twice a week,
!!30 injeras a session, three hours per session), and in less than a week
!!if used commercially (ie, for commercial baking - 300 injeras a session,
!!every day of the week 365 days per year). The stove sells for about EB
!!35 all over the country, with minor variations (we're not into price
!!controls). We keep training producers, so competition increases. Some
!!producers just move sales out to other towns and villages to keep their
!!profit margins which suits our dissemination strategy very well.
!!
!!Yet, there are lots of things to do, and improvements to be made. But,
!!we can talk about that at more length. We believe the proof is in the
!!pudding. Without active intervention, meaning no overt subsidies or
!!interference in the market place, the stove is selling like hotcakes.
!!We realise the "early adopters" are wealthier households and the
!!commercial bakers (women heads of household who bake for restaurants,
!!hotels, and, increasingly, for wealthier households). However, the
!!percolation effect is rapid, and over half of all cumulative sales in
!!Addis are to low income households (verified by those 500+ random
!!surveys). We need to stimulate the market more through promotion and
!!advertising, more people need to be trained, more micro credit needs to
!!be available....but we estimate sales will top 30,000 by the end of this
!!year. If we get more support for these other things, the sky's the
!!limit.
!!
!!I would like to be able to give you government contacts in Addis, but,
!!frankly, the Mirte and the Lakech are really low tech and not much
!!interest to the top government civil servants. They have not paid a bit
!!of attention to this over the past two years, and are much more
!!interested in wind turbines, pvs, and biogas.
!!
!!Fortunately, our Ethiopian counterparts, headed up by Melessew Shanko,
!!(whose email is not working at this moment), but who can be reached by
!!telephone on 251 1 613395, or 187398 (fax info later). For the time
!!being, we are, I'm afraid, the best contacts for this information, but
!!please feel free to get directly in contact with Melessew. By the way,
!!our Ethiopian counterparts did up a superb video in Amharic, which sets
!!out the design, development, use, training, etc. on the stove, and it is
!!sub-titled in English. It's not the highest picture quality, but it
!!really puts it all into context, and I can send you a copy once I get
!!the chance. I think you'll find it very interesting.
!!
!!Finally, before passing on the message I sent to Demetrio on charcoal,
!!we are continuing to work in Ethiopia, having worked all over the region
!!before. We also have a small British grant working with some really
!!good practitioners in Kenya, Uganda, Tanzania and Ethiopia to expand
!!commercial production of "institutional" stoves - ie, stoves used for
!!cooking or baking a lot either for hotels, restaurants and other
!!commercial establishments, or for schools, hospitals and the like. We
!!have recently completed an extensive study on biomass in Uganda, its use
!!and areas for improving its use in households, institutions and small
!!industry for the European Commission. We're doing some private
!!exploratory work on stoves in South Africa, so, we're pretty active on
!!the continent. More on that if you would like.
!!
!!
!!Concerning charcoal prices, here's my message to Demetrio (I don't know
!!yet whether what I send to one of the stovers gets passed on to everyone
!!else, so please excuse me). Also, I've sent Alex half a dozen photos,
!!with info on each for the Web. I see today he has put up two of them.
!!Great stuff. Like I began, I feel like a kid whose just found a lot of
!!new friends. More later, and thanks for the interesting and provocative
!!questions! Ciao! Mike
!!
!!
!!

From BeedieD at Cardiff.ac.uk Tue Jul 1 15:41:53 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:25 2004
Subject: Beedie gasifier & STOVE THREADS
Message-ID: <2BF8D69639B@nrd1s.cf.ac.uk>

Dear Tom and Stovers,

> Dear David and Stovers:
>
> I see a drawing together of the stove people and the gasifier people here.
> David's recent comments indicate that he uses the language and measurements
> of the gasifier group, but is interested in stoves. GREAT!
>
> In the past the stove group has worried a lot about social issues while the
> gasifier group tends to think in terms of megawatt generators. I presume
> the principles of gasification can be applied to stoves however and that
> the gasifier people don't mind social issues.

Biomass enthusiasts like me follow gasification, bioenergy and stoves
because in common with other renewable energy approaches they offer
positive alternatives to the - I believe - environmentally suicidal
continued growth in use of fossil carbon and nuclear fuels. The
significance of the subjects discussed is reinforced by the world
health issue of indoor air pollution, which was only dimly recognised
by myself until regular exposure to the stoves list. Intensive
biomass cultivation/harvesting is also tied up with such things as
biodiversity. There's so much at stake it's slightly surprsing to
me that there aren't more people on these lists.

The downside to being on multiple lists is that if you go away for a
week, your email backlog has increased by at least 100 extra messages.

> More recently the stove group has "taken fire" and seems to be actually
> building and testing stoves. GREAT.

Alas I'm in no position to do so, but I'm impressed by the dedication
of those who are!

> David, can you give us a quick summary of your gasifier and the principles
> that you think apply here in stoves?

A GASIFIER-COMBUSTOR - i.e. a two-stage combustion system in which a
gasifier is close-coupled to a 'secondary combustion chamber'.
The requirement was for an economical, transportable system for
utilising biomass wastes to generate clean hot air for crop drying or
small industrial processes in a rural environment with minimal
pollution. This requirement was met by the design and construction
of a batch-loaded biomass gasification-combustion system rated at
about 200 kW thermal with integral gas-air heat exchanger. The use
of a heat exchanger to transfer the energy of the combustion products
to a clean air stream was seen as a great advantage despite the
inevitable reduction in heat output, as there can be no problem with
contamination.

The unit was manually batch-loaded for minimisation of capital cost,
while the design implemented separate gasification and combustion
zones both to minimise gasifier gas velocities and hence particulate
lift-off, and to enable the use of a novel three-stage secondary
combustion system. This combustion system was intended to generate
low excess air combustion without secondary air control despite the
range of gas production rates occurring during the fuel cycle, by
allowing the flame front to advance or retreat between separated
recirculation zones.

At 200 kW thermal the unit is much bigger than the average stove but
not large in the 'gasification' context of wood-fired electrical
power generation.

Tom, you asked me the PRINCIPLES that I think apply here in stoves.
Well, given that a (wood-)stove might also be termed a batch-loaded
close-coupled biomass gasifier-combustor, I would have to say that
many of the same principles apply, at least in terms of understanding
the processes occurring within. The fuel undergoes similar processes
during its conversion into (hopefully) CO2 and H2O. The principles
of combustion start with time, temperature and turbulence. Add to
them sufficient mixing and appropriate mixture ratio. No doubt most
of the incomplete combustion-related problems of stoves come down to
one or more of these factors. Suppose we could add the typically
problematic conditions of start-up, fuel exhaustion, possibly run-
away. Throw in design factors such as control of air flows,
proportion of heat lost, and operating factors such as fuel
moisture/quality, fuel delivery and settling. The list of variables
is getting out of hand. It would take a book! Or a thesis. So I'll
just promote that a bit instead. The 'best bits', I believe, were:
### the development of techniques for quantifying and understanding
the large cyclic variations in gasification rate and (not) gas
quality, inherent with batch-loading, which significantly challenge
any combustion control system;
### the development of an economical software control system acting
on the primary air supply, and - critically for emissions control -
alerting the operator exactly when to reload;
### improvements in gasifier geometry and primary air delivery,
giving rapid warm-up and reliable fuel settling and utilisation.

> ~~~~~
> If one wanted to index the threads going through the stove list the threads
> would include (but not be limited to...)
>
> TECHNICAL:
> Primative wood stoves (three stone etc.)
> Classical improved wood stoves (swosthee etc.)
> Wood-gas stoves
> Charcoal stoves
> Methods of testing
> Methods of making and manufacturing
> SOCIAL:
> Biomass supply
> charcoal
> health
> Cooking
> Acceptance of new stove technology
> Stove costs
> Stove construction fitted to particular countries
>
> Is this a useful list? Will you add your favorite themes please.

Other threads could be
TECHNICAL:
Operating Parameters, such as:
combustion efficiency
CO emissions
heat losses in the heat transfer process
heat losses due to lack of appropriate insulation

SOCIAL ?:
environmental, eg
forest depletion
dioxins and other highly active trace poisons
GHG (methane, CO2, NOx) production

>
> Yours truly, TOM
> REED

Yours square-eyedly, David.
*******************************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From E.Moerman at stud.tue.nl Wed Jul 2 07:21:17 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:25 2004
Subject: Mike Bess on Charcoal and Stove Characteristics
Message-ID: <4881.s335192@popserver.tue.nl>

Mike Bess:
> First, don't start something like this unless you are willing to follow
> it through, and that means testing, qualilty control, monitoring, etc.
> also, don't just train people up and expect them to know all the details
> of thermo-dynamics, air flow, etc. that make stoves efficient. So,
> don't abandon them after two years (move on to another project and
> another country) and expect them to keep the right design, the right
> number of holes, the right thickness of the metal, etc....

Etienne:
We in Eindhoven agree wholeheartedly. Also we agree that you should not use
the top down approach. Problem is funding. No funds means no
personnel, means abandonment. It's sad, but it is the reality.

Congratulations with your Ethiopian stove project, it sounds great.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From elk at arcc.or.ke Wed Jul 2 08:38:32 1997
From: elk at arcc.or.ke (E. L. Karstad)
Date: Tue Aug 31 21:35:25 2004
Subject: 2can Mk2 charcoal producing stove scrapped
Message-ID: <v01510105afe02355db23@[199.2.222.129]>

Stovers;

Has anyone had success using holes instead of slits for secondary air intake?

Due probably to a combination of design faults, this stove, which
incorperates a smaller pyrolysis chamber below a larger combustion chamber
has been problematic.

The major failings have been in maintaining a flame in the combustion
chamber and a lack of turndown ability when lit.

I suspect the following faults:

1) Holes do not perform as well as slits (turbulance? restricted air flow?)
2) The larger combustion chamber dilutes pyrolisis gases too much.
3) The larger combustion chamber, with pot inserted, reduces chimney flue draw.
4) This stove does not preheat secondary air.
5) Bite Size (I'm having problems chewing).

I'm back to 2can Turbo Mk1 now (as pictured in Alex's web page) & am
modifying the pyrolisis chamber, both air inlets and the gas venting
(chimney) in an attempt to improve turndown controllability.

The next step, should I have any success, will involve insulation & efficiency.

Ronal; I'm not ignoring your questions of 30/6, they're just not relevant
now unless you wish to further investigate negative results.

Regards;

elk

_____________________________
Elsen Karstad
P.O Box 24371 Nairobi, Kenya
Tel:254 2 884437
E-mail: elk@arcc.or.ke
______________________________

From phait at transport.com Wed Jul 2 09:34:43 1997
From: phait at transport.com (John Doe)
Date: Tue Aug 31 21:35:25 2004
Subject: Mike Bess on Charcoal and Stove Characteristics
Message-ID: <199707021328.GAA31426@butch.transport.com>

>Mike Bess:
>> First, don't start something like this unless you are willing to follow
>> it through, and that means testing, qualilty control, monitoring, etc.
>> also, don't just train people up and expect them to know all the details
>> of thermo-dynamics, air flow, etc. that make stoves efficient. So,
>> don't abandon them after two years (move on to another project and
>> another country) and expect them to keep the right design, the right
>> number of holes, the right thickness of the metal, etc....
>
>Etienne:
>We in Eindhoven agree wholeheartedly. Also we agree that you should not use
>the top down approach. Problem is funding. No funds means no
>personnel, means abandonment. It's sad, but it is the reality.
>
>Congratulations with your Ethiopian stove project, it sounds great.
>
>Etienne
>---------------------------------------------
>Mr. Etienne Moerman E.Moerman@stud.tue.nl
>Joh. Buyslaan 71 tel. +31-40-2571491
>5652 NJ EINDHOVEN The Netherlands
>Dear Etienne

I agree with both yours and Mikes comments. You both are very experienced
and practical guys. Mikes achievements and focus as well as yours should be
taken very seriously by the Stovers,as I am sure it is. It is extremely
tough to change habits, but not impossible. It takes time, money, and a heck
of a lot of perseverance. Both of you gentleman have obviously dedicated
yourselves to the cause. It must be difficult to read statements from Green
Horns like me. I have only been working on this project for 16 years. The
approach that I took of using a reflective SST Pyramid shape and organizing
the fuel into a Harmonic Thermal Array is probably way to sophisticated for
third world countries. However, the HTA Cell may not be. It is comprised of
three mass produced parts. The fuel is organized in a specially designed box
that allows the air to penetrate and burn the fuel over a long time. The
box is twice as hot on top as it is on the bottom. Therefore, I bake below
and boil above.The gases escaping from the burning fuel are restricted long
enough to burn more completely.The fuel burns from front to back over a 3 to
4 hour period. If a shorter burn is desired, to save fuel, then less fuel is
put into the stove or the fuel is snuffed out by placing a solid plate on
top of the stove.All parts of the stove nest for mass distribution. The
stove can be made from steel, ceramic, or SST.

Thank you for telling me about the Kenya organization. Have they been
successful in your opinion? Also, what is the average efficiency of an open
campfire vs a Weber Grill vs a closed wood burning stove vs a top down stove
vs a Jecko vs a V stove vs Mike Besses Stove etc. My 10% came from a
Cavemans open fire roasting a Squirrel on a stick (1 million years ago).
Nowadays using 75 briquettes in a Weber Kettle to cook six hamburgers is
about as bad. We do the same thing in a 12 inch Pyromid with 9
briquettes(2250 BTU's) vs 18,000 to 20,000 BTU's in a Weber.

Congratulations on all the work you did at Eindhoven. I heard about your
project almost 13 years ago from Dr. Mutapa at the FAO in Rome.

Sincerely,

Paul Hait
phait@transport.com

From jones at datachem.com Wed Jul 2 13:24:29 1997
From: jones at datachem.com (Jim Jones)
Date: Tue Aug 31 21:35:25 2004
Subject: ANALYZING DIESEL EXHAUST PARTICULATES
Message-ID: <33BA90C8.1225@datachem.com>

DATACHEM LABORATORIES, INC. NOW OFFERS ANALYSIS FOR CARBON PARTICULATE AND DIESEL EXHAUST USING NIOSH METHOD 5040. THE METHOD IS BASED ON COLLECTION USING QUARTZ FIBER FILTERS AND ANALYSIS BY EVOLVED GAS ANALYSIS (EGA) BY THERMAL OPTICAL ANALYZER.DIESEL EXHAUST HAS BEEN CLASSIFIED A PROBABLE HUMAN CARCINOGEN AND NIOSH HAS RECOMMENDED "... THAT WHOLE DIESEL EXCHAUST BE REGARDED AS A POTENTIAL OCCUPATIONAL CARCINOGEN..." AND THAT EMPLOYERS REDUCE WORKERS'EXPOSURES. ACGIH HAS PROPOSED A TWA OF 0.15MG/M3 FOR DIESEL PARTICULATES
CALL RAND POTTER TODAY AT 1-800-356-9135 FOR MORE DETAILS!E MAIL POTTER@DATACHEM.COM

Please forward this memo to the Industrial Hygiene Dept.

From larcon at sni.net Wed Jul 2 19:34:20 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:25 2004
Subject: Stove material (Paul Hait)
Message-ID: <v01540b03afe09281b128@[204.133.251.10]>

Paul said (in response yesterday to Mike bess):

<snip>
> Additionally,I have a local company here in
>Oregon that has developed a unique light weight fire proof cement like
>material that would be great for your stoves. The material could be made in
>africa or shipped since it is as light as a feather. When combined with
>local materials it sets up into a rock hard material that has extremely high
>fire resistance. It is used for fire door material here in the states.

(RWL): Paul - I think more on the list would like to hear more about this
material - cost, lifetime, density, etc?

Paul):
>I find your Charcoal facts to be very interesting also. Are there any
>Briquette operations in Kenya or Ethiopia? I have found that by arranging
>Briquettes in what I call a Harmonic Thermal Array I can get much higher
>temperatures quicker with much less fuel( 75% less). I also take advantage
>of the the heat radiating down as well as up.
<snip>

(RWL): Being one of the few who have probably seen both Paul's and Mike's
excellent designs (for very different markets), I believe one big part of
Paul's design that is transferrable is making the walls of the Mirte more
conical (rather than cylindrical) and bounce more of the energy to the cook
surface, using a reflective material. Mike - your thoughts on reflective
conical walls?

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Wed Jul 2 19:34:44 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:25 2004
Subject: Ethiopian Stove Characteristics (Mike Bess)
Message-ID: <v01540b01afdf466b7c25@[204.133.251.16]>

Mike said:

>Dear Ron,
>
>Wow, I feel like a kid who's just met a lot of new friends!

(RWL):
That's the way I felt as I asked the Ethiopian questions last week.
Ethiopia is a wonderful place and it was wonderful to realize that you
could add so much on (and maybe were largely responsible for) the good
stove development work that is going on there.

<snip>

>Fifteen years living and working with renewable energy in East Africa,
>first on a USAID-World Bank regional project, then with our company
>which is based in the UK, Energy for Sustainable Development.

(RWL): As time goes on, I hope you will describe some more of that work.
How large a group is ESD now and where else are you now doing stove work?

<snip>

> We had an
>excellent kick off with the help of Willem Floor of the World Bank whose
>ESMAP programme is one of the hottest and best in the world.

(RWL): I don't believe Willem is on the list, but several World bank
staff are. I hope they can jump in here to brief us on ESMAP today.

> It sells for half the traditional stove,
>and I'm surprised you didn't see more Lakech than traditional stoves.
>The photos Alex is putting on the Web shows my story; we are seeing
>10,000 Lakech being sold every month, and the Mercato, every supermarket
>and most small markets are filled with them.

(RWL): Certainly 120,000 per year is not bad. But with 60 million
population and maybe 6 million households using charcoal burning stoves
that last about two years, this amounts to about 4% penetration. I believe
that most are also going to be sold only near the big cities - and that's
not where I was..

> We can go into more detail
>about the pluses and minuses, but we still try to keep the quality
>control, keep providing moulds and templates to producers, TA, etc.
>although we've had no government or donor support on this front since
>1995. Our destructive tests and our water boiling tests on the Lakech

(RWL): I'm not sure how destructive tests fit into an efficiency
measurement. How can you afford to do this without any government or donor
support?

(Mike):
>still show it performing around the 35% mark, which is a 25% improvement
>on the already good traditional Ethiopian metal stove. Also, our market
>and household results show that almost 50% of all Addis households own
>and use a Lakech. The World Bank commissioned an independent survey of
>households as a review of our project (within a much bigger World Bank
>energy project) and found in September of 1994 that one quarter of all
>Addis households had the Lakech (and used it regularly).

(RWL): Last year I was only in a remote area (Kaffa in the Southern
region). I wasn't looking that trip much at stoves, and definitely not in
Addis. My guess is that Addis has a larger use of electricity than Lakech
for cooking. True?

Re, your 35% value for efficiency - was this obtained by a water
evaporation technique?

(Mike):
>The Mirte injera stove was a tougher nut to crack, as you are well aware
>having worked in Mekele. And we did hear something about your work in
>Tigray. But, unfortunately we never saw the results (and would like to
>know more).

(RWL): I will try - I don't have anything ready. I am sending
something separately on the smaller charcoal-making units and the injera
cooker was similar - only bigger (20 liter fuel container).

(Mike): Efforts to improve injera baking have been underway at
>least since the early-80s as groups like the Mennonites (Burayu
>Appropriate Tech Centre) and others tried to improve efficiencies.

(RWL): I have not heard previously of this group - can you add more?

<snip>
(Mike):
>Enclosing the fire is mandatory, and we and others saw that from the
>earliest days. But, how to do so without getting into the Lorena and
>Bak dilemmas of self-made stoves, quality and performance all over the
>universe....? This was the central problem, and still is, for any high
>mase wood stove.

(RWL): Could you further explain the term: "dilemmas"? Not so long ago
we have been talking about a wood-burning high-mass "Plancha" stove in
Honduras and Nicaragua. Would you suggest anything about these?

<snip>

(Mike):
>I often wonder what the ranking would have been had our enumerators not
>shown up with hats (figuratively speaking) saying "We're interested in
>energy efficiency". Frankly, I believe the ranking would have stayed
>the same and the cooks would not have put saving energy as numero uno!

(RWL): Just a check. The did or did " not show up" talking about
efficiency? The way this reads, I might surmise that the respondents
intentionally ranked efficiency low because of who was asking or how.

(Mike):
>Two years of this effort from April 1995 to March 1997 were supported by
>the British ODA (now Department for International Development).

(RWL): Anyone there we should invite on to this list?

<snip>
(Mike):
> We're now promoting this all on our own, and
>are soliciting corporate sponsorship to expand the Mirte into smaller
>urban areas, and rural areas.

(RWL): Does "we" refer to ESD alone or is there still a connection with
the Ethiopian government lab group?

<snip>
(Mike): Promotion is a must for this product, as with any, and we've held
>over 90 public, market demonstrations in seventeen cities and towns
>since September 1995.

(RWL): Can you make any estimates of the marketing cost per unit and how
long this will be required?
>
<snip>

(Mike): They move the
>stove once every three months or so, so, no problem with portability...
>
(RWL): I'm surprised to hear about such moves. What are the reasons for this?

<snip>
>
>Yet, there are lots of things to do, and improvements to be made. But,
>we can talk about that at more length.

(RWL): What are your thoughts on improvements? Two concerns I had as I
looked at all units (not just your improved (Mirte) - which I think is very
clever) is that the cover being removed for so long allowed for a lot of
heat release (a lot like running a pizza oven with no top). The other was
that using a low fired (brittle) ceramic for the cook surface seemed so
short-lived to a metal surface (like the Plancha). The cooks carefully
seasoned the surface in a non-stick way that might not be possible with
metal - but I wonder if metal is a way to help also. (Ethiopian friends in
the US all use large Teflon coated electric skillets and (much) larger (3-4
kW?) electric injera cookers are available in Addis)

<snip>

(Mike):
>Fortunately, our Ethiopian counterparts, headed up by Melessew Shanko,
>(whose email is not working at this moment) ....

(RWL): He was not the person I met in Mekkele, I think. I hope you will
try to get him on this list as soon as possible (and congratulate him for
excellent work).
>
(Mike):

>Finally,....
>good practitioners in Kenya, Uganda, Tanzania and Ethiopia to expand
...
>have recently completed an extensive study on biomass in Uganda, its use
.... We're doing some private
>exploratory work on stoves in South Africa, so, we're pretty active on
>the continent. More on that if you would like.

(RWL): I'm sure many would like more (or all) of the above. Thanks for a
very complete and fascinating response on Ethiopia. This is one of the
best stove success stories I have heard. I am delighted to hear of 1 week
(and up) payback times.

I have tried a bit with concrete myself because of seeing your
units and wonder if it might also be possible with the Lakech? When and
where with stoves are the limits for concrete?

In your response to Demetrio (not sent to all, I think)) (snip>

(Mike):
>Thirdly, because it often is such an informal sector activity, transport
>is often either informal (lorries or trucks coming back to big cities
>pick up a few bags of charcoal) or illegal. Illegality has a funny way
>of reducing prices, but we can discuss this in more detail if you like.
>
(RWL): I think many on the list would like to hear about this (although
they mostly seem legal).

(Mike):
>Whatever the case, our work in Kenya and Uganda shows that charcoal can
>be produced sustainably on a competitive basis with charcoal produced on
>a non-sustainable basis because of modern organisation, higher yields,
>closer proximity to markets,etc.

(RWL): Do you have any estimates of present and future Ethiopian charcoal
production efficiency and are you or Melessew Shanko now looking into the
production side of this future (maybe with "waste" gas utilization)?

<snip>

(RWL): Mike - maybe before you joined the list, we have had many
discussions on this list about the relationship between charcoal use and
CO. Have you ever had a chance to make a measurement on this? Any
comments on how large a problem CO is for charcoal users?

We had a member on the list for a while who was in Public Health at
the medical teaching hospital in Jima. He was doing PhD work in Scotland
or Ireland until 6 months ago - doing theoretical work to back up his
detailed field stove emission measurements. His work is much like that of
Kirk Smith; he had to drop off our list as he returned to Ethiopia. (I
want to get his name correct and wil do so ASAP; I think he is very good.)
Do you know of his work?

Many Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From bburt at limestone.kosone.com Wed Jul 2 21:58:00 1997
From: bburt at limestone.kosone.com (Brian Burt)
Date: Tue Aug 31 21:35:25 2004
Subject: Indexing/threads (Reed and Burt)
Message-ID: <199707030157.VAA23873@solstice.crest.org>

> 7. Brian: Was this is somewhat like what you were looking for? Ron
>
> Ronal W. Larson, PhD
> 21547 Mountsfield Dr.
> Golden, CO 80401, USA
> 303/526-9629; FAX same with warning
>
>

What I am wondering is how best to take advantage of this system of
information transfer. There is a certain amount of re-learning that seems
to take place as threads repeat themselves. If the "facts" could be gleaned
from the discussion then they could be catalogued and referenced by both
experienced and new users of the list.

I would envision a indexing system such as you have described in your
message with each of those threads related to concrete statements taken
from messages. In reguard to that perhaps a standardizing of messages might
be encouraged either a introduction or a summary as to why this message is
being posted and the salient points or questions being asked in it. I find
a great many of the messages a bit lengthy even if I find the content
worthwhile and interesting.

I am leaving for an family trip to Newfoundland on Sat. with my wife, 3
kids and a dog. During this quiet retreat I will likely not give much
thought to this problem but I would like to give it some more consideration
when I arrive home in August.

Good luck

Brian

Brian Burt
Burt's Greenhouses
Phone 613-386-3426 Fax 613-386-1211
e-mail bburt@limetone.kosone.com

From english at adan.kingston.net Wed Jul 2 23:39:15 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:25 2004
Subject: Web Page Update
Message-ID: <199707030339.XAA28112@adan.kingston.net>

Dear Stovers

There is now text about, and pictures of, the Lakech and Mirte
Stoves on the Stovers Web Page. (address below)

This is great information to be able to share, and I hope to receive
more like it. There are two basic ways to present pictures combined
with text on a web page. One is to place the text separate from the
pictures and link to them from the text. The other is to set the text
next to the pictures. The first loads faster, the second is more
familiar. Neither way should include any reference to me. So if you
have something to share for this web page, try to write the text with
one of these two styles of presentation kept in mind.

Your Web Muddler
Alex
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Thu Jul 3 07:03:09 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:25 2004
Subject: Turbulent & diffusion blue flames
In-Reply-To: <9706018677.AA867769530@cc2smtp.nrcan.gc.ca>
Message-ID: <199707031103.HAA01631@adan.kingston.net>

Dear Skip, Tom, Etienne, Dave, Piet, Ron and Stovers all

Skip wrote>
> Be careful - blue does not always mean "clean" when that is
> defined as unburned or partially burned combustible
> material. It only means that there are no particulates.

AE: Is a particulate 'anything' containing an unoxidized carbon atom?

>There still can be high levels of carbon monoxide, depending
> on how the combustion process actually occurs.

AE: Is this an unusual phenomenon or are you referring to something
which might help Ron and Elsen with their experiments ?

I understand that most of the non-catalytic, non-pellet, wood stoves
that currently meet the EPA standards in the U.S. are " gasifiers"
with a secondary small diffuse (blue) flame component. What range of
CO/CO2 do they operate in, and over what degree of "turn down" ?
Can we assume any similarity between these stoves and the still
nameless, or namefull, " top down..gasifier..two can..ect" stove
such as Ron and Elsen are working on ? What differentiates them ?

Alex

>
> Skip Hayden
> Senior Research Scientist
> Advanced Combustion Technologies
> Ottawa, Canada K1A 1M1
> TEL: (613) 996-3186
> FAX: (613) 992-9335
> e-mail: skip.hayden@cc2smtp.nrcan.gc.ca
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From larcon at sni.net Thu Jul 3 11:32:59 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:25 2004
Subject: Indexing/threads (Brian Burt)
Message-ID: <v01540b01afe170297edc@[204.133.251.16]>

Summary - reply to Brian Burt on how to make the stove list conversations
more useful.

Brian said:

>What I am wondering is how best to take advantage of this system of
>information transfer. There is a certain amount of re-learning that seems
>to take place as threads repeat themselves. If the "facts" could be gleaned
>from the discussion then they could be catalogued and referenced by both
>experienced and new users of the list.
>
>I would envision a indexing system such as you have described in your
>message with each of those threads related to concrete statements taken
>from messages. In reguard to that perhaps a standardizing of messages might
>be encouraged either a introduction or a summary as to why this message is
>being posted and the salient points or questions being asked in it. I find
>a great many of the messages a bit lengthy even if I find the content
>worthwhile and interesting.

(RWL): I'm afraid I don't know enough about the retrieval technologies
that are now or will be available in the future. All crest files seem to
be indexed alphabetically when you go to look at the crest web site - if
you look for the current "month" - which seems to be year-to-date. The
June file is offered chronologically. (The "stove" listing for the year is
about the same length as that for "bioenergy", but we were several times
larger during June)

I have been amazed at how cheaply one can put data on CD ROMs.
Then you can search (presumably the entire text- not just the headings) for
all messages that combine topics of specific interest. Maybe this is
already possible with the crest files (anyone know?)

I have tried above a summary sentence - using your idea and will
try this for all messages for awhile. Unless crest can supply someone to
do a better job of indexing, I'm afraid it is up to us individually -
through the titles (and maybe through your suggestion for a sumary
sentence).

The beauty of this list idea is that everyone can contribute
whenever they wish - or not. And no-one has to read anything. I know that
we have driven a few persons away from the list because (in the last month
or so) we have added so many messages. We had more tha 300 messages in June
and only 8 or so in January (I can't find the exact statistics I copied a
few days ago)..

A few persons have switched to "stoves-digest" - which only comes
in at the rate of 1 message per day (now, less often last January). I hope
anyone preferring that will let me know - but I think it is probably then
harder to send a message to the whole list.

(Brian):
>I am leaving for an family trip to Newfoundland on Sat. with my wife, 3
>kids and a dog. During this quiet retreat I will likely not give much
>thought to this problem but I would like to give it some more consideration
>when I arrive home in August.
>
>Good luck
>
>Brian

Wow ! a whole month! We'll expect a much better Indexing scheme in
August. Have a good vacation.

Regads Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Fri Jul 4 00:03:39 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:25 2004
Subject: Turbulent & diffusion blue flames (Skip and Alex)
Message-ID: <v01540b06afe21f88f1c1@[204.133.251.6]>

Summary: This asks whether flames (and CO/CO2 ratio) from a pyrolyzer are
not different from those from a gasifier.

>Dear Skip, Tom, Etienne, Dave, Piet, Ron and Stovers all
>
>Skip wrote>
>> Be careful - blue does not always mean "clean" when that is
>> defined as unburned or partially burned combustible
>> material. It only means that there are no particulates.
>
>AE: Is a particulate 'anything' containing an unoxidized carbon atom?
>
>>There still can be high levels of carbon monoxide, depending
>> on how the combustion process actually occurs.
>
>AE: Is this an unusual phenomenon or are you referring to something
>which might help Ron and Elsen with their experiments ?

(RWL): It is my hope (and partially tested belief) that the
time-independence of pyrolysis can allow one to find an air supply
situation that leads to low levels of CO/CO2. David Beedie's point was
that in his gasifier, the CO level only went up at the end of gasification
- a phase that pyrolysis does not reach.

(Alex):
>I understand that most of the non-catalytic, non-pellet, wood stoves
>that currently meet the EPA standards in the U.S. are " gasifiers"
>with a secondary small diffuse (blue) flame component. What range of
>CO/CO2 do they operate in, and over what degree of "turn down" ?
>Can we assume any similarity between these stoves and the still
>nameless, or namefull, " top down..gasifier..two can..ect" stove
>such as Ron and Elsen are working on ? What differentiates them ?

(RWL): As said above, I see the two stoves as very different - . The
nameless stove is definitely not a (complete) gasifier. I'm pretty sure
that the "non-catalytic, non-pellet, wood stoves" do not have separate
primary and secondary air supplies.

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From E.Moerman at stud.tue.nl Fri Jul 4 07:45:09 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:25 2004
Subject: Mike Bess on Charcoal and Stove Characteristics
Message-ID: <6329.s335192@popserver.tue.nl>

Paul Hait:
> Thank you for telling me about the Kenya organization. Have they been
> successful in your opinion? Also, what is the average efficiency of an open
> campfire vs a Weber Grill vs a closed wood burning stove vs a top down stove
> vs a Jecko vs a V stove vs Mike Besses Stove etc. My 10% came from a

Etienne:
I find it difficult to judge the Kenyan organization. Perhaps you better ask
them yourself, I think they are on the list, or else Prasad. I never had
much contact with them I only read one of their publications. I do have the
impression that some of their focal points are successful. They seem to
organize regular regional meetings.

With the efficiencies you mentioned above I have problems. I don't know the
Weber grill, the Jecko stove, the V stove or Mike Besses stove. I probably
know stoves that look and work about the same, but I have problems
remembering the names anyway. I never think a name is very interesting.
Also I did not yet manage to make a working top down stove. What I can
compare is the open fire with the shielded fire (a closed stove). I did not
measure efficiencies for these stoves myself, but we published some reports
on them. What I remember is that a boiling test was used and that we used
the European definition of calorific value (water vapour from the fuel is a
loss in energy). Most likely blocks of White Fir were used (app. 20x20x25mm)
with a moisture content 10-12%. In that case the open fire had efficiencies
20-25% and the shielded fire 35-45%. Both only with good husbandry.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From elk at arcc.or.ke Fri Jul 4 10:02:20 1997
From: elk at arcc.or.ke (E. L. Karstad)
Date: Tue Aug 31 21:35:25 2004
Subject: 2can mk1
Message-ID: <v01510101afe2d16648ef@[199.2.222.130]>

Stovers;

Further modifications and about a dozen trials later..........

Controllability has vastly improved. F.O.M. 1:1 pretty consistant, but
%charcoal production is ranging between 20 & 25%. Once I did manage 30%,
but this was with small pieces of wood randomly arranged in the pyrolisis
chamber & primary air flow didn't allow for a consistant burn in the
combustion chamber (read: lots of smoke- don't bother trying this).

Major changes to date are:

1) Insertion of a perforated steel container in the pyrolisis chamber (same
height, narrower) allowing for a 1.3 cm gap between chamber wall and
pyrolisis container. Primary air flow restricted entering the preforated
bottom of this container only. The bottom of the grate is at the level of
the top of the 3 primary air inlets (space=6cm). The purpose of this
container is to keep fuel away from the walls of the pyrolysis chamber & to
allow for more even air flow through the fuel.

2) Primary air intake are V-shaped now, 6 cm long by 4 cm wid at top.
Valves are adjustable squares of thin steel curved to fit the stove and
slide up and down. being held in place by spring steel clips. A short rod
acts as a hndle for each valve. This allows for independant airflow
adjustments (w. consideration to wind or fine tuning via one vent only) and
more precise control via the ?vernier? type control toward the narrow
bottom of the 'V'.

3) The combustion chamber has been hieghtened to 34 cm above the secondary
air inlet, though this is reduced to 20 cm after the pot has been inserted
into the stove top. Pyrolysis chamber height is 37 cm from the bottom of
the cpyrolisis container. A 6cm gap (as mentioned) between bottom of stove
and bottom of prolysis container matches the V-shaped primary air inlet
heights.

4) Secondary air flow has been increased by bending out the lower steel lip
the 4mm wide slot at 15 places to 1 cm. I'd reckon that overall, this has
opened the secondary air ring up to an average of 8 mm width, though air
flow into the combustion chamber will not be so laminar now.

I'd estimate a turndown of 3 now.... low power is about one third of high
power, and it seems that I've sacrificed a couple points on charcoal
production for increased controllability. Almost no smoke at all.

Overall, I'm happy with the progress to date, especially after battling
with that dog 2can turbo mk2!

Insulation next? I'm concerned that Alex's comments on overheated secondary
air may be a problem here. Any advice anyone?

All the Best;

elk

_____________________________
Elsen Karstad
P.O Box 24371 Nairobi, Kenya
Tel:254 2 884437
E-mail: elk@arcc.or.ke
______________________________

From phait at transport.com Fri Jul 4 11:23:27 1997
From: phait at transport.com (John Doe)
Date: Tue Aug 31 21:35:25 2004
Subject: Mike Bess on Charcoal and Stove Characteristics
Message-ID: <199707041515.IAA15125@butch.transport.com>

>Paul Hait:
>> Thank you for telling me about the Kenya organization. Have they been
>> successful in your opinion? Also, what is the average efficiency of an open
>> campfire vs a Weber Grill vs a closed wood burning stove vs a top down stove
>> vs a Jecko vs a V stove vs Mike Besses Stove etc. My 10% came from a
>
>Etienne:
>I find it difficult to judge the Kenyan organization. Perhaps you better ask
>them yourself, I think they are on the list, or else Prasad. I never had
>much contact with them I only read one of their publications. I do have the
>impression that some of their focal points are successful. They seem to
>organize regular regional meetings.
>
>With the efficiencies you mentioned above I have problems. I don't know the
>Weber grill, the Jecko stove, the V stove or Mike Besses stove. I probably
>know stoves that look and work about the same, but I have problems
>remembering the names anyway. I never think a name is very interesting.
>Also I did not yet manage to make a working top down stove. What I can
>compare is the open fire with the shielded fire (a closed stove). I did not
>measure efficiencies for these stoves myself, but we published some reports
>on them. What I remember is that a boiling test was used and that we used
>the European definition of calorific value (water vapour from the fuel is a
>loss in energy). Most likely blocks of White Fir were used (app. 20x20x25mm)
>with a moisture content 10-12%. In that case the open fire had efficiencies
>20-25% and the shielded fire 35-45%. Both only with good husbandry.
>
>Etienne
>---------------------------------------------
>Mr. Etienne Moerman E.Moerman@stud.tue.nl
>Joh. Buyslaan 71 tel. +31-40-2571491
>5652 NJ EINDHOVEN The Netherlands
>Dear Etienne,

Thankyou for the reply! I am excited about the level and character of the
people involved in this stove world. I have never encountered a finer group
of dedicated and focused individuals. You being one of the most practical.
It must of come from years of dedicated effort and disappointment. Since I
am a late-comer to the list I know that I have missed years of solid
communication. If my statements seem a little bit market driven and not
research driven it is because I am responsible for both sides of the
equation at my company. I want people in general to recognize that by
organizing energy in an HTA Array in a cell they can use the energy both up
and down. I use one briquette( Kingsford type)~250 BTU's according to Tom
Reed, to cook for one person. How many BTU's did your stoves use to cook for
one person?
Is your 20% fire using the heat under the fire as well as above? Was the
wood organized TEEPEE style? How much of the fire did the pot cover? How
high was the pot over the fire? Was the fire indoors(no wind) or outdoors?
Was the fire in a hole with a ring of rocks, or was it on a flat surface?Was
it shielded so the heat would be more focused? What was the time interval to
peak heat and how long did it stay that way with out refueling? Was the wood
layed randomly? Was there a lot of pitch in the wood? Considering the
scarcity of wood in the third world it seems to me that your tests should
have been done with dung,Acacia,Mesquite,Gum,Corn Cobs, etc.The wood you
used sounds like it came from a fuel plentiful area. Sorry for all the
questions, but I still think that the average outdoor fire using different
types of woods at different moistures in a black hole with a ring of rocks
is much less efficient than 20%.
In a sealed box your % efficiency sounds right if the heat is only used on
top of the box.
The American Indian learned that his Teepee would fill up with smoke if he
did not ORGANIZE his burning wood in a Pyromid shape. He created
focus,higher velocity,higher heat, and faster cooking. All I did is drop a
SST Pyromid structure over the Indians fire(like what is on the back of the
US One Dollar bill under Gods Eye) and achieved an environmentally
controlled campfire. As the gases rise in the Pyromid they get naturally
compressed. I put a plate on the top where I set a pot. I then surrounded
the pot with Ronals wind guard. At the top of the Pyromid, below the plate,
I punched holes to let the gases out that were ignited. There is an access
door on one side of the Pyromid that is damper regulated. The heat focus is
controlled and is very precise. I placed the Pyromid on a combustion surface
about 3.5 inches off of the ground and then put a drawer under the fire. I
was now using the heat up to boil and cook and the heat down to bake and
warm.I have found that the heat up is about 2x as hot as the heat down.Our
efficiency statements come from using the heat both up and down. Are we
doing something wrong from the stove researchers point of view?
It was interesting to see that you do not remember stove names. What was the
name of your favorite stove? In your opinion what is the best concept in the
world today? To many questions I know,but your knowledge is invaluable to
the Stovers.
Great to hear from you !

Sincerely,

Paul Hait
phait@transport.com

From phait at transport.com Fri Jul 4 11:54:20 1997
From: phait at transport.com (John Doe)
Date: Tue Aug 31 21:35:25 2004
Subject: Pyromid Improved ?&#~!
Message-ID: <199707041546.IAA15241@butch.transport.com>

> Dear Mr. Doe
>
>We just finished firing up the new Pyromid (15) and knew you were
>waiting for design input.
>
>Idea numero uno.--
>---- for smoke free wood fired grilling-----
>Suspend a cone (or pyramid shape will do in a pinch) from the centre
>of your grill, ( you will need to stamp a small hole there) this
>will funnel the smoke to a tiny swirl venturi sitting on top of the
>grill. This will have provision for another pot perched on top.
>
>Yours Radiantly
>
>Alex
>P.S. We used the charcoal from our "cone and pail" tests. With this
>fuel the Pyromid was truly a rapid cooker.
>Alex English
>RR 2 Odessa Ontario
>Canada K0H 2H0
>613-386-1927
>Stoves Web Site http://www1.kingston.net/~english/Stoves.html
>Dear Alex,

Sorry for the slow response. I hope you like the product? Your pictures that
you have put of the web is a great contribution. Good job! Your suggestion
is our Pyromid enclosed Campfire. We need to stay in touch as you use your
Pyromid 15. Hopefully, you can see the effects of fuel organization? What do
you think?

Sincerely,
Paul

From phait at transport.com Fri Jul 4 12:30:59 1997
From: phait at transport.com (John Doe)
Date: Tue Aug 31 21:35:25 2004
Subject: NAME CONTEST
Message-ID: <199707041623.JAA15399@butch.transport.com>

> TOM REED, CSM, reedtb@compuserve.com
>ELK et al:
>
>Sounds like you are making great quantitative progress with what you call
>the "two can stove". Congratulations - push on! Here are a few comments
>for your consideration.
>
>You asked what happens to the charcoal if it is not extinguished when the
>volatiles have all been consumed. If you put a thermocouple in the middle
>of the charge it will show you
>
>a) initially room temperature air passing by on the way up to the "flaming
>pyrolysis" zone (yes, there is a flame buried in the pile - we built a
>"transparent gasifier" with gold reflective insulation and could observe
>it)
>
>b) a very rapid rise in temperature to about 500 C as the flame approaches
>the thermocouple
>
>c) very little drop in temperature as the volatile flame approaches the
>bottom grate
>
>d) an immediate sharp rise in temperature as charcoal begins to burn
>
>So, one TC (or dial gauge thermometer) reveals the history quite
>accurately. I recommend that we all use such a buried TC for our tests
>
> ~~~~
>NAME OF STOVE CONTEST:
>
>NAME OF STOVE:
>
>It has been most amusing to follow the changing names given this stove. I
>initially (in 1985, patent memos to SERI/NREL) called it an
>"UPSIDEDOWNDRAFT GASIFIER" stove by analogy to the conventional "downdraft"
>gasifier, well known during WWII and also to emphasize that it cooked with
>GAS. After a year or two I realized the "upsidedowndraft", while colorful,
>was not informative to non-English speaking people (like Harry LaFontaine).
> So I changed to calling it the "Inverted downdraft gasifier-stove". When
>Fred Hottenroth produced a commercial model he called it a GASFIRE stove
>(1989). I have also called it a WOOD-GAS stove, with strong emphasis on
>GAS to avoid confusion with a few thousand wood stoves built through the
>ages. Gasifier stoves are NEW (and include the "J" stove of
>Verhart-Eindhoven-Antal).
>
>When Ron Larson called me to ask about charcoal making stoves he renamed it
>"a CHARCOAL MAKING" stove (1992). Others call it the TOP LIGHTED stove.
>Now you call it the TWO CAN" stove.
>
>It seems to me we have here the "blind men and the elephant" syndrome.
>Each person sees what he/she thinks is important. Coming from gasifiers
>and having used gas stoves, I think WOOD-GAS STOVE (as opposed to WOOD
>STOVE) is most descriptive and exciting. Ron comes from Ethiopia where the
>possibility of producing charcoal (always a nuisance in my eyes) was the
>most important feature.
>
>Now you use TWO CAN STOVE to describe it. Does the fact that it can (but
>not necessarily is) be made from two tin cans best catch the essense?
>
>I suggest we all submit our best choices for a single name to catch the
>essense. Ron can collect the names and we can all vote. Majority wins and
>we all sink or swim with the result.
>
> ~~~~~
>Fussing over names may seem nit-picking. Nonsense. A good name is almost
>as important as a good product.
>
>OIL SHALE is not truly a shale, nor does it contain oil. It is keragenated
>marlstone. How much funding would Congress have appropriated for research
>on keragenated marlstone. So they lied a little. (And the self-deception
>of the oil companies cost them and us a few hundred billion $.
>
>So let's pick an honest, descriptive name that emphasizes what is new.
>
>Yours truly, TOM
>REED

>Dear Tom,

You make cooking gas and you make charcoal in a two can system. The fuel
burns from top down and the gases rise for cooking. You want the name to
make sense.
Therefore, I would suggest you give the stove a name that creates curiosity
and causes a person to want to understand what he doesn't understand.The
words
TWO,GAS,CHARCOAL,STOVE,PYROLISIS,CAN,TOP,DOWN,TOM,ELK,RONAL,REED,LARSON,STOV
ER,CREST,MAJOR DOMO, Etienne etc all come into play. Here is my suggested name;

1. The REED Stove. REED stands for ( Ronal,Elk,Etienne Development)Stove.
In this name you all get recognized. The ones that have made it work and the
one who says he can't make it work thus creating a balance and and a little
humility.

People will want to know what the REED stove is. Then you will tell them
that it is a Top Down Natural Fuel Burning Charcoal Making Pyrolizing Two
Can Super Efficient Revolutionary Highly Researched World Stove
concept.Whew!In short, The REED stove.Just a thought.

Sincerely,

Paul Hait a competitor

From larcon at sni.net Fri Jul 4 14:38:32 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:25 2004
Subject: 2can Mk2 (Karstad)
Message-ID: <v01540b03afe2cf99a3fe@[204.133.251.6]>

Summary: Ideas offered on Karstad's Mk2 version of a 2-can charcoal maker
- reasons for difficulty and possible solutions.

Elsen said on 2 July:

>Has anyone had success using holes instead of slits for secondary air intake?

(RWL) Yes. They should be equivalent, maybe even better (the inter-hole
space provides structural rigidity). How many secondary air holes did you
place in the new (horizontal hole axis) design? Generally I have had
trouble when they are not close enough and are too large. I generally use
a hammer and large nail, when working with something like stove pipe -
drilling takes too long.

>Due probably to a combination of design faults, this stove, which
>incorperates a smaller pyrolysis chamber below a larger combustion chamber
>has been problematic.
>
>The major failings have been in maintaining a flame in the combustion
>chamber and a lack of turndown ability when lit.

(RWL): Could this be a leakage of air (always too much air) or the reverse?
>
(Elsen):
>I suspect the following faults:
>
>1) Holes do not perform as well as slits (turbulance? restricted air flow?)

(RWL): See above. This should not be the problem - might try more
holes. I have no definitive "scientific" comparisons, but both seemed to
work OK.

>2) The larger combustion chamber dilutes pyrolisis gases too much.

(RWL): Sounds like a possibility. One solution may be to fill the inner
part of the upper chamber (even with a fuel filled can). In general,
chimneys seem to suffer more from being too wide rather than too narrow
(many draw cold air down on the outside).

>3) The larger combustion chamber, with pot inserted, reduces chimney flue draw.

(RWL): Possible. Does the system work well enough without the pot? What
is the pot-chimney spacing? Could you try a slightly smaller pot?

>4) This stove does not preheat secondary air.

(RWL): Is there a way to do so? (I'm thinking of two parallel disks.)

>5) Bite Size (I'm having problems chewing).

(RWL): Hmmm.
>
>I'm back to 2can Turbo Mk1 now (as pictured in Alex's web page) & am
>modifying the pyrolisis chamber, both air inlets and the gas venting
>(chimney) in an attempt to improve turndown controllability.
>
>The next step, should I have any success, will involve insulation & efficiency.
>
>Ronal; I'm not ignoring your questions of 30/6, they're just not relevant
>now unless you wish to further investigate negative results.

(RWL) I would like hear more about the negative results - as there are so
many types of problem possible. We may never understand the problem, but
it will probably help us all if we try.

What was the total height from secondary air holes to cook pot bottom?

Did the flames not hold at the secondary air holes?

How long were the flamelets?

Did this model have the same rotating closure for the primary air holes?

The only time I tried something this big, I had one 20 liter can (30 cm
dia.) on top of another (slit between, not holes) and then a flat surface
with the injera "plate" (60 cm dia) above. The only problem was that the
inner part of the injera plate got much hotter than the outer. When trying
to boil water, this would not be as big a deterrent. My recollection was
that I had a barrier for the inner part of the fuel container (since it is
hard for the secondary air to get in so far). (The fuel in the center was
partly contained in an inverted smaller can.)

There is a hand book (I don't own) on resistances for obstructions
and bends and constrictions/expansions in a pipe (can't remember the name
right now). Maybe the combination you have has changed the resistance too
much over the Mk I version. This handbook tells one how to make that
calculation (except I never found the stove configuration in this book.)
Someone might tell us how much extra resistance occurred with your mods to
a simple two can design.

I think it is very important to have the right pressure
distribution inside the operating stove and possibly the venturi effect
that Alex is working on was totally prevented with the big area expansion
that you have. I remember reading somewhere that minimum resistance
resulted from a constant cross section (which has a peculiar definition in
your design with 5 cm. of narrower pipe above the secondary air holes, then
a constriction (I think) and then a much larger volume region.)

What we need is an ability to predict the pressures inside the
stove. Any modelers lurking who can do this job? (for free!)

If the pressure is not low enough at the secondary air inlet (also
the upper height of the fuel) then not enough primary air will be "forced"
up through the fuel and not enough secondary air "forced" in either. From
your description, this sounds like a possible cause for the problems. I
would strive to obtain the equal cross-sectional criterion as much as
possible - starting with the 6-8 mm gap that Etienne has recommended.
(When the pyrolysis gases and secondary air meet, we have some other
criteria - that still remains to be spelled out.)

Even though you had no success, I hope you will send a photo or two
of Mk II on to Alex as well. Good luck with your new mods to Mk I.

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Fri Jul 4 20:44:24 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:25 2004
Subject: Stove Characteristics (Bess, Moerman, Hait)
Message-ID: <v01540b04afe31dd20ae2@[204.133.251.5]>

Summary - clarification requested on three opinions on top-down
(charcoal-making) stoves.

In a response to the 4th paragraph of Mike Bess' comments of 30 June:

>>Mike Bess:
>>> First, don't start something like this unless you are willing to follow
>>> it through, and that means testing, qualilty control, monitoring, etc.
>>> also, don't just train people up and expect them to know all the details
>>> of thermo-dynamics, air flow, etc. that make stoves efficient. So,
>>> don't abandon them after two years (move on to another project and
>>> another country) and expect them to keep the right design, the right
>>> number of holes, the right thickness of the metal, etc....

Then Etienne said on July 2:
>>We in Eindhoven agree wholeheartedly. Also we agree that you should not use
>>the top down approach.

<snip>

And Paul Hait said on July 2 also:

>I agree with both yours and Mike's comments. <snip>

(RWL): I need clarification.

1. Mike: Did you say don't use top down?

2. Etienne: What are your (Eindhoven) reasons for being opposed to top
down (charcoal-making) stoves?

3. Paul: In something you wrote a while back, I thought I heard a
favoring for top-down (charcoal-making) stoves. Without such more
efficient charcoal production, I think we can expect more widespread
prohibition of charcoal using stoves.

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Fri Jul 4 20:44:36 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:25 2004
Subject: HTA Cell Stove (Paul Hait - "John Doe")
Message-ID: <v01540b05afe322d03712@[204.133.251.5]>

Summary - This is to inquire further on the characteristics of Paul Hait's
HTA Cell Stove.

On June 2, Paul said:

> <snip> The
>approach that I took of using a reflective SST Pyramid shape and organizing
>the fuel into a Harmonic Thermal Array is probably way too sophisticated for
>third world countries. However, the HTA Cell may not be. It is comprised of
>three mass produced parts. The fuel is organized in a specially designed box
>that allows the air to penetrate and burn the fuel over a long time. The
>box is twice as hot on top as it is on the bottom. Therefore, I bake below
>and boil above.The gases escaping from the burning fuel are restricted long
>enough to burn more completely.The fuel burns from front to back over a 3 to
>4 hour period. If a shorter burn is desired, to save fuel, then less fuel is
>put into the stove or the fuel is snuffed out by placing a solid plate on
>top of the stove. All parts of the stove nest for mass distribution. The
>stove can be made from steel, ceramic, or SST.

1. Is this designed for wood, or charcoal or both? (I think wood and
assume that in the following)

2. Have you tried any efficiency (water boiling) tests yet?

3. We had some very interesting discussions on this list (maybe 6 months
ago?) about firing from front to back (as a way to limit the amount of wood
that would be participating in the flame at any one time. Does anyone
remember who brought that subject up and when? (apparently standard - but
new- in some residential heating stoves). Paul - could you describe the
nature of the flame and any smoke you see in the HTA Cell?

4. Can you describe any chimneys or wind shields?

5. Your method of proposed snuffing makes me think that you are using the
same perforated cook surface as in your "Pyromid" charcoal-burner.
Correct? If so, then the chimney (none) and windshield (small, above the
cook surface)) issues must be a lot like the Pyromid.

6. I wonder if any stovers on this list have ever heard of this
combination - it is something like Rogerio's and Juan's "Plancha" - but
with smoke coming through the perforated cook plate. Is this intended only
for outdoor cooking?
(presumably frying eggs is as shown on your web page? But meats are cooked
directly on the perforated top plate?

7. Paul - I think you may have a winner (but I reserve judgement until
hearing about the smoke and efficiency issues).

8. Is there any controllability? (Any air supply control?) Your
"Pyromid" has a somwhat crude air control through "flaps" on the upper wind
screen. Is this similar?

9. When can you start sending them out for tests by the stoves list?

10. What price?

Congratulations and Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Fri Jul 4 20:44:25 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:25 2004
Subject: Cone Venturi (English and Hait)
Message-ID: <v01540b07afe334a7684d@[204.133.251.5]>

Summary: Request for clarification on what Alex is learning from his
cone-venturi tests and on Paul's "Pyromid enclosed Campfire".

On June 26 (repeated in a message from Paul Hait today), Alex said:

>>Idea numero uno.--
>>---- for smoke free wood fired grilling-----
>>Suspend a cone (or pyramid shape will do in a pinch) from the centre
>>of your grill, ( you will need to stamp a small hole there) this
>>will funnel the smoke to a tiny swirl venturi sitting on top of the
>>grill. This will have provision for another pot perched on top.
<snip>

With response from Paul ("John Doe"):

>>Dear Alex,
>
<snip> Your suggestion is our Pyromid enclosed Campfire. <snip>

(RWL): 1. Alex: In your situation, I think you are always producing
charcoal (in top-down firing fashion) and that your cone is free of fuel.
You draw in some more secondary air through the venturi action and complete
combustion above the venturi. Is this correct? (Could you also give us a
short tutorial on venturis)

2. Paul ("John Doe"): I'm guess your cone is full of wood and is
probably bottom lit, with some combustion above the cone and no charcoal
production (and maybe no venturi action). So I guess that very different
design principles are involved. Could you comment on my assumptions?

3. Paul: I still also guess that your "Pyromid enclosed Campfire" may be
very valuable and I have not seen it in any stove literature (anyone?).
Could you describe its operation (controllability, smoke, lighting, etc,)
and benefits (when you would and would not recommend it). What is the
cost?

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Fri Jul 4 20:44:42 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:25 2004
Subject: 2can mk1
Message-ID: <v01540b02afe30c44eafd@[204.133.251.5]>

Summary: Comments on Elsen's return to his (modified) Mk I design.

Elsen said:

<SNIP>

>Major changes to date are:
>
>1) Insertion of a perforated steel container in the pyrolisis chamber (same
>height, narrower) allowing for a 1.3 cm gap between chamber wall and
>pyrolisis container. Primary air flow restricted entering the preforated
>bottom of this container only. The bottom of the grate is at the level of
>the top of the 3 primary air inlets (space=6cm). The purpose of this
>container is to keep fuel away from the walls of the pyrolysis chamber & to
>allow for more even air flow through the fuel.

(RWL): a. Is this a transferrable container (easy in / easy out) to allow
also for snuffing of the charcoal?
b. Any reason for the 1.3 cm gap? (convenient can size?)
c. Do you think the radial temperature variation is now less? (because the
inner cylinder achieves a higher temperature?)
d. I don't see why there should be any difference in the "even-ness" of
the air flow (except maybe due to better radial temperature uniformity).
e. How tight was the sealing at the top of this new inner cylinder? (It
would seem that you need complete separation of the lower pyrolysis chamber
from the upper combustion chamber.) And how was this sealing obtained?
>
>2) Primary air intake are V-shaped now, 6 cm long by 4 cm wid at top.
>Valves are adjustable squares of thin steel curved to fit the stove and
>slide up and down. being held in place by spring steel clips. A short rod
>acts as a hndle for each valve. This allows for independant airflow
>adjustments (w. consideration to wind or fine tuning via one vent only) and
>more precise control via the ?vernier? type control toward the narrow
>bottom of the 'V'.

(RWL): a). Sounds like a very good approach to controlling primary air -
but maybe expensive to produce?.
b). Do you think this was the main reason for now getting a 3:1 turndown
ratio? (you have some very large maximum air holes).
c). When you were running at maximum and minimum power level, about how far
open were these openings?
d) Do you think with this arrangement that you might get away with just
one single opening? Maybe with a horizontal slide?
e) Do you think you could reduce the 6 cm bottom gap (to save height and money)?

>
>3) The combustion chamber has been hieghtened to 34 cm above the secondary
>air inlet, though this is reduced to 20 cm after the pot has been inserted
>into the stove top. Pyrolysis chamber height is 37 cm from the bottom of
>the cpyrolisis container. A 6cm gap (as mentioned) between bottom of stove
>and bottom of prolysis container matches the V-shaped primary air inlet
>heights.

a) What weight of wood can you now use?
b) Are you still using an outer wind screen?
c) What is the spacing between pot and combustion chamber?
d) The pot is 14 cm high?
e) How supported?
>
>4) Secondary air flow has been increased by bending out the lower steel lip
>the 4mm wide slot at 15 places to 1 cm. I'd reckon that overall, this has
>opened the secondary air ring up to an average of 8 mm width, though air
>flow into the combustion chamber will not be so laminar now.

(RWL): a) Where is the flame attachment?
b) I envision that the lower "perforated" container has created a much
wider (1.3 cm?) "lip" at the lower edge of the secondary air gap. What
effect does this have on flame attachment?
>
>I'd estimate a turndown of 3 now.... low power is about one third of high
>power, and it seems that I've sacrificed a couple points on charcoal
>production for increased controllability. Almost no smoke at all.

(RWL): Great! I think this is a very important part of efficiency and
user satisfaction - worth the reduction of charcoal production. But can
you guess what has caused this reduction? Is it charcoal consumption at
the bottom?
>
>Overall, I'm happy with the progress to date, especially after battling
>with that dog 2can turbo mk2!

(RWL): And I just sent thoughts on that! Sounds like it will be hard to
get you to think about it - and I don't blame you. Glad to hear of these
successes.
>
>Insulation next? I'm concerned that Alex's comments on overheated secondary
>air may be a problem here. Any advice anyone?

(RWL): Well worth an experiment. What type of insulation?

How high was the wind screen?

Good progress!! Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Fri Jul 4 20:44:43 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:26 2004
Subject: Pyromid and/or HTA Cell Stove (Paul Hait)
Message-ID: <v01540b06afe32f38217c@[204.133.251.5]>

Summary - request for clarification on the differences and similarities
between two Paul Hait stoves.

On July 4, Paul said in a response to Etienne Moerman (unknown date):

> <snip> . If my statements seem a little bit market driven and not
>research driven it is because I am responsible for both sides of the
>equation at my company.

(RWL): Please keep up your market orientation. I believe the only
question anyone has is how you can control other "market-driven"
competition in third world markets.

(Paul):
>I want people in general to recognize that by
>organizing energy in an HTA Array in a cell they can use the energy both up
>and down. I use one briquette( Kingsford type)~250 BTU's according to Tom
>Reed, to cook for one person. How many BTU's did your stoves use to cook for
>one person?
> Is your 20% fire using the heat under the fire as well as above? Was the
>wood organized TEEPEE style? How much of the fire did the pot cover? How
>high was the pot over the fire? Was the fire indoors(no wind) or outdoors?
>Was the fire in a hole with a ring of rocks, or was it on a flat surface?Was
>it shielded so the heat would be more focused? What was the time interval to
>peak heat and how long did it stay that way with out refueling? Was the wood
>layed randomly? Was there a lot of pitch in the wood? Considering the
>scarcity of wood in the third world it seems to me that your tests should
>have been done with dung,Acacia,Mesquite,Gum,Corn Cobs, etc.The wood you
>used sounds like it came from a fuel plentiful area. Sorry for all the
>questions, but I still think that the average outdoor fire using different
>types of woods at different moistures in a black hole with a ring of rocks
>is much less efficient than 20%.
>In a sealed box your % efficiency sounds right if the heat is only used on
>top of the box.
>The American Indian learned that his Teepee would fill up with smoke if he
>did not ORGANIZE his burning wood in a Pyromid shape. He created
>focus,higher velocity,higher heat, and faster cooking. All I did is drop a
>SST Pyromid structure over the Indians fire(like what is on the back of the
>US One Dollar bill under Gods Eye) and achieved an environmentally
>controlled campfire. As the gases rise in the Pyromid they get naturally
>compressed. I put a plate on the top where I set a pot. I then surrounded
>the pot with Ronals wind guard. At the top of the Pyromid, below the plate,
>I punched holes to let the gases out that were ignited. There is an access
>door on one side of the Pyromid that is damper regulated. The heat focus is
>controlled and is very precise. I placed the Pyromid on a combustion surface
>about 3.5 inches off of the ground and then put a drawer under the fire. I
>was now using the heat up to boil and cook and the heat down to bake and
>warm.I have found that the heat up is about 2x as hot as the heat down.Our
>efficiency statements come from using the heat both up and down. Are we
>doing something wrong from the stove researchers point of view?
>It was interesting to see that you do not remember stove names. What was the
>name of your favorite stove? In your opinion what is the best concept in the
>world today? Too many questions I know,but your knowledge is invaluable to
>the Stovers. <snip>

(RWL): 1. Whew - glad I don't have to answer all those questions.

2. Paul: I need clarification on the differences in the above between the
"Pyromid" and the "HTA Cell Stove" that you described on July 2 (and that I
just sent a message on). I have been thinking that the "HTA Cell Stove"
had no pyramid (tilted) shaping. Also that the Pyromid did no cooking
below?

3. Is the above all for charcoal? Etc. etc.

4. The wind shield you described as mine must go back much further - I
like the analysis of that shield done by Sam Baldwin in his thesis. Anyone
ever seen any experimental validation?

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Fri Jul 4 20:45:24 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:26 2004
Subject: NAME CONTEST (Reed and Hait)
Message-ID: <v01540b08afe339eaa4c2@[204.133.251.5]>

Summary: this is on Tom Reed's and Paul Hait's comments on naming a
"charcoal-making stove".

Tom Reed said a while back (as repeated today by Paul):
<snip>
>>I suggest we all submit our best choices for a single name to catch the
>>essense. Ron can collect the names and we can all vote. Majority wins and
>>we all sink or swim with the result.
<snip>
>>So let's pick an honest, descriptive name that emphasizes what is new.
<snip>

Paul said today:
(snip>
>You make cooking gas and you make charcoal in a two can system. The fuel
>burns from top down and the gases rise for cooking. You want the name to
>make sense.
>Therefore, I would suggest you give the stove a name that creates curiosity
>and causes a person to want to understand what he doesn't understand.The
>words
>TWO,GAS,CHARCOAL,STOVE,PYROLISIS,CAN,TOP,DOWN,TOM,ELK,RONAL,REED,LARSON,STOV
>ER,CREST,MAJOR DOMO, Etienne etc all come into play. Here is my suggested name;
>
>1. The REED Stove. REED stands for ( Ronal,Elk,Etienne Development)Stove.
>In this name you all get recognized. The ones that have made it work and the
>one who says he can't make it work thus creating a balance and and a little
>humility.
>
>People will want to know what the REED stove is. Then you will tell them
>that it is a Top Down Natural Fuel Burning Charcoal Making Pyrolizing Two
>Can Super Efficient Revolutionary Highly Researched World Stove
>concept.Whew!In short, The REED stove.Just a thought.
>
>Sincerely,
>
>Paul Hait a competitor
>
(RWL): 1. Paul - I've duly noted your vote, per Tom's request.

2. I've tried a lot of different names in different countries and found
that eyes light up quickest when saying "charcoal-making stove".
a. The cooking part comes across easily with "stove".
b. Everyone knows "charcoal" (but not "pyrolysis" or
"inverted-down-draft", etc.)
c. "Making" is easily understood - as is the implication that one
can sell or use a high-value product.

3. I would avoid "two-can" as this is only one of many possible forms.
One-piece ceramic seems a likely winner to me whereever clay is now widely
used. "Top-down" is descriptive and unique but doesn't capture the stove
values.

4. This type of stove has been tested by Tom Reed, Tom Duke, Elsen Karstad,
Alex English (with major modifications) and myself (and to my knowledge
no-one else). True? (Tom Duke - we need to hear from you again)

5. Paul: You have the word "competitor" at the end (for the first time?).
Does this indicate a move towards the wood-burning HTA Cell stove and away
from the "pyromid"? I see the "Pyromid" as a companion to the
"charcoal-making stove".

6. I need more votes (although I'm not sure that we can control much); the
stove should have a local language name like "Lakech", "Mirte" etc.).

7. It shouldn't be introduced anywhere without a lot more work and understanding

Regards Ron

(ps. Stovers - You've heard a lot from US contributors today - who have a
day off for our July 4 "Independence Day". This is my last mail today, as
3 grand daughters just arrived for picnic and fireworks).

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From english at adan.kingston.net Fri Jul 4 22:55:50 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:26 2004
Subject: Venturi Burner test
Message-ID: <199707050255.WAA02689@adan.kingston.net>

Dear Stovers

Summary: Venturi Stove tested at less than 100ppmCO with CO2 between
10 and 14%.

We have purchased a CO tester called Monoxor II from Bacharach. It's
range is 0-2000ppm. So I fired up the swirling venturi/cone/pail
arrangement and did some measurements. I didn't test during the first
five minutes. I should have. With a fairly high smoke test of 7 the
CO was around 80-90ppm. This surprised me. There is obviously another
level of testing required to sort out what is plugging the filter of
the smoke tester. As the the burn progressed the smoke reading
declined to about 1 and the CO was as low as 10ppm, with CO2 over
10%. I did not take any temperatures. The stove pipe walls of the
combustion chamber above the venturi glowed orange/red.

Visually the flame dynamic was very good to excellent as the burn
progressed. There were two notable factors which I think
contributed to this result.
1. I used smaller sized fuel pieces, mostly 2*2*13mm cedar. This
may have resulted in a higher gasification rate to better match the
flow requirements of the venturi.
2. I cut holes through the pail just above the bottom of the cone
where the primary air intake is. This eliminated any possible
negative draft associated with the preheating of the primary air in
the pail. As a result I was able to burn well with a shorter chimney.
About 2/3 of what I have used previously.

During the burn I tested the exhaust of a diesel truck, at 425ppm CO.
When the burn went into the charcoal phase the CO went over high end
of the scale, >2000ppm. While CO2 was at 9%.

Afterwards I measured cigarette smoke at 650ppm CO and an oil
furnace (one minute after start up) at 325ppm CO. I will do that
again when I can let the furnace's combustion chamber heat up more.

I hope to do more comparisons to share with the list.

I would be interested in hearing from people experienced in
combustion testing, about methodologies for obtaining accurate
data.

Yours precisely

Alex

Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Fri Jul 4 23:26:40 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:26 2004
Subject: Cone Venturi (English and Hait)
In-Reply-To: <v01540b07afe334a7684d@[204.133.251.5]>
Message-ID: <199707050327.XAA03488@adan.kingston.net>

Dear Ron +

Summary: Response to Ron ; Yes. No.

> (RWL): 1. Alex: In your situation, I think you are always producing
> charcoal (in top-down firing fashion) and that your cone is free of fuel.
> You draw in some more secondary air through the venturi action and complete
> combustion above the venturi. Is this correct?

AE: Yes, except the primary air entering around the outside edge of
the cone consumes the fuel on the outside and the cone falls in
relation to the stationary fuel.

> (Could you also give us a short tutorial on venturis)

AE: No. I am awaiting some information on veturis from our
combustion adviser. He tried to explain it to Brian and I as
balancing an equation of potential and kinetic energies as related to
velocity and pressure. See I told you "no". He also suggested the
optimum angles for the venturi intake slope at 22.5 degrees from
vertical and between 8-15 degrees for the outflow, with a larger
finishing diameter to accommodate the greater volume of gasses. All
this to minimize pressure loss through the total length.
No means no.

Alex
PS Surely some one out there can nail this down for us.
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From ahe1 at cableol.co.uk Sat Jul 5 07:08:54 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:26 2004
Subject: Stove Characteristics (Bess, Moerman, Hait)
Message-ID: <9707051109.AA25270@mars.cableol.net>

Summary - Attempt to address difference in terminology and request for
comment on basic differences of trial stoves

At 18:46 04/07/97 -0600, Ronal wrote:
>Summary - clarification requested on three opinions on top-down
>(charcoal-making) stoves.
>

>Then Etienne said on July 2:
>>>We in Eindhoven agree wholeheartedly. Also we agree that you should not use
>>>the top down approach.
>
> <snip>
>
>And Paul Hait said on July 2 also:
>
>>I agree with both yours and Mike's comments. <snip>
>
>(RWL): I need clarification.
>
>1. Mike: Did you say don't use top down?

(AJH) I read this as being a political statement on the method of
implementing the uptake of more efficient stoves in general i.e. this should
be led by the consumers real needs and not dictated by the
government/organisation maintaining the project. The idea being a more
stable and talented skills base will be in place once support is removed.

I do not think it referred to any attributes of stove operation.
<snip>

>favoring for top-down (charcoal-making) stoves. Without such more
>efficient charcoal production, I think we can expect more widespread
>prohibition of charcoal using stoves.

(AJH) I am with you on this point, I would be grateful on any comments and
references on more efficient and less polluting charcoal making, a member of
the list has pointed me to REUR Technical Series No. 20, 1991
Charcoal Production and Pyrolysis Technologies
Any one else any suggestions?

The necessity to maintain a hot chamber with preheating by propane into
which steam and pyrolysis gases are blown and oxidised, as implemented by
Greg Brown to comply with smoke regulations in Florida, is a short term
solution (kludge?) to pollution where the luxury good ( barbecue charcoal)
can stand the expense but long term the dual use such as Alex's and
Etienne's desighns must be faourable?

Perhaps someone could also corect me on how I visualise the differences on
the three charcoal making experiments, neglecting the very important issues
of gas velocities and grate areas, fine tuning of which is presumably common
to all it looks to me that:

Alex's stove is top lit and primary air enters near the top, the primary
combustion zone, under the cone, travels down as the cone moves down under
its own weight resting on the charge as it settles.

Elsen's stove is top lit with primary air drawn between the two cans above
the charge and secondary air enters alongside the cooking pot, there being
no moveement between the two cans in use

Verhaart construction of Larson-Reed stove is toplit, draws primary air
directly from below cans and charge, with no preheating, secondary air is
via the variable gap between the cans and provision is made to jack up the
fuel into the combustion zone.

This from reading and attempting to understand recent postings and a look at
Alex's pages. Perhaps some schematics could be provided?
AJH

PS Good tea party in the colony?? :-)

From larcon at sni.net Sat Jul 5 07:20:34 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:26 2004
Subject: Venturi Burner test
Message-ID: <v01540b00afe3d2170d31@[204.133.251.2]>

Summary: Questions raised on Alex English procedures in his July 4 message
on pyrolyzing cedar splinters.

Alex said:
> <snip> There is obviously another
>level of testing required to sort out what is plugging the filter of
>the smoke tester.

(RWL): Are there any chemists or chemical engineers on the list who could
analyze the residues and/or describe how to do so?

<snip>
>Visually the flame dynamic was very good to excellent as the burn
>progressed. There were two notable factors which I think
>contributed to this result.
>1. I used smaller sized fuel pieces, mostly 2*2*13mm cedar. This
>may have resulted in a higher gasification rate to better match the
>flow requirements of the venturi.

(RWL): These are very small- approximating straw scraps. Elsen
Karstad reported recently havng no luck with similar small material and I
watched a similar Tom Reed experiment with small pellets - which also was
un-successful. Both I think failed because the path primary air resistance
was too high.

a) Can you think of any reason why you are so successful with this
side -feeding with such small sizes?
b) Have you tried your cone approach with larger branch-sized wood
pieces - as might be found in rural villages?
c) Is there a ready, maybe free supply of this cedar material?
d) What is the approximate conversion efficiency to charcoal?

> 2. I cut holes through the pail just above the bottom of the cone
>where the primary air intake is. This eliminated any possible
>negative draft associated with the preheating of the primary air in
>the pail. As a result I was able to burn well with a shorter chimney.
>About 2/3 of what I have used previously.

(RWL): Is this the same as using a shorter can - or filling the
can further?

<snip>
(Alex) >I hope to do more comparisons to share with the list.
>
(RWL): I hope you can fire up your Paul Hait "Pyromid" for one - with both
commercial briquettes and your own manufactured charcoal. The CO output
from this remains a major unanswered question.

(Alex):
>I would be interested in hearing from people experienced in
>combustion testing, about methodologies for obtaining accurate
>data.

(RWL): Not me - but I also hope someone on the list can add something. It
sounds like maybe we will be asking you about methodologies, as we try this
ourselves.

a) What is the cost of this CO unit?
b) Anyone else know of a favorite competititve CO unit?
c) Congratulations on what sounds like very good news. If we can figure
out why your system works well, a lot of rural scrap biomass material might
open up to effective utilization. That could be very big rural-use news.
I would guess that the resulting charcoal could "only" be used in
briquetting.

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Sat Jul 5 07:20:33 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:26 2004
Subject: Cone Venturi (English and Hait)
Message-ID: <v01540b01afe3db00251e@[204.133.251.2]>

Summary: Question on Venturi operation

In a second message of July 4, Alex said he couldn't explain Venturi action and:

>PS Surely some one out there can nail this down for us.

(RWL):

a. Could you ask your combustion expert for a few references on Venturis
we might read.

b. I'm sure there are list lurkers who can add in here. Being a EE, I
didn't realize that one had to get into "balancing an equation of potential
and kinetic energies as related to velocity and pressure" - so I feel we
are making progress

c. Alex - thanks again for good work, explained well.

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From english at adan.kingston.net Sat Jul 5 07:47:01 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:26 2004
Subject: Venturi Burner test
In-Reply-To: <v01540b00afe3d2170d31@[204.133.251.2]>
Message-ID: <199707051147.HAA10590@adan.kingston.net>

Dear Patient stovers

Summary :CM not MM

Grievous error, late night hustling to get the van ready for Brians
trip.....
I said
>1. I used smaller sized fuel pieces, mostly 2*2*13mm cedar. This
> >may have resulted in a higher gasification rate to better match the
> >flow requirements of the venturi.
I meant- 2*2*13 cm cedar.
These are 1/5 to 1/2 the size of material used on previous tests.

Alex

Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From REEDTB at compuserve.com Sat Jul 5 08:26:01 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:26 2004
Subject: Turbulent & diffusion blue flames
Message-ID: <199707050825_MC2-1A4B-4365@compuserve.com>

Thomas B. Reed 303 278 0558 V Colorado School of Mines
1810 Smith Rd., 303 278 0560 FX Department Chem Eng
Golden, CO 80401 ReedTB@Compuserve.com
ALSO: The Biomass Energy (non-profit)Foundation
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Skip Hayden et al:

Skip says that "blue" does not necessarily mean low CO emissions. I have
studied stove, bunsen, welding and other flames - but not from the emission
viewpoint - for 40 years. My impression is that the blue flame temperature
is high enough so that any CO-H2 not burned in the inner cone will burn
where the outer flame contacts the air.

Typically blue flames from methane, kerosene, etc. devices are tolerated
indoors with no ventilation. There is no warning on the stoves about CO.
How come?

Do you have data to the contrary, in which case I retract my "blue flame"
statement.

Thanks, TOM REED

From REEDTB at compuserve.com Sat Jul 5 08:26:00 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:26 2004
Subject: Charcoal lighting
Message-ID: <199707050825_MC2-1A4B-4358@compuserve.com>

All this talk of charcoal brings up the subquestion of lighting.

The Pyromid uses one small stick of lighter and is ready to cook in 6
minutes. My two sons use large quantities of smoky lighter fluid and are
ready to cook in 20 minutes. What do they do everywhere else? Is lighting
a long process? Does it use a lot of "starter"?

What about starting real charcoal vs starting briquettes?

Just asking, TOM REED

From skip.hayden at cc2smtp.NRCan.gc.ca Sat Jul 5 09:28:47 1997
From: skip.hayden at cc2smtp.NRCan.gc.ca (Skip Hayden)
Date: Tue Aug 31 21:35:26 2004
Subject: Turbulent & diffusion blue flames
Message-ID: <9706058681.AA868120104@cc2smtp.nrcan.gc.ca>

Re: Tom Reed's comments/questions:

A significant number of CO poisonings in the U.S. come from
gas ranges. This happens sometimes during a cooking
operation, but often occurs in (but is not limited to)
lower income housing where the range is being used as an
additional heating source. It might indeed be a good idea
to have a cautionary sticker about CO on these appliances,
or at least to recommend fan hoods with good fans exhausting
outdoors when they are being used.

As well, in general, when the combustion process of natural
gas is disturbed for one reason or another, the first
indication of incomplete combustion is carbon monoxide,
without particulates, even though the flame is still
primarily transparent, while with oil, the first indication
is soot (i.e. particulates).

With wood burning systems, the secondary combustion zone,
still usually within the same combustion chamber, and often
coming back in contact with the primary flame, does get a
chance to burn the CO and volatile hydrocarbons, but
depending on the mixing, the secondary/tertiary air preheat
and the time (sound familiar), you can still get high levels
of CO.

We developed a blue flame oil burner some years ago which
had a beautiful almost transparent flame, had very intense
swirl and low NOx. Its one drawback was that under
transient conditions, it was very susceptible to CO.

Hope this helps,

Skip Hayden
Senior Research Scientist
Advanced Combustion Technologies
Ottawa, Canada K1A 1M1
TEL: (613) 996-3186
FAX: (613) 992-9335
e-mail: skip.hayden@cc2smtp.nrcan.gc.ca

From english at adan.kingston.net Sat Jul 5 10:42:34 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:26 2004
Subject: More;Venturi Burner test
In-Reply-To: <v01540b00afe3d2170d31@[204.133.251.2]>
Message-ID: <199707051442.KAA13884@adan.kingston.net>

Dear Ron + Stovers

I have loaded a drawing, with some discription, of the venturi burner
onto the web page. Hope it helps.

I did test the Pyromid with briquettes as fuel. CO was higher that
2000ppm. CO2 at around 8%. The Pyromid has since left with the Burt's
on their vacation.

I did some more testing of our oil furnace. It is quite old. At 11%
CO2 , 500ppm CO. At 8% CO2, 100ppm CO. These tests were done after
the combustion chamber had reached normal operating temperatures.

The Monoxor II CO tester cost $589 USD.

Alex
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Sat Jul 5 12:02:01 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:26 2004
Subject: Charcoal lighting
In-Reply-To: <199707050825_MC2-1A4B-4358@compuserve.com>
Message-ID: <199707051602.MAA15777@adan.kingston.net>

Dear Tom +

Summary: Charcoal is faster.

I have only starters a few fires with the Pyromid but I was able to
start a charcoal fire with little pieces of twisted paper lit below
the charcoal. I think it took 3 or 4 minutes. My one try with
briquettes and the starter candles took at least ten minutes. I need
to watch the watch more . It will have to wait till August when the
Pyromid returns.

Alex

Tom R. wrote>
> All this talk of charcoal brings up the subquestion of lighting.
>
> The Pyromid uses one small stick of lighter and is ready to cook in 6
> minutes. My two sons use large quantities of smoky lighter fluid and are
> ready to cook in 20 minutes. What do they do everywhere else? Is lighting
> a long process? Does it use a lot of "starter"?
>
> What about starting real charcoal vs starting briquettes?
>
> Just asking, TOM REED
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Sat Jul 5 12:02:03 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:26 2004
Subject: Pyromid Improved ?&#~!
In-Reply-To: <199707041546.IAA15241@butch.transport.com>
Message-ID: <199707051602.MAA15780@adan.kingston.net>

Dear Paul +

The "product" which shall remain nameless, has cooked meals, easily,
for as many as 13 of my relatives. These relative who are not prone
to polite positive reviews where all delighted with their food. As
chef I found it easy to use. I even used the downward heat by leaning
the burger buns up against the bottom supporting pyramid. Efficiency
rose dramatically.

I would agree that "Fuel organization" or its relationship to air
flow and chamber geometry is key. My experiments focus on this. Now I
need to see what happens when I stop having a dropping cone and go to
under grate primary air supply. My design thoughts are moving away
from charcoal-making batch fires towards a regularly tended fire.

Alex

> >Dear Alex,
>
> Sorry for the slow response. I hope you like the product? Your pictures that
> you have put of the web is a great contribution. Good job! Your suggestion
> is our Pyromid enclosed Campfire. We need to stay in touch as you use your
> Pyromid 15. Hopefully, you can see the effects of fuel organization? What do
> you think?
>
> Sincerely,
> Paul
>
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From elk at arcc.or.ke Sat Jul 5 12:52:05 1997
From: elk at arcc.or.ke (Elsen L. Karstad)
Date: Tue Aug 31 21:35:26 2004
Subject: can Mk1
Message-ID: <m0wkY3u-0006XoC@arcc.or.ke>

In partial answer to a few questions Ron poses (4/7/97);

>(RWL): a. Is this a transferrable container (easy in / easy out) to allow
>also for snuffing of the charcoal?
>b. Any reason for the 1.3 cm gap? (convenient can size?)
>c. Do you think the radial temperature variation is now less? (because the
>inner cylinder achieves a higher temperature?)
>d. I don't see why there should be any difference in the "even-ness" of
>the air flow (except maybe due to better radial temperature uniformity).
>e. How tight was the sealing at the top of this new inner cylinder? (It
>would seem that you need complete separation of the lower pyrolysis chamber
>from the upper combustion chamber.) And how was this sealing obtained?

elk:

a) yes, though I've yet to finalise the extraction tool- maybe a semicircle
wire with hooked ends fitting through perforations. Charcoal still poured
out & covered in dirt to snuff. An airtight receptacle for this fuel
container will be made anon for snuffing.

b) No reason for this gap size- that was the gap I asked for, the gap is
actually a touch over 2 cm. on measurement. I wanted free flow of air around
the container.

c) I'm sure the radial temperature variation is less. One of the problems
with the orig. stove was partial carbonisation of wood in contact with the
inner stove walls. This is no longer the case.

d) See above.

e) Not sure I understand your question. The pyrolisis container placed
within the pyrolisis chamber of the stove is open at the top, 2 cm below the
level of the secondary air inlet ring. Could you amplify on what your mental
picture of the container is? I'm intrigued.

RWL;

>a). Sounds like a very good approach to controlling primary air -
>but maybe expensive to produce?.
> b). Do you think this was the main reason for now getting a 3:1 turndown
>ratio? (you have some very large maximum air holes).
>c). When you were running at maximum and minimum power level, about how far
>open were these openings?
>d) Do you think with this arrangement that you might get away with just
>one single opening? Maybe with a horizontal slide?
>e) Do you think you could reduce the 6 cm bottom gap (to save height and
money)?
>

elk:

a) Not expensive, the spring in the steel is produced by tempering a strip
of red hot sheet metal in sump oil. What I don't like about it is that the
three vents are removable and hence 'loseable'.

b) The improved turndown ration is, I think, due to both the increased
control using the V-shaped primary air venting and the even pyrolisis
produced via the perforated fuel container.

c) Minimum power (at mid burn) was when 2cm of the 'V' was exposed - from
the bottom. The 'V' shaped primary air opening is 6 cm high and 4 cm accross
the top. Maximum power was probably less than 'wide open', though I didn't
note carefully. I will in future trials. I felt that wide open settings
would result in open flame in the lower areas of the fuel chamber. My
approach to this is better to much air than too little for the initial fuel
lighting.

d) A single opening would be O.K. I think- maybe some sort of baffling in
the space below the fuel chamber ('fuel cell'?) would be in order if only
one valve is used in order to avoid uneven pyrolisis in the cell.

e) Again, yes, probably down to 4 cm- that would fit in with horizontal
slides. Maybe a Jiko type hinged door or two would be applicable, I've
always been impressed with their tight fit, though the metal is extremely
thin & flexible.

RWL;

>a) What weight of wood can you now use?
>b) Are you still using an outer wind screen?
>c) What is the spacing between pot and combustion chamber?
>d) The pot is 14 cm high?
>e) How supported?

a) Ave loading is 5 kg dry brown olive hardwood branches ave. 5 cm diam. lit
with paper & kindling on top. I was impressed by how much easier it is to
light vertically standing wood as opposed to horizontally placed sections.

b) Yes- as pictured in Alex's web site. Secondary air enters the bottom of
this outer shield- not the top. There is no wind screening for primary air
vents.

d) 9 mm to 1 cm. gap between pot & stove.

e) Yes, 14 cm high.

f) The pot has a 2.5 cm wide rim. This rests on the top of the stove. 50% of
the stove has been bent away in 5 cm deep by 5 cm wide notches to allow
exhaust gasses to escape.

The flame attachment is motile- variable around the secondary air inlet
ring. The almost complete absence of smoke indicates fairly complete
combustion of volatiles. These are all outdoor tests & we've had some gusty
weather here in Nairobi recently. In addition, it is difficult to see much
of what goes on in the combustion chamber with the pot inserted into the top
of the stove. I can only assume that the stove performs differently with the
pot removed. I look at boiling vigour and smoke to ascertain performance.
The addition of a fuel chamber seems to have 'smoothed out' all parameters,
and as the insert is 2 cm below and ~2 cm distant from the secondary air
inlet, it seems not to interfere with the flame attachment. Since the fuel
'cell' is made of 3mm perforated steel and is 2cm away from the sides of the
pyrolisis chamber inner wall, I think that volatiles exit the sides of the
cell to rise up in this gap to the heated secondary air inflow where
ignition occurs.

What type of insulation indeed? Cement? Several stovers have scrounged
around this part of the globe.... suggestions?

Iv'e taken the 'turbo' out of this stove now.

My vote for a name for the final product is 'Charcoal Making Stove' - CMS
for short, but until we are all satisfied with the final product, lets feel
free to name experimental models what we will. Local dialectic names are an
obvious marketing requirement in some areas.

All the best;

elk

From elk at arcc.or.ke Sat Jul 5 12:53:47 1997
From: elk at arcc.or.ke (Elsen L. Karstad)
Date: Tue Aug 31 21:35:26 2004
Subject: Charcoal lighting
Message-ID: <m0wkY3s-0006XkC@arcc.or.ke>

Tom;

I light my charcoal making stoves with paper and kindling (twigs), and
usually get a flame up to cooking heat within 3 minutes.

For the local charcoal, as most stoves use a grate or perforated ceramic,
the charcoal is placed on a bed of twigs on top of the grate, and lit from
beneath with paper, or better yet, waxed paper 'tetrapack' milk carton. This
creates a lot of smoke initially, but lights quickly, with charcoal evenly
lit in approx 5 minutes. This procedure is normally performed outside, and
the stove brought into the home once smoke has ceased.

Note the need for insulated handles on stoves.

elk

At 08:25 05-07-97 -0400, you wrote:
>Thomas B. Reed 303 278 0558 V Colorado School of Mines
>1810 Smith Rd., 303 278 0560 FX Department Chem Eng
>Golden, CO 80401 ReedTB@Compuserve.com
>ALSO: The Biomass Energy (non-profit)Foundation
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Dear Elsen et al:
>
>All this talk of charcoal brings up the subquestion of lighting.
>
>The Pyromid uses one small stick of lighter and is ready to cook in 6
>minutes. My two sons use large quantities of smoky lighter fluid and are
>ready to cook in 20 minutes. What do they do everywhere else? Is lighting
>a long process? Does it use a lot of "starter"?
>
>What about starting real charcoal vs starting briquettes?
>
>Just asking, TOM REED
>
>

From tmiles at teleport.com Sat Jul 5 18:33:57 1997
From: tmiles at teleport.com (Tom Miles)
Date: Tue Aug 31 21:35:26 2004
Subject: Bioenergy Email Lists and Commands
Message-ID: <3.0.32.19970705151205.00eef54c@mail.teleport.com>

BIOENERGY EMAIL LISTS

The bioenergy mailing lists are hosted by the Center for Renewable Energy &
Sustainable Technologies(CREST) for industry, academia and government to
discuss biomass production and conversion to energy. There are five lists
at CREST.

o Bioenergy <bioenergy@crest.org>
Moderator: Tom Miles <tmiles@teleport.com>
(Other Volunteers are Welcome!)
Archive:
<http://solstice.crest.org/renewables/bioenergy-list-archive/>
Digest: bioenergy-digest@crest.org

o Gasification <gasification@crest.org>
Moderators: Thomas Reed <REEDTB@compuserve.com>
Estoban Chornet <Chornete@tcplink.nrel.gov>
Archive: <http://www.crest.org/renewables/gasification-list-archive>
Digest: gasification-digest@crest.org

o Anaerobic Digestion <digestion@crest.org>
Moderators: Phil Lusk <plusk@usa.pipeline.com>
Pat Wheeler <patrick.wheeler@aeat.co.uk>
Richard Nelson <rnelson@oz.oznet.ksu.edu>
Dave Stephenson <cdstephenson@tva.gov>

Archive: <http://www.crest.org/renewables/digestion-list-archive>
Digest: digestion-digest@crest.org

o Stoves (stoves@crest.org)
Moderators: Ronal Larson <larcon@csn.net>,
Etienne Moerman <E.Moerman@stud.tue.nl>
Archive: <http://www.crest.org/renewables/stoves-list-archive/>
Digest: stoves-digest@crest.org

o Bioconversion <bioconversion@crest.org>
Moderators: Tom Jeffries <twjeffri@facstaff.wisc.edu>
Archive:
<http://www.crest.org/renewables/bioconversion-list-archive/>
Digest: bioconversion-digest@crest.org

Current subscribers to the lists are engaged in the research and commercial
production of biomass crops and fuels, the conversion of biomass power in
commercial operating plants, the construction and testing of commercial
scale pilot facilities for combustion, gasification and anaerobic
digestion, testing and analysis of environmental impacts for bioenergy, and
promotion and planning of future bioenergy resources.

This is a cooperative, volunteer effort that is now in it's third year. The
lists are moderated and managed by volunteers. We appreciate the support of
the Center for Renewable Energy and Sustainable Technologies and the
National Bioenergy Industries Association for hosting the lists at their
site.

CONTRIBUTIONS

While there is no fee to subscribe to the lists contributions are welcome
($100 minimum please) and will be necessary to sustain the lists. Please
contact CREST <zach@crest.org>.

COMMANDS

To subscribe to the BIOENERGY Lists from any internet email address, please
send email to MAJORDOMO@CREST.ORG with the message

SUBSCRIBE list-name YOUR EMAIL ADDRESS <=three word command
(Example: subscribe bioenergy tmiles@teleport.com)

To post a message to all members on the list, please address it to
list-name@CREST.ORG
(Example: bioenergy@crest.org)

UNSUBSCRIBE list-name YOUR EMAIL ADDRESS <=three word command
(Example: unsubscribe bioenergy tmiles@teleport.com)

Note: If you send a subscribe/unsubscribe command for an email address that
is different from the one known to the list server - for example, you may
send a subscribe command on behalf of someone else - then your message will
go to the list moderator for approval.

OTHER COMMANDS - Send email to MAJORDOMO@crest.org with the command 'help'.

MESSAGE ARCHIVE
Messages are archived at CREST using hypermail. The archives can be viewed
and sorted by date, subject or thread using a WWW browser at URL
<http://solstice.crest.org/renewables/bioenergy-list-archive/index.html> (or
as indicated above). CREST (Solstice) also supports WWW, gopher and ftp
for renewable energy at Solstice@crest.org.

MESSAGE DIGEST
Each list also has a digest, a collection of messages that is issued
periodically. This may be useful if you want to receive messages in a batch.
Subscribe to the list-name-digest@crest.org as indicated above.
(Example: subscribe gasification-digest@crest.org)

World Wide Web
~~~~~ ~~~~ ~~~
<http://solstice.crest.org/>

Gopher
~~~~~~
gopher.crest.org

Anonymous FTP
~~~~~~~~~ ~~~
solstice.crest.org

You can contact CREST at +1 202 289-5370,
or by sending email to info@crest.org.

LISTS ADMINISTRATORS
Please direct questions to the bioenergy list administrators:
Tom Miles, Jr. tmiles@teleport.com,
Zach Nobel zach@crest.org

------------------------------------------------------------------------------
Thomas R. Miles, Jr. tmiles@teleport.com
Technical Consultant Tel (503) 292-0107
5475 SW Arrowwood Lane Fax (503) 292-2919
Portland, Oregon, USA 97225-1353

From phait at transport.com Sat Jul 5 23:04:17 1997
From: phait at transport.com (John Doe)
Date: Tue Aug 31 21:35:26 2004
Subject: Charcoal lighting
Message-ID: <199707060255.TAA24631@butch.transport.com>

>Dear Tom +
>
>Summary: Charcoal is faster.
>
>I have only starters a few fires with the Pyromid but I was able to
>start a charcoal fire with little pieces of twisted paper lit below
>the charcoal. I think it took 3 or 4 minutes. My one try with
>briquettes and the starter candles took at least ten minutes. I need
>to watch the watch more . It will have to wait till August when the
>Pyromid returns.
>
>Alex
>
>Tom R. wrote>
>> All this talk of charcoal brings up the subquestion of lighting.
>>
>> The Pyromid uses one small stick of lighter and is ready to cook in 6
>> minutes. My two sons use large quantities of smoky lighter fluid and are
>> ready to cook in 20 minutes. What do they do everywhere else? Is lighting
>> a long process? Does it use a lot of "starter"?
>>
>> What about starting real charcoal vs starting briquettes?
>>
>> Just asking, TOM REED
>>
>>
>Alex English
>RR 2 Odessa Ontario
>Canada K0H 2H0
>613-386-1927
>Stoves Web Site http://www1.kingston.net/~english/Stoves.html
>Dear Tom,
Thankyou for the Pyromid plug!
When you make Charcoal it is top down lighting(TDL). When you light Charcoal
it is bottom up lighting(BUL). The reason why Pyromids light so quickly
should be obvious. The Igniter is backed up by a reflector(foil liner). The
briquette array is above the igniter. The briquettes are black and absorb
the heat of the igniter very quickly. Any hot briquette will drive the one
next to it (Thermal Feedback).As long as there is feeder air from the holes
in the foil liner everything is perfect for rapid charcoal or briquette
ignition. On the other hand, the Weber is a black energy absorbing body that
has a random pile of briquettes in it. The briquettes are saturated with
liquid fire liter to get them ignited. This is a brut force way to light
briquettes. Very inefficient and polluting. Actually in a Weber you are top
down lighting the briquettes;thus 20 minutes to get the briquettes going.
Also you are using 20,000 BTU's to cook six Hamburgers. This is wasteful and
makes very little sense. We know you can cook the same number of Hamburgers
in a 12 inch Pyromid with only 2250 BTU's or 9 briquettes. With our SUPER
HEAT INSERT put into the Weber you can eliminate the need for liquid fire
liter all together and reduce the consumption of briquettes by up to 75%. We
are going to push this product for introduction into the LA Basin.It is
patented.
You must remember that when the Gas Grill people brag about 20,000 BTU
grills they are also over killing and polutting the environment. Their sales
argument for switching from 20,000 BTU Webers( 80 briquettes) to 20,000 BTU
Gas Grills is that they are faster,cleaner ,and more convenient. They fail
to mention new hazards,just as much wasted energy, poorer flavor, higher
cost,and more regulations.
When Charcoal is ignited and burned in a physics principaled structure it is
safer,less polluting,faster cooking,imparts a better flavor to the food( if
no liquid fireliter is used)and burns for a long period of time( HTA Cell)
at a lower cost.
Hopefully, you have experienced the Pyromid charcoal burning principal
enough to respect the amount of cooking that can be done with a few number
of well placed briquettes. Alex seems to believe in what we are doing also.

Have a great summer and enjoy your Pyromid!

Sincerely,
Paul Hait
phait@transport.com

From larcon at sni.net Sat Jul 5 23:58:47 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:26 2004
Subject: Charcoal lighting
Message-ID: <v01540b02afe4c33bac9a@[204.133.251.2]>

Summary: Top lighting also of charcoal (as well as charcoal-making) stoves.

Today, Tom, Alex, and Elsen (and maybe Paul Hait earlier) all have
described (I think) bottom lighting of charcoal stoves. Because of the
absolute need to top-light a charcoal-making stove, I have experimented
with lots of top-lighting starting materials and have settled on the dry
fallen needles of the Ponderosa pine - about 10 cm long and all over my
property.

When starting Paul's "Pyromid" (and earlier), I have "naturally"
continued top lighting the same way and find it works very well. Like
Alex, I havn't timed it and will now do so.

The advantages of pine "straw" are: free, rapidly and easily
ignited and quick speading flames, very loose- allowing smoke release, and
they can break up into the crevices of the charcoal. Top lighting seems
easier - to arrange the fuel first and then add the starter material and
light it last.

It probably is slower to get all the charcoal fully lit, but maybe
one doesn't want the bottom part fully lit anyway??

More later when I do more timing.

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Sat Jul 5 23:58:51 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:26 2004
Subject: can Mk1
Message-ID: <v01540b01afe4ad6b8c6d@[204.133.251.2]>

Summary: Continuing dialog on Karstad's Mk I charcoal making stove -
especially on a perforated fuel container.

>>(RWL):
>>e. How tight was the sealing at the top of this new inner cylinder? (It
>>would seem that you need complete separation of the lower pyrolysis chamber
>>from the upper combustion chamber.) And how was this sealing obtained?

(ELK):
>e) Not sure I understand your question. The pyrolisis container placed
>within the pyrolisis chamber of the stove is open at the top, 2 cm below the
>level of the secondary air inlet ring. Could you amplify on what your mental
>picture of the container is? I'm intrigued.

(RWL): Your original statement was :
>>>Insertion of a perforated steel container in the pyrolisis chamber (same
>>>height, narrower) allowing for a 1.3 cm gap between chamber wall and
>>>pyrolisis container. Primary air flow restricted entering the preforated
>>>>bottom of this container only.

When I read this first sentence, I thought the entire container was
perforated. When I read this second, I decided only the bottom was
perforated.

Below you state: > Since the fuel
>'cell' is made of 3mm perforated steel and is 2cm away from the sides of the
>pyrolisis chamber inner wall, I think that volatiles exit the sides of the
>cell to rise up in this gap to the heated secondary air inflow where
>ignition occurs.
So now it is clear that your whole "fuel cell" is perforated.

Now, what I had in mind was a removable "cell" that had a rim at the top to
keep it from falling down to the bottom. This sealed the lower space from
the upper. The reason for having this design in mind was having built one
in late 1995 in Harare, Zimbabwe that worked pretty well (perforated only
at the bottom, not perforated everywhere) in the one day I had to test it
before I left Harare. The secondary air was half way up this same "fuel
cell" and one controlled both primary and secondary air with the same three
lower plugs. This was built using an existing commercial "Tsotso" ("bits
and pieces") stove with a lot of external (vermiculite?) insulation.
Since you were describing a separate secondary air inlet, I still
assumed a lip but also assumed separate fuel and combustion regions.

Question a) How do you support the fuel container in a centered
manner and at the desired (6 cm) height from the bottom? (if not with my
assumed lip)
b) What is the perforation size and spacing?

A few comments on your full "fuel cell" perforations: I think this
is a great innovation - I would have never tried this.

I have had a mental image of needing to have complete isolation of
the fuel - using a solid metal wall - mainly to achieve the vertical
pressure distribution that I thought necessary. What I now think is
happening in your design is a little different from your description. I
believe primary air might also ENTER through the side perforations - as
well as "Primary air flow restricted entering the preforated bottom of
this container only." The question is on the (very slight) radial pressure
differences (in the fuel region) - that I think might allow a substantial
amount of primary air to enter through the side perforations.

I do agree "that volatiles exit the sides". If this were not the
case, I believe you would be combusting the charcoal above the
downward-moving pyrolysis zone. It would be interesting to see if you are
getting some combustion and flame holding on the perforated wall. If not,
then you are at least getting some premixing and this is presumably
helpful.

One key to better understanding this new perforation parameter
would be to be able to better look at what is happening. Tom Reed did this
at NREL (SERI?) with a large Pyrex glass container. Several small sections
of Pyrex (or something) might also work to allow a view of what is
happening here. Maybe a piece of flexible glass rod(s) (as used by
physicians) would also allow us to better see what is happening.

Another would be some modeling (sounding like a broken record).

(Elsen):
>a)I was impressed by how much easier it is to
>light vertically standing wood as opposed to horizontally placed sections.

(RWL): Maybe this is another example of Paul Hait's "harmonic array" ideas
- In both cases, air flow and radiation are efficiently used. With
horizontal pieces of fuel, the air flow is much harder to achieve and the
radiation can't strike the lower opposite fuel pieces,

(Elsen): >d) 9 mm to 1 cm. gap between pot & stove.

(RWL:) - maybe a few mm of insulation will also help you get closer to the
"convection" recommendation from Etienne.

New possibility: You might consider doing something more like the
"Tsotso" modification described above. In which both the (perforated) fuel
cell and the (maybe non-perforated) upper combustion chamber are both
removed together. The main advantage would be achieving the wind shield
more easily,

Again - I'm not sure about exactly what is happening in detail,
but I really like your idea of a perforated container - now knowing that it
works. Great work!

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From english at adan.kingston.net Sun Jul 6 23:20:20 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:26 2004
Subject: Pseudo Data
Message-ID: <199707070320.XAA28143@adan.kingston.net>

Dear Stovers

Summary: More CO Tests

To correct for various excess air factors in testing the different
appliances the manual says to multiply the CO measurement by
20.9/(20.9-O2). I use the rough equivalent (for low CO readings) of
20.9/CO2.
For the 'pseudo' data below, AR -means ' As read', ADJ - means
'adjusted' as above. Numbers refer to ppm CO.

Kerosene Lamp AR - 51, ADJ-266
Coleman Lamp (burns naptha) AR-75, ADJ 209
Propane Fridge (not premixed) AR-17, ADJ-89
Propane Stove AR-17, ADJ -118
Oil fired Boiler (fired at 12 USGPH with a fairly advanced burner)
AR-15, ADJ-26
Rapid Fire in a Box Stove ; for this test I made a 'log
cabin' array of air dry Cedar 1 by 4 (2*8cm) and 1 by 2 (2*4) inside a
simple box stove, with the door shut and air supply open. It fired
quickly up to a maximum rate which lasted only a few minutes. During
this peak there was an even shorter lived minimum CO reading of,
AR-300, ADJ- 522. The whole burn lasted only twenty minutes. A
reading taken 5min into the burn was AR-700, ADJ- unavailiable .
During the declining five minutes readings rose steadily. Approximate
AR-1250, ADJ- 3265.

I am eager to test the best model of the top-down gasifiers that
Elsen, Ron and Tom have made.I tried to make one yesterday, with
mixed results. Using a 18cm pipe with about 30- 6mm holes drilled
just above the fuel. The pipe sat on a grid of wire where bottom air
could enter. I controlled it's supply with sand. Suspended an apple
juice can, partly full of water, in the top. There was about 5cm all
around the can which made it easy to observe. It had moments of glory
with flames attached to all the air holes, and extending somewhat
horizontally to the centre where they rose rapidly to the bottom of
the boiling can. During these moments there was no visible smoke.
During one smokeless moment I obtained CO readings around AR-1200,
ADJ-3100. Nothing about this stove was optimized so these readings
should be mostly ignored .

Ron would you outline specifically, instructions for building a stove
like this and obtaining a "best" result based on your experience. A
set of drawings for the web page would be nice.

Alex

Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From larcon at sni.net Sun Jul 6 23:44:02 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:26 2004
Subject: Stove Characteristics (Heggie)
Message-ID: <v01540b00afe5e5479a2f@[204.133.251.1]>

Summary - My attempt to address Andrew Heggie's "Attempt to address
difference in terminology and request for comment on basic differences of
trial stoves" (plus a bit on flaring of large charcoal-making kilns)
>

Point #1: Andrew on 5 July was responding to my comments of July 4, and said:

<snip>
>(AJH) I read this as being a political statement on the method of
>implementing the uptake of more efficient stoves in general i.e. this should
>be led by the consumers real needs and not dictated by the
>government/organisation maintaining the project. The idea being a more
>stable and talented skills base will be in place once support is removed.
>
>I do not think it referred to any attributes of stove operation.

(RWL): Andrew - I now think you are right. I blew it and apologize to
all. In case not everyone has followed this exchange closely enough,
Etienne said:
" >>you should not use the top down approach"
and I took this to mean:
"you should not use a charcoal-making approach"
Andrew - thank you - I shall try to avoid such narrow minded thinking again
(and I support having a lot of local input in both the design and decision
making). I will try to switch to the terms "top-lighting" and "top-lit".

Andrew's Point 2:
>(AJH) <snip> I would be grateful on any comments and
>references on more efficient and less polluting charcoal making, a member of
>the list has pointed me to REUR Technical Series No. 20, 1991
> Charcoal Production and Pyrolysis Technologies
>Any one else any suggestions?

(RWL): I don't believe that any part of this handbook dealt with flaring.
Is that correct? Last May 1, I speculated on various ways to turn a
metal ring charcoal-kiln into a flaring device (and can send this to anyone
interested). I continue to think this is a valuable topic for this group
for these five reasons:

1. Flaring is of interest to Andrew, Greg Brown, and a few others on the
list - and is of major importance in global warming - and flaring doesn't
seem to be now practiced in the field anywhere.

2. There are some similarities to charcoal-making stove operation and we
can perhaps learn from the millenia of charcoal kiln operation.

3. The charcoal output of these kilns is needed for the charcoal-using
stoves we have much discussed recently.

4. There is no other list which is apt to tackle this problem.

5. If flaring were perfected, we would probably see more use of the
flared gas valuable energy in places like bakeries, ceramics kilns,
brickmaking, etc.)

(AJH):
>The necessity to maintain a hot chamber with preheating by propane into
>which steam and pyrolysis gases are blown and oxidised, as implemented by
>Greg Brown to comply with smoke regulations in Florida, is a short term
>solution (kludge?) to pollution where the luxury good (barbecue charcoal)
>can stand the expense but long term the dual use such as Alex's and
>Etienne's designs must be favourable?

(RWL): In many developing countries (as expressed on this list recently by
Elsen Karstad and Mike Bess - and others earlier), a very high percentage
of the urban cooking is done with charcoal (not much being either luxury or
barbecueing).

I believe that with top-lit firing of the metal kiln, one can avoid
the big difficulty of an initial period of much moisture release as the
entire fuel stock is dried out. If someone could test top-lit flaring with
a large metal charcoal kiln, I believe some major advances would result.

Andrew's Discusion Point #3:
A. >Perhaps someone could also correct me on how I visualise the differences on
>the three charcoal making experiments, neglecting the very important issues
>of gas velocities and grate areas, fine tuning of which is presumably common
>to all it looks to me that:
>
>Alex's stove is top lit and primary air enters near the top, the primary
>combustion zone, under the cone, travels down as the cone moves down under
>its own weight resting on the charge as it settles.

(RWL): I would modify this a little to say that I believe that both
primary (see definition below) and part of the secondary air enters near
the bottom (outer edge) of the inverted moving cone. There is a
significant amount of charcoal production as well in Alex' design, so one
needs to talk about both a combustion zone (outer edge of falling cone) and
a pyrolysis zone (everywhere else). In this design, a large part of the
secondary air is drawn in near the tip of the invertd cone using Venturi
device, with a lot of the combustion above the venturi. There are no
bottom, primary air holes in Alex approach. (Alex?)

(AJH-B):
>Elsen's stove is top lit with primary air drawn between the two cans above
the charge and secondary air enters alongside the cooking pot, there being
>no movement between the two cans in use.

(RWL): No. I wouldn't agree with this (at least using my understanding of
the term "primary air" - which I take to be the air used in pyrolysis).
This primary air is all coming up from the very bottom - moving against the
pyrolysis zone (which moves downward). The gases above the pyrolysis zone
contain no oxygen, until the secondary air (not the primary air) comes in
(" drawn between the two cans above the charge"). I believe that one can
normally achieve complete combustion before a small amount of additional
secondary air is drawn in near the pot. In general, I think we want to
avoid this additional secondary air. (Elsen?)

(AJH-C):
>Verhaart construction of Larson-Reed stove is toplit, draws primary air
>directly from below cans and charge, with no preheating, secondary air is
>via the variable gap between the cans and provision is made to jack up the
>fuel into the combustion zone.

(RWL): I think this is basically correct - with the exception that
maybe the "jacking up" should refer only to raising finished charcoal
(certainly not the original wood fuel) "into the combustion zone". (Piet?)

(AJH):
>This from reading and attempting to understand recent postings and a look at
>Alex's pages. Perhaps some schematics could be provided?
>AJH
>
>PS Good tea party in the colony?? :-)

(RWL): It was. (For some non-Brits and non-Americans, we should say that
the American Revolution was largely symbolized by a protest ("party")
against a British tea tax). As I watched the more peaceful transfer of the
Hong Kong colony the previous week (with much better fireworks that ours!),
I was struck by some of the parallels.

Andrew - thank you for raising three important points.
Question - in both pit charcoal making and metal ring charcol kilns
- it seems to me that almost all air introduced (especially after drying)
can be called "primary air" - and none is secondary air. If the pyrolysis
gases are flared - all the air needed to do that would be called "secondary
air" Does this sound OK for the charcoal kiln community?

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Sun Jul 6 23:44:54 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:26 2004
Subject: CO production (Reed and Hayden)
Message-ID: <v01540b02afe605c63c9e@[204.133.251.1]>

Summary: Raising some additional questions for Skip Hayden on CO production.

On July 5, Skip Hayden responded to an earlier message from Tom Reed, saying:

> A significant number of CO poisonings in the U.S. come from
> gas ranges. This happens sometimes during a cooking
> operation, but often occurs in (but is not limited to)
> lower income housing where the range is being used as an
> additional heating source. It might indeed be a good idea
> to have a cautionary sticker about CO on these appliances,
> or at least to recommend fan hoods with good fans exhausting
> outdoors when they are being used.

<snip>

(RWL): 1. Skip - Do some or most of these tragedies occur as the oxygen in
the room is depleted?
2. Since most third world stove rooms are much less tight, should
this be a smaller problem overseas?
3. Can you extend a parallel to combustion of both charcoal and
the pyrolysis gases coming from charcoal making - rather than (natural) gas
or oil or wood ranges.
4. Have you ever measured the CO emissions from charcoal-burning
stoves - and can you guess as to why CO emissions are or could be higher
from such stoves? (and how to minimize the emissions?)

Thanks and regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From english at adan.kingston.net Mon Jul 7 07:08:03 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:26 2004
Subject: Turbulent & diffusion blue flames
In-Reply-To: <9706058681.AA868120104@cc2smtp.nrcan.gc.ca>
Message-ID: <199707071108.HAA02693@adan.kingston.net>

Dear Skip

Summary; Why?
Skip wrote:
> We developed a blue flame oil burner some years ago which
> had a beautiful almost transparent flame, had very intense
> swirl and low NOx. Its one drawback was that under
> transient conditions, it was very susceptible to CO.

What is meant by transient conditions? Was it more "susceptible" than
the modern " flame retention" oil burners? If so, why?

>
> Hope this helps,

Sharing your knowledge of combustion has been, and will be, very
helpful.

Alex

> Skip Hayden
> Senior Research Scientist
> Advanced Combustion Technologies
> Ottawa, Canada K1A 1M1
> TEL: (613) 996-3186
> FAX: (613) 992-9335
> e-mail: skip.hayden@cc2smtp.nrcan.gc.ca
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Mon Jul 7 07:08:03 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:26 2004
Subject: CO production (Reed and Hayden)
In-Reply-To: <v01540b02afe605c63c9e@[204.133.251.1]>
Message-ID: <199707071108.HAA02696@adan.kingston.net>

Dear Stovers
Summary; Propane oven test shows one mechanism for high CO

While taking the readings referred to in the email ' Pseudo Data' the
propane oven cycled (off-on-off) due to thermostat. The CO the as
read readings were reached maximums of 5 to 8 times what the readings
were during the burner was on. The Monoxor II tester can sample
continuously with about a 5 sec delay. The Bacharach Fyrite CO2
tester takes a manually pumped 40sec average sample with a necessary
time out inbetween samples. As a result I cannot take accurate CO2
measurements of rapidly changing conditions as during the start and
stop portion of the propane oven. This means I cannot adjust the CO
reading to a common "Air free" denominator. That said, it seems that
the oven cycling could add considerably to CO levels in a closed
dwelling.

Alex
>
>
> On July 5, Skip Hayden responded to an earlier message from Tom Reed, saying:
>
> > A significant number of CO poisonings in the U.S. come from
> > gas ranges. This happens sometimes during a cooking
> > operation, but often occurs in (but is not limited to)
> > lower income housing where the range is being used as an
> > additional heating source. It might indeed be a good idea
> > to have a cautionary sticker about CO on these appliances,
> > or at least to recommend fan hoods with good fans exhausting
> > outdoors when they are being used.
>
> <snip>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From elk at arcc.or.ke Mon Jul 7 08:22:51 1997
From: elk at arcc.or.ke (E. L. Karstad)
Date: Tue Aug 31 21:35:26 2004
Subject: clarification - 2can mk1
Message-ID: <v01510100afe67a32d7b4@[199.2.222.151]>

>(AJH-B):
>>Elsen's stove is top lit with primary air drawn between the two cans above
>the charge and secondary air enters alongside the cooking pot, there being
>>no movement between the two cans in use.
>
>(RWL): No. I wouldn't agree with this (at least using my understanding of
>the term "primary air" - which I take to be the air used in pyrolysis).
>This primary air is all coming up from the very bottom - moving against the
>pyrolysis zone (which moves downward). The gases above the pyrolysis zone
>contain no oxygen, until the secondary air (not the primary air) comes in
>(" drawn between the two cans above the charge"). I believe that one can
>normally achieve complete combustion before a small amount of additional
>secondary air is drawn in near the pot. In general, I think we want to
>avoid this additional secondary air. (Elsen?)

Correct. The pot is inserted into the 'chimney' of the stove, with the gap
between stove and pot venting exhaust gas only. This is the only apparent
function and intent. Primary air from below toplit fuel, pre-heated
secondary air from a few cm above the top of the fuel (measured before
lighting).

Trying to maintain a simplistic 'two-can' approach, I have not considered
the injection additional secondary air at any other level. From my
observations, it should not be necessary.

I'll get a sketch of the modified 2can mk1 (soon to be mk3 at this rate)
off to Alex before my holiday break on the 17th.

Rgds;

elk

_____________________________
Elsen Karstad
P.O Box 24371 Nairobi, Kenya
Tel:254 2 884437
E-mail: elk@arcc.or.ke
______________________________

From skip.hayden at cc2smtp.NRCan.gc.ca Mon Jul 7 09:41:50 1997
From: skip.hayden at cc2smtp.NRCan.gc.ca (Skip Hayden)
Date: Tue Aug 31 21:35:26 2004
Subject: Turbulent & diffusion blue flames
Message-ID: <9706078682.AA868293675@cc2smtp.nrcan.gc.ca>

Alex:

By transient conditions, I mean start-up and shut-down, especially the
former with regards to CO production and the blue flame burner. A
typical residential oil burner undergoes somewhere between 3000 and
6000 cycles over the heating season. The initial conditions on
start-up, where the oil is released below final design pressure and
the air pattern (and draft) is not fully established, leads to
significant amounts of incomplete combustion products, like CO and
soot. Modern, high static (eg Riello-type) flame retention head
burners tend to hold the oil longer and have more intense mixing, so
that this condition is not so pronounced.

With the blue flame burner, it is much more difficult to "tame" this
initial unstable condition due to the lack of radiant heat in a
transparent flame, etc.. One German blue flame burner (MAN) tried to
get around this by running at fairly high excess air to start with,
and then automatically closing down the air once equilibrium was
established.

Hope this helps,

Skip Hayden
Senior Research Scientist
Advanced Combustion Technologies
ETB/CETC
Ottawa, Canada K1A 1M1

TEL: (613) 996-3186
FAX: (613) 992-9335
e-mail: skip.hayden@cc2smtp.nrcan.gc.ca

______________________________ Reply Separator _________________________________
Subject: Re: Re[2]: Turbulent & diffusion blue flames
Author: stoves@crest.org at internet
Date: 7/7/97 7:54 AM

Dear Skip

Summary; Why?
Skip wrote:
> We developed a blue flame oil burner some years ago which
> had a beautiful almost transparent flame, had very intense
> swirl and low NOx. Its one drawback was that under
> transient conditions, it was very susceptible to CO.

What is meant by transient conditions? Was it more "susceptible" than
the modern " flame retention" oil burners? If so, why?

>
> Hope this helps,

Sharing your knowledge of combustion has been, and will be, very
helpful.

Alex

> Skip Hayden
> Senior Research Scientist
> Advanced Combustion Technologies
> Ottawa, Canada K1A 1M1
> TEL: (613) 996-3186
> FAX: (613) 992-9335
> e-mail: skip.hayden@cc2smtp.nrcan.gc.ca
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From skip.hayden at cc2smtp.NRCan.gc.ca Mon Jul 7 09:51:45 1997
From: skip.hayden at cc2smtp.NRCan.gc.ca (Skip Hayden)
Date: Tue Aug 31 21:35:26 2004
Subject: CO production (Reed and Hayden)
Message-ID: <9706078682.AA868294276@cc2smtp.nrcan.gc.ca>

Ron:

I'll try and answer your four questions in order:

1. It seems that most of the CO poisonings from gas ranges are not due to
exhaustion of O2 in the room - that is to say, not due to the room being
particularly tight and the available O2 being used up and finally CO2/N2 being
the "combustion air". In most cases, it is due to improper adjustment of the
burners themselves.

2. My answer to the first question would indicate that the leaky rooms of third
world countries may not help them very much, as the CO is due to improper
combustion. The build-up of CO in the room might be lower, but the CO levels
emitted from biomass stoves are likely to be higher yet, so the net effect could
be the same. Also, to a fair degree, tightness and air change rate are not
interchangeable, so that even a leaky room/house can have a low air change rate
and rapid build-up of indoor pollutants.

3. I guess I have already answered this in 2. Certainly the exact shape and
placmenet of the biomass fuel, the biomass fuel quality and the draft imposed
upon the combustion will have varying effects on the amount of CO from biomass
stoves, although they will always tend to be significantly higher than for gas
ranges.

4. Charcoal stoves will naturally tend to have higher levels of CO and lower
levels of other incomplete combustion products, especially lower volatile
hydrocarbons, because the volatiles in the biomass have already been driven off
in the production of the charcoal. Depending on the stove design, it is
important to create a window and hot zone where the CO can be ignited and
completely combusted to CO2. This is easier said than done. With wood stoves,
the volatile hydrocarbons are much easier to ignite and provide the conditions
necessary to get rid of the CO. Having said this, it is still certainly doable
with some care, some preheated air and an insulated secondary combustion zone.

______________________________ Reply Separator _________________________________
Subject: Re: CO production (Reed and Hayden)
Author: stoves@crest.org at internet
Date: 7/7/97 8:21 AM

Summary: Raising some additional questions for Skip Hayden on CO production.

On July 5, Skip Hayden responded to an earlier message from Tom Reed, saying:

> A significant number of CO poisonings in the U.S. come from
> gas ranges. This happens sometimes during a cooking
> operation, but often occurs in (but is not limited to)
> lower income housing where the range is being used as an
> additional heating source. It might indeed be a good idea
> to have a cautionary sticker about CO on these appliances,
> or at least to recommend fan hoods with good fans exhausting
> outdoors when they are being used.

<snip>

(RWL): 1. Skip - Do some or most of these tragedies occur as the oxygen in
the room is depleted?
2. Since most third world stove rooms are much less tight, should
this be a smaller problem overseas?
3. Can you extend a parallel to combustion of both charcoal and
the pyrolysis gases coming from charcoal making - rather than (natural) gas
or oil or wood ranges.
4. Have you ever measured the CO emissions from charcoal-burning
stoves - and can you guess as to why CO emissions are or could be higher
from such stoves? (and how to minimize the emissions?)

Thanks and regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From E.Moerman at stud.tue.nl Mon Jul 7 10:07:30 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:26 2004
Subject: Mike Bess on Charcoal and Stove Characteristics
Message-ID: <14870.s335192@popserver.tue.nl>

Paul Hait:

> equation at my company. I want people in general to recognize that by
> organizing energy in an HTA Array in a cell they can use the energy both up
> and down. I use one briquette( Kingsford type)~250 BTU's according to Tom
> Reed, to cook for one person. How many BTU's did your stoves use to cook for
> one person?
> Is your 20% fire using the heat under the fire as well as above? Was the
> wood organized TEEPEE style? How much of the fire did the pot cover? How
> high was the pot over the fire? Was the fire indoors(no wind) or outdoors?
> Was the fire in a hole with a ring of rocks, or was it on a flat surface?Was
> it shielded so the heat would be more focused? What was the time interval to
> peak heat and how long did it stay that way with out refueling? Was the wood
> layed randomly? Was there a lot of pitch in the wood? Considering the
> scarcity of wood in the third world it seems to me that your tests should
> have been done with dung,Acacia,Mesquite,Gum,Corn Cobs, etc.The wood you
> used sounds like it came from a fuel plentiful area. Sorry for all the
> questions, but I still think that the average outdoor fire using different
> types of woods at different moistures in a black hole with a ring of rocks
> is much less efficient than 20%.
> In a sealed box your % efficiency sounds right if the heat is only used on
> top of the box.

Etienne:
I am sorry, but these are too many questions for me to answer since I did
not do the studies on open fire and shielded fire myself. Of course I did a
few quick experiments just to get a feel for these configurations. First of
all I have no comments on your stove, since I have not seen it. I am not
able to get graphics from the web, just text, so I don't know how it looks
like. I expect to be able to have a look at some later time.
I did only one cooking test. It was with the shielded fire and I
described it in detail about a year ago on this stoves list, see archives. I
cooked 1 kg of rice with I think 2 kg of water. I cannot find the original
data, but I think that around 450 gr. of White Fir (10% moisture) was used
to cook the rice, that should be about 7.2MJ (I don't know the BTU's like
this). It was the first time, so during the experiment I got the
feeling that I could do a lot better than that in later experiments. I
expect that I can get below 400 gr. of wood (10% moisture) for 1 kg. of
rice.
By heat under the fire I assume the you mean the thermal radiation from
the char. Although I never did any efficiency measurements with the open fire
I guess it did contribute to the pan. The fuel consisted of wood blocks
about 20x20x25mm, so I don't think it was organized. The fire was indoors,
no wind. The fire was on a flat surface. I don't think it was shielded.
nothing. I don't know the answers to your other questions.
Regarding the efficiency in the field I agree that it is often below 20%,
but we tend to believe that most so-called improved stoves have efficiencies
below 20% in the field.

Paul Hait:
> efficiency statements come from using the heat both up and down. Are we
> doing something wrong from the stove researchers point of view?

Etienne:
As long as you are measuring efficiencies with the water boiling test, both
below and on top you are not doing anything wrong. It would be recommendable
however to present all efficiencies eg. on top, at the bottom and combined
(can be done in 1 experiment). If the performance of the stove is seriously
affected by the absence of a pan on top or at the bottom you should also
give the efficiencies for a single pan on top and at the bottom (2
experiments). By the way if you are doing water boiling tests a lid on the
bottom pan might not be appropriate, providing that you use it for baking or
drying. As far as space heating is concerned everything that does not go
strait up the chimney is useful and efficiencies for space heating can be as
high as 90-100%.

Paul Hait:
> It was interesting to see that you do not remember stove names. What was the
> name of your favorite stove? In your opinion what is the best concept in the
> world today? To many questions I know,but your knowledge is invaluable to
> the Stovers.

Etienne:
My favourite stove is the downdraft stove, but that is not useful for
cooking. However it is expected to be very useful for medium-scale power
requirements like baking, waste incineration and brick kilns.
The best concept for the world doesn't exist. As far as efficiency is
concerned I think that the shielded fire and variations on it are the best
performers and dead cheap. However as was discussed on the list a few days ago
efficiency is not that important to the user. I don't think that a woodstove
presently exists that meets the first 3 criteria that were mentioned.
By the way thanks for the compliments.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Mon Jul 7 10:07:33 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:27 2004
Subject: Pyromid and/or HTA Cell Stove (Paul Hait)
Message-ID: <14878.s335192@popserver.tue.nl>

> (RWL): 1. Whew - glad I don't have to answer all those questions.
> 4. The wind shield you described as mine must go back much further - I
> like the analysis of that shield done by Sam Baldwin in his thesis. Anyone
> ever seen any experimental validation?

Etienne:
I don't know on what topic you need experimental validation, but in Paul
Bussmann's thesis the shielded fire is discussed at length. Both from an
experimental and a theoretical point of view.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Mon Jul 7 10:07:42 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Bess, Moerman, Hait)
Message-ID: <14885.s335192@popserver.tue.nl>

Andrew Heggie:
> solution (kludge?) to pollution where the luxury good ( barbecue charcoal)
> can stand the expense but long term the dual use such as Alex's and
> Etienne's desighns must be faourable?

Etienne:
I think you are giving me unjust credit. I have the impression that you are
talking about charcoal making stoves and I did not do anything with or for
those stoves.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Mon Jul 7 10:07:50 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:27 2004
Subject: Venturi Burner test
Message-ID: <14881.s335192@popserver.tue.nl>

Alex:
> I would be interested in hearing from people experienced in
> combustion testing, about methodologies for obtaining accurate
> data.

Etienne:
Always give the CO/CO2 ratio and always calibrate daily before starting
experiments. Also use filters and cool down gas flow to avoid damage to
electtronic meters. We have a combined CO/CO2 meter (electronic based on
infrared absorption measurements) and a O2 meter (electronic based on
paramagnetic properties of O2). We filter the sampled gases with a
cottonwool filter, then with filtration paper, then with a microfilter and
finally we pass it through an ice chamber. If you don't do this the meters
get damaged after some time by soot and tar deposits and by water
condensation. We calibration each day that we do experiments we use N2 and a
calibration gas with a composition that we specify when we by the gas and
that is exactly determined with a gas chromotograph.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Mon Jul 7 10:07:48 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:27 2004
Subject: Charcoal lighting
Message-ID: <14888.s335192@popserver.tue.nl>

Thomas Reed:

> The Pyromid uses one small stick of lighter and is ready to cook in 6
> minutes. My two sons use large quantities of smoky lighter fluid and are=
>
> ready to cook in 20 minutes. What do they do everywhere else? Is lighti=
> ng
> a long process? Does it use a lot of "starter"? =

Etienne:
It is all a matter of experience and patience. At the start it took me 20 min.
too, but now I also manage the 6 min. For convenient and fast lighting we
sometimes used a few blocks of wood that were soaked in kerosene for an hour
or so or a bunsen burner. However fine pieces of wood and some medium sized
wood is all you need (and a match or lighter of course).

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Mon Jul 7 10:07:59 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Bess, Moerman, Hait)
Message-ID: <14875.s335192@popserver.tue.nl>

> (RWL): I need clarification.
>
> 1. Mike: Did you say don't use top down?
>
> 2. Etienne: What are your (Eindhoven) reasons for being opposed to top
> down (charcoal-making) stoves?
>
> 3. Paul: In something you wrote a while back, I thought I heard a
> favoring for top-down (charcoal-making) stoves. Without such more
> efficient charcoal production, I think we can expect more widespread
> prohibition of charcoal using stoves.

Dear Ron,

I think you are working too hard :-). Unless I misunderstood myself we were
not talking about your stove, but about stove dissimenation programmes. Too
many stove programmes in the past introduced stoves that did not solve the
users major problems. The top that never cooks with a woodstove designed the
stove (without listening to the user) and tried to promote it among the
people that cook with wood daily. Since the designers this way did not solve
the problems that were important to the user these stove programmes failed.
If you want to know my objections to some parts of your stove I suggest that
you have a look at the archives. We discussed this in the past at length and
there is no use in repeating these discusions.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Mon Jul 7 10:07:55 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:27 2004
Subject: More;Venturi Burner test
Message-ID: <14891.s335192@popserver.tue.nl>

Alex English:

> I did test the Pyromid with briquettes as fuel. CO was higher that
> 2000ppm. CO2 at around 8%. The Pyromid has since left with the Burt's
> on their vacation.

Etienne:
Your CO2 is too low. You should try to adjust your air supply to keep the O2
roughly between 5 and 9 %, so your CO2 11-15%. In our downdraft these ranges
give the lowest CO, obviously halfway the interval was best.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From mike at esd.co.uk Mon Jul 7 12:40:22 1997
From: mike at esd.co.uk (Mike Bess)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove price
In-Reply-To: <v01540b05afdd74faa043@[204.133.251.16]>
Message-ID: <EtKAp1A6ARwzUA2n@esd.co.uk>

Dear Juan Carlos,

I apologise for the delay in responding to your e-mail. Let me clarify
that I have been speaking of two types of stoves in Ethiopia; the first
is called the "Lakech" (can mean "splendid", "beautiful"), and the
"Mirte" (which can mean "better"). The lakech is an improved charcoal
stove that incorporates a ceramic liner set into a thin metal housing.
The Lakech has sold 300,000 stoves over the past five years while the
Mirte is entering its third year of commercial sales and has sold over
17,000 stoves.

The Mirte may be of more interest to you than the Lakech. It is
designed to burn wood, branches, leaves, sawdust and most other biomass
(it does not burn dung efficiently). It is made from a mixture of
cement and various other building materials (pumice, scoria, sand,
etc.). It is made in six pieces using two moulds. It retails at about
3.5 or US$ 5.00 to 5.50 in most areas.

The Mirte incorporates a "mtad" which is a traditional ceramic plate
that is used to bake "injera", the traditional Ethiopian flat bread. It
has certain similarities to tortillas, to Indian chapatis, except it is
made from a pancake like batter, which is poured on the plate and
cooked. The typical housewife cooks 30 injeras in one session, and must
cook twice a week.

One of the fascinating things about the Mirte and its commercialisation
is that it is very popular with commercial injera bakers. There are
several photos now up on the "stovers" Web site, which could give you
more of a pictorial view. The commercial bakers sell injera to other
households, to restaurants, hotels, bars, etc. Some commercial bakers
bake over 300 injera a day per stove, working for over 15 hours, often
employing several other women, to bake over 1,000 injeras per day.

The Mirte reduces wood consumption by about half in actual household
practice, and even more in commercial cooking circumstances. It reduces
smoke considerably, which is why most cooks prefer it. It also protects
them from the flames. It is clean. These are all features which make
it popular.

I hope this answers some of your questions. All the best, Mike Bess,
mike@esd.co.uk
--
Mike Bess

From mike at esd.co.uk Mon Jul 7 13:03:02 1997
From: mike at esd.co.uk (Mike Bess)
Date: Tue Aug 31 21:35:27 2004
Subject: Mike Bess on Charcoal and Stove Characteristics
In-Reply-To: <199707011452.HAA23497@butch.transport.com>
Message-ID: <UNEEB6AATRwzUAWo@esd.co.uk>

phait wrote:
>I have found the above write up to be one of the most brilliant reviews I
>have read yet. Congratulations on all your hard work! Please contact me
>directly at phait@transport.com. I believe that my HTA Cell principles could
>be applied to your cast stoves. Additionally,I have a local company here in
>Oregon that has developed a unique light weight fire proof cement like
>material that would be great for your stoves. The material could be made in
>africa or shipped since it is as light as a feather. When combined with
>local materials it sets up into a rock hard material that has extremely high
>fire resistance. It is used for fire door material here in the states.

mike bess:

We would be very interested to learn more about your HTA cell principle.
You say it can be produced locally. This is of critical importance to
the Mirte biomass stove in Ethiopia, and, indeed, stoves in most of the
developing world. The margins on profit on production and sales of
stoves are so small, than any imported components almost always
increases the cost beyond the means of most consumers, and almost always
makes the stoves less competitive compared with other tradtional
options. We have had to make designs that enable a variety of local
materials to be used to keep costs down and to make the whole production
process less complicated (which is also very important). Cheers, Mike

paul hait wrote:
>I find your Charcoal facts to be very interesting also. Are there any
>Briquette operations in Kenya or Ethiopia? I have found that by arranging
>Briquettes in what I call a Harmonic Thermal Array I can get much higher
>temperatures quicker with much less fuel( 75% less). I also take advantage
>of the the heat radiating down as well as up. Do your Stoves do this? How
>can we work together? Check out our site at http://www.estore.com.
>
mike bess:

There is one commercial briquetting operation in Kenya which carbonises
coffee husks and sells the briquettes to higher income consumers. It is
called "kahawa (coffee)" charcoal, and has been around for at least
fifteen years. It is 50% or more expensive than the "traditional"
charcoal found locally. It has a niche market for people who believe
they are doing something for the environment.

A major briquetting project was funded by the DANIDA (Danish aid)
through the World Bank in Ethiopia for briquetting from cotton husks,
from coffee husks, from crop residues. No commercial charcoal
briquettes have been produced from this top-down (socio-technical)
approach which did not involve the private sector, and which involved
expensive imported equipment. A commercial briquette manufacturer
operated in Ethiopia for several years, but stopped due to low charcoal
prices. The same experience has been repeated in Uganda and several
other countries, with the same results for the same reasons.

My own opinion: Briquettes are an extremely expensive solution to world
fuel supply. They are economic where there is a surplus of "waste"
material, where transport costs are low, AND (most important of all)
there is a market. Most briquettes do not burn well in traditional
charcoal stoves. Many binders are positively noxious (try the smell of
burnt molasses and sulpher in an enclosed room if you don't believe it),
and consumers have little cost or other incentives to buy briquettes
(the briquettes are alien, etc.). Where briquettes might work is with
captive markets and, again, where costs of raw materials are negative
(ie, they are a burden to get rid of), where transport costs are near
zero, and where there is a market. Cheers, Mike
--
Mike Bess

From mike at esd.co.uk Mon Jul 7 13:09:58 1997
From: mike at esd.co.uk (Mike Bess)
Date: Tue Aug 31 21:35:27 2004
Subject: Plancha Stove (J. Flores)
In-Reply-To: <199707011509.IAA23615@butch.transport.com>
Message-ID: <ddYGF9AxbRwzUAWB@esd.co.uk>

Dear Juan Carlos,

I apologise for coming into the group late, and not being familiar with
all that has been said before. I am interested in your plancha stove
because it has many similarities to other high mass stoves that try to
address the issues of improved wood burning. You wrote:

>JCF> The consumption with the plancha stove is about 20%
>less than in the non-improved woodstove, and the consuption per day
>is 65.64 Kg. The people use the woodstove about 10-12 hors per day,
>the time use depend in the work of the people. For exempla if the
>person make "tortillas" (a kind of food that is made of corn) they
>use the woodtove about 12 hours per day. The rates of consumption are
>from 93 Kg/week to 39.5 Kg/week. The different is big because there
>aren't a stadistic control, so in some cause the woman cook for more
>than 6 person and she has to make torillas. The women that make
>tortillas make more than 1200 tortillas per day, and they have to
>cook all the day. In another case the people don't have the enough
>education for using the woodstove, and they don't use the woodstove
>in the right way. This is a very important point, because if we want
>the people use the improved woodstove, we have to training them, and
>to explain them Why they have to use the new woodstove.

My question is "how do you guarantee quality control of the plancha
stove to maintain efficiencies, and how do you commercialise of
disseminate it to a wide audience"? The reason I ask, is that our
experience is that without standardisation of high mass stoves, which is
always a problems with self-made stoves, quality, consequently
efficiency, varies dramatically. Also, self-made stoves are not
interesting to most urban women who prefer to pay for their fuel and the
stoves that burns the fuel. But, even if you can manage to work
intensively with women who make the stove, how do you expand production
and dissemination to tens of thousands of households and cooks and still
maintain quality and efficiency?

I ask these questions because we faced the same problems and we found
that we had to standardise the stove in order to reach larger numbers
and to keep efficiencies high. This requires some form of mass
production. As Etienne and others have noted, simply enclosing an open
fire can easily dramaticallay improve efficiencies; so does good
practice and husbandry. But, we know that not everyone is a good cook,
and not everyone will mind a stove in the best way. So, to remove this
people variation factor, we believe there must be standardisation that
allows for very little variation in actual use. I would be interested
to learn of your experiences.

All the best, Mike (mike@esd.co.uk)

--
Mike Bess

From ahe1 at cableol.co.uk Mon Jul 7 13:19:30 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Heggie)
Message-ID: <9707071719.AA14623@mars.cableol.net>

Summary: Ronal has all my respect for his work on this list and I am still
looking for published literature plus some comments on autopyrolizing of
bone dry wood.

>(RWL): Andrew - I now think you are right. I blew it and apologize to
>all.
I am glad I was able to point out the misunderstanding, certainly no need to
apologize especially in view of the work you have taken on in keeping up
with the postings.

>
>(RWL): I don't believe that any part of this handbook dealt with flaring.
>Is that correct?
(AJH) I have only recently requested details, no chance of a responses yet.
<snip>
(AJH)points 1-4 agreed

> 5. If flaring were perfected, we would probably see more use of the
>flared gas valuable energy in places like bakeries, ceramics kilns,
>brickmaking, etc.)
(AJH) Yes this is what I most want to try, probably as an adjunct to
woodburning in view of David Beedie's comments on the production curve of
gases in a batch loaded gasifier.

>
>(RWL): In many developing countries (as expressed on this list recently by
>Elsen Karstad and Mike Bess - and others earlier), a very high percentage
>of the urban cooking is done with charcoal (not much being either luxury or
>barbecueing).
(AJH) My point exactly, intuitively there must be surplus heat available its
just how do we tap it?
>
> I believe that with top-lit firing of the metal kiln, one can avoid
>the big difficulty of an initial period of much moisture release as the
>entire fuel stock is dried out. If someone could test top-lit flaring with
>a large metal charcoal kiln, I believe some major advances would result.

(AJH) Greg is trying this, I am trying to persuade my co workers to load one
kiln with uniform 2-10cms cordwood vertically stacked and top lit as per the
stoves, attitudes are hard to change when production bonuses are at stake!

(RWL)> Question - in both pit charcoal making and metal ring charcol
kilns
>- it seems to me that almost all air introduced (especially after drying)
>can be called "primary air" - and none is secondary air. If the pyrolysis
>gases are flared - all the air needed to do that would be called "secondary
>air" Does this sound OK for the charcoal kiln community?

(AJH) Agreed, without testing equipment I am not sure what part if any of
the pyrolisis gases are oxidised in the kiln, I suspect your analysis is
correct and hence the air used is primary, by your definition, and as no
secondary air is available and the gases are in a moisture laden stream
which inhibits combustion then they are vented with inevitable environmental
consequences. I am still interested to hear what others think of the idea
propounded by Tom Reed that bone dry wood might autopyrolise. This should
have the benefit of evolving a gas of higher calorific value than the lean
gas of a gasifier as no primary air would be needed and hence there would be
no nitrogen to carry away sensible heat or dilute the calorific value.
AJH

From mike at esd.co.uk Mon Jul 7 14:10:02 1997
From: mike at esd.co.uk (Mike Bess)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Bess, Moerman, Hait)
In-Reply-To: <v01540b04afe31dd20ae2@[204.133.251.5]>
Message-ID: <gdCJlDBZ5RwzUARy@esd.co.uk>

Dear Ron,

When I said "top down" I was referring to a developmental, social,
political approach in which people from outside or from some place that
is supposed to know it all, come in from the top and try to get people
who are "below" or "down" to take up their approach. This fails, and
has been the result of many failures in stove projects and other
"appropriate" or "intermediate" technologies over the past years.
Cheers, Mike
--
Mike Bess

From ahe1 at cableol.co.uk Mon Jul 7 14:22:19 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Bess, Moerman, Hait)
Message-ID: <9707071822.AA30857@mars.cableol.net>

At 04:08 07/07/97 +0100, you wrote:

>Etienne:
>I think you are giving me unjust credit. I have the impression that you are
>talking about charcoal making stoves and I did not do anything with or for
>those stoves.
Yes my mistake, too many new names on my screen, I meant Elsen.
AJH

From mike at esd.co.uk Mon Jul 7 15:13:23 1997
From: mike at esd.co.uk (Mike Bess)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Heggie)
In-Reply-To: <v01540b00afe5e5479a2f@[204.133.251.1]>
Message-ID: <be23lGBJDSwzUAnL@esd.co.uk>

>Andrew's Point 2:
>>(AJH) <snip> I would be grateful on any comments and
>>references on more efficient and less polluting charcoal making, a member of
>>the list has pointed me to REUR Technical Series No. 20, 1991
>> Charcoal Production and Pyrolysis Technologies
>>Any one else any suggestions?

mike bess replies:

The Overseas Development Institute (ODI) through the British ODA, did
some very interesting work on improved charcoal production and released
that during the 1980s. I will try to extract some references in the
next few days. Also, please look at the work that Derek Earle has done
back originally with the FAO, later with the ODA, on improving charcoal
production, the Casamance Senegal kiln, etc. Again, I will try to bring
up some materials. Derek did some work under USAID's "Sudan Renewable
Energy Project" in the mid-1980s, particularly studying "traditional"
production techniques, which Ron Larson might be familiar with...

>
>(RWL)
> 1. Flaring is of interest to Andrew, Greg Brown, and a few others on the
>list - and is of major importance in global warming - and flaring doesn't
>seem to be now practiced in the field anywhere.
>
> 2. There are some similarities to charcoal-making stove operation and we
>can perhaps learn from the millenia of charcoal kiln operation.
>
> 3. The charcoal output of these kilns is needed for the charcoal-using
>stoves we have much discussed recently.
>
> 4. There is no other list which is apt to tackle this problem.
>
> 5. If flaring were perfected, we would probably see more use of the
>flared gas valuable energy in places like bakeries, ceramics kilns,
>brickmaking, etc.)
>
We are very interested in anything going on in improving charcoal
production in the developing world. We believe that charcoal use will
not disappear any time soon. It can be produced sustainably in the
developing world, and a combined approach that tackles improved charcoal
production and charcoal use can achieve very significant local results
and contribute positively to climate change. Governments who rely on
kerosene to substitute for charcoal spend hundreds of millions of
dollars every year for a short-term "solution" and one that does not
address fundamental issues of sustainable energy production and
consumption. Moreover, hundreds of thousands of people in the
developing world depend on charcoal (production, transport, sales) for
their livelihoods. It is a major income generating source for
government. It should be recognised for what it is, one of the major
energy sources in the developing world, and one whose efficiency can be
improved.....

Just a few thoughts for the day! mike
--
Mike Bess

From elk at arcc.or.ke Mon Jul 7 15:28:33 1997
From: elk at arcc.or.ke (Elsen L. Karstad)
Date: Tue Aug 31 21:35:27 2004
Subject: Trial results- 2can mk1 (modified)
Message-ID: <m0wlJPu-0006bQC@arcc.or.ke>

Stovers- good news today;

It seems that the fiddly fine-tuning is paying off. The perforated fuel cell
insert has improved performance, if not efficiency, remarkably.

Today's results:

-Wood and water weights were both matched at 4.72 kg

-Time to evaporate water completely: 1 hr 25 min.

-Time to bring water to vigourous boil: 9 minutes after top lighting with
small dry twigs.

-Charcoal produced: 700 gm (18% of initial wood weight)

-Total burn time: 1 hr 25 min.

Note that time to total water evaporation and total burn time are the same.
The flame in the combustion chamber did not extinguish itself at the point
of complete pyrolisis but continued in response to a very slight opening of
primary air vents. Upon removing the pot to refill, I saw that pyrolisis was
complete and the charcoal was being consumed. This surprised me, as I had
assumed that charcoal alone would not support a flame in the combustion
chamber as observed. It explains the low charcoal yield though.

Turndown ratio: 4 to 5. This stove configuration is incredibly responsive
while consistantly holding a flame in the combustion chamber over the
complete range of primary air settings.

No smoke at any time during the entire burn (after lighting). Full power
during mid-burn produced some soot and a very large amount of heat.

Upon achieving a boil the primary air vents were closed completely and only
opened a fraction toward the very end of the trial, when, as it now is
evident, the pyrolisis was complete. A controlled simmer was achieved and
maintained. Water boiled evenly accross the bottom and around the sides of
the pot.

I was surprised that a flame could be maintained in the combustion chamber
for over one hour with the primary air vents completely closed. These vents
seal very well. Air from the secondary vent slit must circulate down and
into the side of the perforated fuel cell.

Flame attachment was fairly even and most pronounced at the 15 points where
the secondary air slit had been bent open from 4mm to 1 cm. Toward the end
of the burn the flame darkened noticeably to purple and even blue in places.
I have opened a small aperature (1cm sq.)in the side of the stove at the
level of the bottom of the pot which allows me to observe the interior of
the combustion chamber. This seems to have little or no effect on the
funtion of the stove.

Charcoal was extinguished by 'fishing' the entire fuel cell out of the stove
with hooked wire and sealing it in a 25 kg paint tin for 10 minutes.

Over the next couple of days I'll run a few more trials with an aim to
extending cooking time and the amount of water evaporated, and to collect
some baseline data prior to attempting to insulate.

Glad to hear you're cooking on a 2can now Alex. I'm beginning to think I
need some help on this!

'Till next time;

elk

From elk at arcc.or.ke Mon Jul 7 15:37:31 1997
From: elk at arcc.or.ke (Elsen L. Karstad)
Date: Tue Aug 31 21:35:27 2004
Subject: No Subject
Message-ID: <m0wlJbT-0006bVC@arcc.or.ke>

Mike Says;

>Dear Ron,
>
>When I said "top down" I was referring to a developmental, social,
>political approach in which people from outside or from some place that
>is supposed to know it all, come in from the top and try to get people
>who are "below" or "down" to take up their approach. This fails, and
>has been the result of many failures in stove projects and other
>"appropriate" or "intermediate" technologies over the past years.
>Cheers, Mike
>--
>Mike Bess

Well, how about a Down to Up approach then? All we need is some serious
enthusiasm from the 'Down' crowd. The Ups can be educated into support after
development and initial market proofing, not before.

I see no great difficulty here.

elk

From larcon at sni.net Mon Jul 7 15:52:52 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:27 2004
Subject: Top-lit designs (English request)
Message-ID: <v01540b00afe6bd61e7b0@[204.133.251.2]>

Summary - This letter offers a rationale for procrastination in a request
from Alex English for "instructions for building a (top-lit,
charcoal-making) stove"

On July 6, Alex English said:

>I am eager to test the best model of the top-down gasifiers that
>Elsen, Ron and Tom have made.I tried to make one yesterday, with
>mixed results. Using a 18cm pipe with about 30- 6mm holes drilled
>just above the fuel. The pipe sat on a grid of wire where bottom air
>could enter. I controlled it's supply with sand. Suspended an apple
>juice can, partly full of water, in the top. There was about 5cm all
>around the can which made it easy to observe. It had moments of glory
>with flames attached to all the air holes, and extending somewhat
>horizontally to the centre where they rose rapidly to the bottom of
>the boiling can. During these moments there was no visible smoke.
>During one smokeless moment I obtained CO readings around AR-1200,
>ADJ-3100. Nothing about this stove was optimized so these readings
>should be mostly ignored .
>
>Ron would you outline specifically, instructions for building a stove
>like this and obtaining a "best" result based on your experience. A
>set of drawings for the web page would be nice.

(RWL):
1. On January 3 and 6 of 1996, before there was a "stoves" list, I sent
out instructions on the "bioenergy" list. I have sent out quite a few
more since to people who requested them. I would be delighted to send more
out again - but think I shouldn't repeat them on this list until having a
chance to redo them, in light of several new results that have been given
on this list - especially from Elsen Karstad.

2. Anyone having tried those instructions from 18 months ago would help
me a great deal by explaining (on-list or off-list) successes or failures
in their modifications of the design.

3. I would now recommend persons wanting to try this type of stove to use
the design that Elsen is testing - which is much more of a cook stove than
the science fair type demonstration experiment which was in the early 1996
discussions. There is a great deal to be gained from making variations -
and hope that everyone will try both Elsen's design and any small
variation. My questions below illustrate some of the urgently needed
variations.

4. Questions for Alex:
a. Your use of a wire mesh at the bottom and sand for primary air supply
control is the type of variation that we need to see more of. Did you feel
it was satisfactory? I have tried something similar with dirt used for
controlling the secondary air supply (for snuffing) and a "pipe" to feed
the primary air; I'm not very happy with that design. Elsen's use of
concrete provides physical stability (while making a cheap air seal) - and
is a direction I want to test next.

b. In your 18 cm diameter design with 30 secondary air holes (6 mm
dia), I would recommend a larger number of smaller holes - maybe even a
slit. But I really haven't studied this enough. Before you scrap your
first model, I hope you can add more secondary air holes in the 12 mm space
between your existing secondary air holes.

c. I would like to know the heights of your fuel/pyrolysis section and
your combustion section. I think the height of the combustion section is
most critical - needing to be at least as tall as the diameter - and
perhaps even 50% larger. This needs a lot more study.

d. You mentioned using "pipe". Was this ordinary stove pipe (which
comes flat and can be quickly and easily "snapped" into a pipe shape)? I
think this may be a good design choice (being cheap and widely available in
a wide range of diameters). I have used cans only because they are free
and have a nice closed bottom. They are not tall enough and they are not
very stable. Using Elsen's idea of concrete makes the stove pipe more
attractive.

e. You didn't mention wind screen - which is urgently needed for outdoor
cooking. I am really intrigued by Elsen's use of perforated metal for the
fuel container (as it apparently greatly improves the uniformity of
charcoal production near the fuel container wall). There are a lot of
ideas that can be tested with this. Perhaps the perforations can be
extended all the way up through the combustion region - where the upper set
of holes are perhaps used to hold insulation in place.

f. I'd like to hear more about your fuel. I believe vertical round
branches work a lot better than "square" samples, because the latter can
mesh too closely together and prevent (or slow down) pyrolysis.

g. I'd like to hear a lot more from you and others about flame holding.
I think there are many materials we can use that will help do better on
this important aspect.

h. I think there are some things you might suggest near the secondary
air holes that would be like your Venturi designs - to improve mixing and
turbulence (if those are helpful).

Good luck. Obviously, this type of stove will benefit from lots more
imaginative development - and you have a big advantage in your CO/CO2
measurement capabilities.

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Mon Jul 7 18:43:25 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Heggie)
Message-ID: <v01540b03afe70fe60eae@[204.133.251.5]>

Mike Bess said today:

> Derek did some work (on charcoal kilns) under USAID's "Sudan Renewable
>Energy Project" in the mid-1980s, particularly studying "traditional"
>production techniques, which Ron Larson might be familiar with...

I was in Sudan only in 1982 and 1983 and never heard of this work.
Unfortunately, Sudan is essentially not on the Internet (I guess political
nervousness). Does anyone on the list have any continuing contacts
(especially e-mail) to either Sudan or to Derek Earle? GTZ was there
contemporaneously and might have some leads (and is on this list).

Incidentally, Sudan had (maybe still has) a quite remarkable
renewable energy program - many highly skilled and competent (and terribly
underpaid) researchers. It was recently chosen by all other African
countries to be one of only two renewable energy training countries.

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Mon Jul 7 23:24:34 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Heggie)
Message-ID: <v01540b01afe759dd67b0@[204.133.251.14]>

>Summary: Response to some of Andrew's comments today on charcoal-making
>stoves and kilns.

<snip>
RonL
>> 5. If flaring were perfected, we would probably see more use of the
>>flared gas valuable energy in places like bakeries, ceramics kilns,
>>brickmaking, etc.)

>(AJH) Yes this is what I most want to try, probably as an adjunct to
>woodburning in view of David Beedie's comments on the production curve of
>gases in a batch loaded gasifier.

(RWL): Today I received a copy of David's paper on his thesis and will try
to read it this PM. I believe the big difference is that David was
attempting to gasify the charcoal produced in the early part of his batch
operation. A charcoal-maker seems inherently simpler. (David - please note
arrival date - Thanks)

<skip>

(Ron):
>> If someone could test top-lit flaring with
>>a large metal charcoal kiln, I believe some major advances would result.
>
>(AJH) Greg is trying this, I am trying to persuade my co workers to load one
>kiln with uniform 2-10cms cordwood vertically stacked and top lit as per the
>stoves, attitudes are hard to change when production bonuses are at stake!
>
(RWL): Any potential sponsors out there who can solve this problem?

>
>
>(AJH) Agreed, without testing equipment I am not sure what part if any of
>the pyrolisis gases are oxidised in the kiln, I suspect your analysis is
>correct and hence the air used is primary, by your definition, and as no
>secondary air is available and the gases are in a moisture laden stream
>which inhibits combustion then they are vented with inevitable environmental
>consequences.

(RWL): I believe that virtually none "of the pyrolisis gases are oxidised
in the kiln" - if it is as tight as I gather it is. If top lit, I believe
all the gases that come off (not just the last gases) will be readily
combustible - just as in the charcoal-making stoves. There is no "warm-up"
period - unlike with bottom lighting.

(Andrew):
>I am still interested to hear what others think of the idea
>propounded by Tom Reed that bone dry wood might autopyrolise. This should
>have the benefit of evolving a gas of higher calorific value than the lean
>gas of a gasifier as no primary air would be needed and hence there would be
>no nitrogen to carry away sensible heat or dilute the calorific value.
>AJH

(RWL): If you place part of the fuel in an "almost-closed" can, then you
can achieve this higher calorific gas (reference a "Grover" design). Also,
there is some of this obtained in the higher pressure design of Mike Antal.
Feeding some of the energy back from the pyrolysis gases should also be a
way to increase the calorific value. But this requires fan power and a lot
more complexity that isn't going to fly in a lot of locations

But note what Elsen said in a message today - he had almost no
primary air entering his most recent stove at the lowest setting. It would
be interesting to determine the N2 percentage just before the secondary air
is encountered. .

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From english at adan.kingston.net Mon Jul 7 23:26:01 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:27 2004
Subject: More;Venturi Burner test
In-Reply-To: <14891.s335192@popserver.tue.nl>
Message-ID: <199707080317.XAA02157@adan.kingston.net>

> Alex English:
>
> > I did test the Pyromid with briquettes as fuel. CO was higher that
> > 2000ppm. CO2 at around 8%. The Pyromid has since left with the Burt's
> > on their vacation.
>
> Etienne:
> Your CO2 is too low. You should try to adjust your air supply to keep the O2
> roughly between 5 and 9 %, so your CO2 11-15%. In our downdraft these ranges
> give the lowest CO, obviously halfway the interval was best.

The Pyromid doesn't have an air supply control mechanism.

Also:Thanks for the review of your experimental methods. Our tools
impose limits on accurate interpretation that may out way protocol.
In spite of this I have learned more about CO in the last few days
than I would have predicted. Recent tests of the venturi burner have
shown me that when you combine the 'right' amount of air (as you
mentioned above) with concentrated mixing in an insulated chamber,
temperature soars and CO plummets.

Alex
>
> Etienne
> ---------------------------------------------
> Mr. Etienne Moerman E.Moerman@stud.tue.nl
> Joh. Buyslaan 71 tel. +31-40-2571491
> 5652 NJ EINDHOVEN The Netherlands
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Mon Jul 7 23:27:07 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:27 2004
Subject: Turbulent & diffusion blue flames
In-Reply-To: <9706078682.AA868293675@cc2smtp.nrcan.gc.ca>
Message-ID: <199707080317.XAA02153@adan.kingston.net>

Dear Skip

You wrote
spin>
> Modern, high static (eg Riello-type) flame retention head
> burners tend to hold the oil longer and have more intense mixing, so
> that this condition is not so pronounced.
AE: Our other boiler has a Riello Press 1 series burner as a
retrofit. I tested it today, 5ppm CO at 13%CO2. (CO/CO2 of .00004)
>
> With the blue flame burner, it is much more difficult to "tame" this
> initial unstable condition due to the lack of radiant heat in a
> transparent flame, etc.. One German blue flame burner (MAN) tried to
> get around this by running at fairly high excess air to start with,
> and then automatically closing down the air once equilibrium was
> established.
I don't understand how the high excess air increases heat.
While were on the blue theme:
I recently observed some propane burners on hot air balloons. They
have two modes of operation. One has preheated fuel which burns with
a noisy blue flame, the other bypasses the preheat and burns with a
quieter more luminous/yellow flame.(For night time display and not
scaring the cows.) Last year a boiler maker explained to me how with
two identical boilers, one fire with natural gas and the other with
oil, the one fired with oil would have a 3% high efficiency due to
higher heat losses from its radiant flame.

This probably isn't news to you but I though others might be
interested.

If your ever going down the 401, stop in, Burt's
greenhouses is just 2k north of the highway at Odessa.

Alex
>
> Hope this helps,
>
> Skip Hayden
> Senior Research Scientist
> Advanced Combustion Technologies
> ETB/CETC
> Ottawa, Canada K1A 1M1
>
> TEL: (613) 996-3186
> FAX: (613) 992-9335
> e-mail: skip.hayden@cc2smtp.nrcan.gc.ca
>
>
> ______________________________ Reply Separator _________________________________
> Subject: Re: Re[2]: Turbulent & diffusion blue flames
> Author: stoves@crest.org at internet
> Date: 7/7/97 7:54 AM
>
>
> Dear Skip
>
> Summary; Why?
> Skip wrote:
> > We developed a blue flame oil burner some years ago which
> > had a beautiful almost transparent flame, had very intense
> > swirl and low NOx. Its one drawback was that under
> > transient conditions, it was very susceptible to CO.
>
> What is meant by transient conditions? Was it more "susceptible" than
> the modern " flame retention" oil burners? If so, why?
>
> >
> > Hope this helps,
>
> Sharing your knowledge of combustion has been, and will be, very
> helpful.
>
> Alex
>
>
> > Skip Hayden
> > Senior Research Scientist
> > Advanced Combustion Technologies
> > Ottawa, Canada K1A 1M1
> > TEL: (613) 996-3186
> > FAX: (613) 992-9335
> > e-mail: skip.hayden@cc2smtp.nrcan.gc.ca
> >
> >
> >
> Alex English
> RR 2 Odessa Ontario
> Canada K0H 2H0
> 613-386-1927
> Stoves Web Site http://www1.kingston.net/~english/Stoves.html
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Mon Jul 7 23:27:09 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:27 2004
Subject: Top-lit designs (English request)
In-Reply-To: <v01540b00afe6bd61e7b0@[204.133.251.2]>
Message-ID: <199707080317.XAA02155@adan.kingston.net>

Summary: Alex responding to Ron.
> 4. Questions for Alex:
> a. Your use of a wire mesh at the bottom and sand for primary air supply
> control is the type of variation that we need to see more of. Did you feel
> it was satisfactory?
AE: No. No explaination yet.
> I have tried something similar with dirt used for
> controlling the secondary air supply (for snuffing) and a "pipe" to feed
> the primary air; I'm not very happy with that design. Elsen's use of
> concrete provides physical stability (while making a cheap air seal) - and
> is a direction I want to test next.
>
> b. In your 18 cm diameter design with 30 secondary air holes (6 mm
> dia), I would recommend a larger number of smaller holes - maybe even a
> slit. But I really haven't studied this enough. Before you scrap your
> first model, I hope you can add more secondary air holes in the 12 mm space
> between your existing secondary air holes.
AE: Ok.
>
> c. I would like to know the heights of your fuel/pyrolysis section and
> your combustion section.

AE: It is roughly one diameter to the bottom of the can of water.

> I think the height of the combustion section is
> most critical - needing to be at least as tall as the diameter - and
> perhaps even 50% larger. This needs a lot more study.
>
> d. You mentioned using "pipe". Was this ordinary stove pipe (which
> comes flat and can be quickly and easily "snapped" into a pipe shape)?
AE: It is slightly thicker.
>I think this may be a good design choice (being cheap and widely
>available in a wide range of diameters). I have used cans only
>because they are free
> and have a nice closed bottom. They are not tall enough and they are not
> very stable. Using Elsen's idea of concrete makes the stove pipe more
> attractive.
>
> e. You didn't mention wind screen - which is urgently needed for outdoor
> cooking.
AE: Wind was an issue. I had various poor solutions. I have the
option of eliminating the wind effect by conducting my tests in a
peak vented greenhouse.
> I am really intrigued by Elsen's use of
>perforated metal for the
> fuel container (as it apparently greatly improves the uniformity of
> charcoal production near the fuel container wall). There are a lot of
> ideas that can be tested with this. Perhaps the perforations can be
> extended all the way up through the combustion region - where the upper set
> of holes are perhaps used to hold insulation in place.
>
> f. I'd like to hear more about your fuel. I believe vertical round
> branches work a lot better than "square" samples, because the latter can
> mesh too closely together and prevent (or slow down) pyrolysis.

AE: I will start to use more round wood. I was trying not to change
to many variables at once, so I stuck with the dry cedar with my
other burner experiment.
>
> g. I'd like to hear a lot more from you and others about flame holding.
> I think there are many materials we can use that will help do better on
> this important aspect.
>
> h. I think there are some things you might suggest near the secondary
> air holes that would be like your Venturi designs - to improve mixing and
> turbulence (if those are helpful).

AE: Is it time for a hybrid. Throw away the falling cone and have
three air stages ? So many variations to try.

Sooner or latter Alex
>
>
> Good luck. Obviously, this type of stove will benefit from lots more
> imaginative development - and you have a big advantage in your CO/CO2
> measurement capabilities.
>
> Regards Ron
>
> Ronal W. Larson, PhD
> 21547 Mountsfield Dr.
> Golden, CO 80401, USA
> 303/526-9629; FAX same with warning
>
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From phait at transport.com Tue Jul 8 03:50:12 1997
From: phait at transport.com (John Doe)
Date: Tue Aug 31 21:35:27 2004
Subject: Charcoal lighting
Message-ID: <199707051536.IAA21378@butch.transport.com>

>Thomas B. Reed 303 278 0558 V Colorado School of Mines
>1810 Smith Rd., 303 278 0560 FX Department Chem Eng
>Golden, CO 80401 ReedTB@Compuserve.com
>ALSO: The Biomass Energy (non-profit)Foundation
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Dear Elsen et al:
>
>All this talk of charcoal brings up the subquestion of lighting.
>
>The Pyromid uses one small stick of lighter and is ready to cook in 6
>minutes. My two sons use large quantities of smoky lighter fluid and are
>ready to cook in 20 minutes. What do they do everywhere else? Is lighting
>a long process? Does it use a lot of "starter"?
>
>What about starting real charcoal vs starting briquettes?
>
>Just asking, TOM REED

>Dear Tom,

Thank you! The logical way to lite the fuel in a Pyromid is from bottom
up.Back up the igniter with a reflector,provide feeder air(holes in
liner),focus the energy towards the Black energy absorbing HTA(array of
briquettes or other fuels),and in a very short time you have the fuel
ignited. On the other hand, a pile of briquettes in a black energy absorbing
Weber pot has to be force ignited by dumping liquid fire-liter on the
briquettes.To some degree this is top down liting. When you want to make
Charcoal you Top Down Lite(TDL). When you want to ignite Charcoal you Bottom
up lite(BUL).

If you want to burn any natural fuel efficiently you organize it as best
possible in a Harmonic Thermal Array . Control the air to the array and trap
the gases coming off of the array long enough to get clean burning. The
plate that the gases go through or impinge upon in our cell gets red hot and
acts like a spark plug for the unburned (Pyrolisis?)gases. In our HTA cell
we use the heat coming off of both the top and bottom of the
cell(efficiency). This concept is now being commercially sold in our
Campmaster Duo and our Super Grill.

As we all suspected, as soon as the list started to get a balance of
marketing as well as R&D inputs, with a little bit of friendly competition,
there is a fresh and healthy dynamics that has started up that will bring
about solutions to this vexing Stove problem at a much earlier date. The
interchange has been fabulous and the players are some of the most
purposeful and principled people that I have ever encountered. We are all
dealing with a very practical World problem that has not had enough media
recognition. Nor, as can be seen in Mike Besses inputs, is it hard to see
how one can make a profit on stoves that cost one dollar.That is definitely
a low labor cost local product industry. However, Pyromids two for one
solution for the number one problem program allows us to get the Haves to
buy for the Have Nots and thus get an improved fuel burning principal into
the hands of both groups at a profit.Which unfortunately is essential if we
expect to survive.

The recent Alex CO test on the Pyromid with briquettes is very interesting
and clearly indicates that open burning briquettes, as opposed to closed
burning briquettes( HTA CELL), may be very different.I would need to know if
Alex had the array fully lit.Or was his measurement early in the lighting
cycle?We have found very clean burning when the array is at Super
Heat(1100F). It would be interesting to know what 80 briquettes burning in a
Weber generate in CO. If we can do the job with 9 to 25 briquettes then why not?

Our Super Heat Insert that goes into the Weber was designed to reduce the
consumption of Briquettes by 75% and totally eliminate the need for liquid
fire liter.Again,why not?The recent passing of the air pollution law
dictates more efficient use of Briquettes, and less of them. Also, I might
point out that the gas lovers of the World still don't have a safety answer
for six people in an apartment house elavator carrying propane bottles up to
their apartments for summer barbequing.I would much rather be in that
elevator with six bags of briquettes. Pressurized gas systems can be
dangerous if not properly handled.

There is still hope for efficient Charcoal Burning systems Worldwide.There
is still hope for efficient Wood Burning systems Worldwide. There is still
hope for efficient Tandom systems Worldwide. In short there is no one
answer, but a combination of answers that all utilize the best physics
principals of efficient fuel making and fuel burning. And to think I only
had a cup of coffee this morning. I have not got my computer sitting on a
soap box either, Alex.

Ronals comments that he makes Charcoal in the Charcoal Making Stove and then
I burn the Charcoal efficiently in our Cell is a good Tandom concept.That
Tandom Stove is what I believe is the final answer and we are pursuing that
approach right now.That is all I can say at this time.

Have a great 4th and watch the Mars pictures because they show what the
Earth could look like if we don't get a handle on this natural fuel burning
problem.
King Solomon must have moved to Mars after he ran out of fuel in the Middle
East.

Cheers!

Paul

From skip.hayden at cc2smtp.NRCan.gc.ca Tue Jul 8 08:51:54 1997
From: skip.hayden at cc2smtp.NRCan.gc.ca (Skip Hayden)
Date: Tue Aug 31 21:35:27 2004
Subject: Turbulent & diffusion blue flames
Message-ID: <9706088683.AA868377077@cc2smtp.nrcan.gc.ca>

Alex:

The reason that oil will (almost) always be higher in efficiency than
natural gas is not due to the radiant flame, but rather due to the
difference in what we call "Hydrogen Loss". With natural gas having
much more hydrogen than No.2 oil, the latent heat loss for the former
is much higher and is a fixed loss unless you condense the flue gases.
3% is actually a conservative number if you have a good oil burner.

The high excess air at the beginning was not to increase heat, but
rather to ensure better mixing between the fuel and air until the
conditions stabilized.

Skip Hayden

______________________________ Reply Separator _________________________________
Subject: Re: Re[4]: Turbulent & diffusion blue flames
Author: stoves@crest.org at internet
Date: 7/7/97 11:27 PM

Dear Skip

You wrote
spin>
> Modern, high static (eg Riello-type) flame retention head
> burners tend to hold the oil longer and have more intense mixing, so
> that this condition is not so pronounced.
AE: Our other boiler has a Riello Press 1 series burner as a
retrofit. I tested it today, 5ppm CO at 13%CO2. (CO/CO2 of .00004)
>
> With the blue flame burner, it is much more difficult to "tame" this
> initial unstable condition due to the lack of radiant heat in a
> transparent flame, etc.. One German blue flame burner (MAN) tried to
> get around this by running at fairly high excess air to start with,
> and then automatically closing down the air once equilibrium was
> established.
I don't understand how the high excess air increases heat.
While were on the blue theme:
I recently observed some propane burners on hot air balloons. They
have two modes of operation. One has preheated fuel which burns with
a noisy blue flame, the other bypasses the preheat and burns with a
quieter more luminous/yellow flame.(For night time display and not
scaring the cows.) Last year a boiler maker explained to me how with
two identical boilers, one fire with natural gas and the other with
oil, the one fired with oil would have a 3% high efficiency due to
higher heat losses from its radiant flame.

This probably isn't news to you but I though others might be
interested.

If your ever going down the 401, stop in, Burt's
greenhouses is just 2k north of the highway at Odessa.

Alex
>
> Hope this helps,
>
> Skip Hayden
> Senior Research Scientist
> Advanced Combustion Technologies
> ETB/CETC
> Ottawa, Canada K1A 1M1
>
> TEL: (613) 996-3186
> FAX: (613) 992-9335
> e-mail: skip.hayden@cc2smtp.nrcan.gc.ca
>
>
> ______________________________ Reply Separator
_________________________________
> Subject: Re: Re[2]: Turbulent & diffusion blue flames
> Author: stoves@crest.org at internet
> Date: 7/7/97 7:54 AM
>
>
> Dear Skip
>
> Summary; Why?
> Skip wrote:
> > We developed a blue flame oil burner some years ago which
> > had a beautiful almost transparent flame, had very intense
> > swirl and low NOx. Its one drawback was that under
> > transient conditions, it was very susceptible to CO.
>
> What is meant by transient conditions? Was it more "susceptible" than
> the modern " flame retention" oil burners? If so, why?
>
> >
> > Hope this helps,
>
> Sharing your knowledge of combustion has been, and will be, very
> helpful.
>
> Alex
>
>
> > Skip Hayden
> > Senior Research Scientist
> > Advanced Combustion Technologies
> > Ottawa, Canada K1A 1M1
> > TEL: (613) 996-3186
> > FAX: (613) 992-9335
> > e-mail: skip.hayden@cc2smtp.nrcan.gc.ca
> >
> >
> >
> Alex English
> RR 2 Odessa Ontario
> Canada K0H 2H0
> 613-386-1927
> Stoves Web Site http://www1.kingston.net/~english/Stoves.html
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Tue Jul 8 08:58:02 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:27 2004
Subject: Charcoal Lighting
Message-ID: <199707081258.IAA12728@adan.kingston.net>

Summary: No content.

Dear Paul
You wrote:
"There is still hope for efficient Charcoal Burning systems
Worldwide.There is still hope for efficient Wood Burning systems
Worldwide. There is still hope for efficient Tandom systems Worldwide.
In short there is no one answer, but a combination of answers that all
utilize the best physics principals of efficient fuel making and fuel
burning. And to think I only had a cup of coffee this morning. I have
not got my computer sitting on a soap box either, Alex."

AE: I have mine mounted on a podium. I sit on a pedestal. No
percolator though, Paul

Alexander the Great....Ape

Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From BeedieD at Cardiff.ac.uk Tue Jul 8 09:32:29 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Bess, Moerman, Hait)
Message-ID: <3613DCE4181@nrd1s.cf.ac.uk>

Summary: what is CV of early gases evolved from charcoal kiln ?

Andrew,
Regarding the following excerpt I've snipped from your recent
posting, can you suggest a figure for the CV of the gases evolved from
a charcoal kiln during the early (steaming) part of the cycle? [Net
CV (i.e. assuming combustion product moisture is in gaseous form) is
probably the most useful measure.]
?
DB.

> Date sent: Sat, 5 Jul 1997 12:09:08 +0100
> To: stoves@crest.org
> From: Andrew Heggie <ahe1@cableol.co.uk>
> Subject: Re: Stove Characteristics (Bess, Moerman, Hait)
> Send reply to: stoves@crest.org
...
> The necessity to maintain a hot chamber with preheating by propane into
> which steam and pyrolysis gases are blown and oxidised, as implemented by
> Greg Brown to comply with smoke regulations in Florida, is a short term
> solution (kludge?) to pollution where the luxury good ( barbecue charcoal)
> can stand the expense but long term the dual use such as Alex's and
> Etienne's desighns must be faourable?

*******************************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From E.Moerman at stud.tue.nl Tue Jul 8 10:55:23 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:27 2004
Subject: CO production (Larson)
Message-ID: <17736.s335192@popserver.tue.nl>

Etienne:
The most important cause here seems to be no or bad maintenance of the
burners. Of cause this is made more severe in well insulated spaces.

------

Ronal W. Larson writes:
> 4. Have you ever measured the CO emissions from charcoal-burning
> stoves - and can you guess as to why CO emissions are or could be higher
> from such stoves? (and how to minimize the emissions?)
>

Etienne:
I did do these measurements. My guess as to why emissions are high(er) is
that the charcoal combustion occurs at the surface of the charcoal to CO.
For this the diffusion process is very important. If diffusion is sufficient
some surface combustion can occur to CO2. A secondary reaction CO->CO2 in
the gas phase occurs in a small flame enveloping the piece of char. Again
diffusion is very important, insufficient diffusion means high CO levels.
The small flame is usually only a little larger than the piece of char on
which it 'feeds', this means a very little mixing length. Also I suspect
that the reaction temperature at the charcoal surface is substantially lower
than the reaction (adiabetic) flame temperature of the volatiles. Our
thermocouple measurements seem to indicate this. However I don't think
thermocouples are appropriate for the measurement of these reaction
temperatures.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From ahe1 at cableol.co.uk Tue Jul 8 13:03:09 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Heggie)
Message-ID: <9707081703.AA22287@mars.cableol.net>

At 21:26 07/07/97 -0600, you wrote:
Summary: Bioregional Charcoal Company will attempt top lighting of
vertically stacked small diameter cordwood

>(Ron):
>>> If someone could test top-lit flaring with
>>>a large metal charcoal kiln, I believe some major advances would result.
>>
>>(AJH) Greg is trying this, I am trying to persuade my co workers to load one
>>kiln with uniform 2-10cms cordwood vertically stacked and top lit as per the
>>stoves, attitudes are hard to change when production bonuses are at stake!
>>
> (RWL): Any potential sponsors out there who can solve this problem?

Well this e-mail has persuaded "the management" that we should make the effort.

After completion of the next burn we will set aside a 1.8m diameter 1.2m
high single tier kiln with a shallow conical roof. There is currently no
centre hole in the roof. Any suggestions appreciated. The assumed modus
operandi is we form the ventilation openings on the floor as at present.
Then 2-10cms diam cordwood will be placed vertically to fill the kiln. Fines
and brands (torreyfied wood?) will be placed on the top in the middle and
lit. First problem, shall we form a hole in the lid with two concentric
tubes (stove pipe) the outer open to atmosphere at the bottom to supply
preheated secondary air for the flaring or shall we allow gasses to escape
via a propped lid and flare the slit so formed? Currently we use 3 inlets
and 3 chimneys, shall we use all current openings as inlets only, this would
best seem to mimic the Larson-Reed stove. Air would rise through the inlets
to reach the burning coals and exit via the top to be flared with the
addition of secondary air. As burning starts the pyrolysis zone should move
down and encounter incoming air, this air should be depleted of oxygen at
the pyrolysis front, leaving charcoal formed earlier in a reducing
atmosphere above. If the pyrolysis zone moves down uniformly then as soon as
fire is visible in the inlet ports it should be possible to close the inlets
and continue flaring until gas is exhausted. Hence the conventional chimneys
should not be necessary?

If the burn completes, a big if as our wood will not be very dry, then we
shall do some weight measurements for yield.

AJH

From BeedieD at Cardiff.ac.uk Tue Jul 8 13:28:01 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Heggie)
Message-ID: <3652A3168BD@nrd1s.cf.ac.uk>

Summary: in batch-loaded gasifier, residual char
gasification/combustion helps to kickstart next fuel load.

Ron,

> >(AJH) Yes this is what I most want to try, probably as an adjunct to
> >woodburning in view of David Beedie's comments on the production curve of
> >gases in a batch loaded gasifier.
>
> (RWL): Today I received a copy of David's paper on his thesis and will try
> to read it this PM. I believe the big difference is that David was
> attempting to gasify the charcoal produced in the early part of his batch
> operation. A charcoal-maker seems inherently simpler. (David - please note
> arrival date - Thanks) OK. Transit time ~1 week.

The big 'stove' I worked on was best operated for several fuel-loads
continuously, the hot char and high structure temperatures remaining
from one load helping to 'kick-start' the next load. The char bed
depth remaining at the optimum reload time stabilised after 2-3 loads.

Dave.
*******************************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From ahe1 at cableol.co.uk Tue Jul 8 15:43:30 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:27 2004
Subject: Stove Characteristics (Bess, Moerman, Hait)
Message-ID: <9707081943.AA26359@mars.cableol.net>

Summary: what is CV of early gases evolved from charcoal kiln ?
David
At 14:31 08/07/97 GMT, you wrote:
>
>Andrew,
>Regarding the following excerpt I've snipped from your recent
>posting, can you suggest a figure for the CV of the gases evolved from
>a charcoal kiln during the early (steaming) part of the cycle? [Net
>CV (i.e. assuming combustion product moisture is in gaseous form) is
>probably the most useful measure.]
>?
I have not any way of measuring this, actually (as you infer)as it contains
visible water vapour there would be some energy consumed in turning these
droplets to steam at approximately 2.7-2.9 mJ/kg depending on the flue
temperature. At this stage wood is being burned to drive off moisture in the
charge, that is why Ronal suggested it is highly polluting as its CV is not
high enough to sustain flaring because of dilution of any pyrolysis gasses
by combustion products, steam amd free water droplets. This is why I
suggested using bone dry wood, obviously not practical in the field and then
we could calculate input CV of wood at 18.6 mJ/kg less output CV of charcoal
at 30mJ/kg the differences would be in 1)heat loss from system, 2)sensible
heat of charcoal 3)sensible heat of gasses 4)CV of gases. For instance if
1kg of wood reduced to .25kg of charcoal then energy difference is 11.1mJ.
If the kiln temperature was 300c then we would know .75kg of gases and .25kg
of charcoal at 300C at their respective specific heats were accounted for.
The balance should be in the losses from the vessel ( I wish to move away
from kilns, too much black art involved), which could be minimised with
insulation, and chemical energy of the gases, or am I being too simplistic.
Not everyday calculations for a woodman!
AJH

From english at adan.kingston.net Tue Jul 8 22:42:14 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:27 2004
Subject: New pictures of AE's VB
Message-ID: <199707090242.WAA09322@adan.kingston.net>

Dear Stovers,

I just put some recent pictures of my burner on the Web. They include
some flame shots.

Alex
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Tue Jul 8 23:21:49 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:27 2004
Subject: Turbulent & diffusion blue flames
In-Reply-To: <9706088683.AA868377077@cc2smtp.nrcan.gc.ca>
Message-ID: <199707090322.XAA10644@adan.kingston.net>

Dear Skip +
> Alex:
>
> The reason that oil will (almost) always be higher in efficiency than
> natural gas is not due to the radiant flame, but rather due to the
> difference in what we call "Hydrogen Loss".
snip

Thanks for straightening that out.

So is there any difference in the furnace exit gas temperature (ex.
gas temperature entering fire tubes in a scotch boiler) due to the
different radiant flame characteristics?

I would like to tie this back to the small stove
experiments. The regular carbon steel stove pipe that the combustion
chamber/ chimney above the venturi is made of, is flaking ( what is
this flaking process called) due to the high heat and shows that it
is not an adequate material for the job. How much would stainless
steel add to the combustion dynamic due to its reflectivity? This
must tie back to the flame emmisivity and absorbtivty, and perhaps
its colour. My gut feeling is that this is all of secondary
I'mportants compared to that of material durability.

During my experiments I have noticed a consistent tendency for the
flame to contain more blue as the burn progresses. I'm inclined to
think it is due to a gradual change in the constituents of the
pyrolisis products. Is there a simple explaination keeping in mind
this is a top lit stove.

Alex

> With natural gas having
> much more hydrogen than No.2 oil, the latent heat loss for the former
> is much higher and is a fixed loss unless you condense the flue gases.
> 3% is actually a conservative number if you have a good oil burner.
>
> The high excess air at the beginning was not to increase heat, but
> rather to ensure better mixing between the fuel and air until the
> conditions stabilized.
>
> Skip Hayden
>
>
> ______________________________ Reply Separator _________________________________
> Subject: Re: Re[4]: Turbulent & diffusion blue flames
> Author: stoves@crest.org at internet
> Date: 7/7/97 11:27 PM
>
>
> Dear Skip
>
> You wrote
> spin>
> > Modern, high static (eg Riello-type) flame retention head
> > burners tend to hold the oil longer and have more intense mixing, so
> > that this condition is not so pronounced.
> AE: Our other boiler has a Riello Press 1 series burner as a
> retrofit. I tested it today, 5ppm CO at 13%CO2. (CO/CO2 of .00004)
> >
> > With the blue flame burner, it is much more difficult to "tame" this
> > initial unstable condition due to the lack of radiant heat in a
> > transparent flame, etc.. One German blue flame burner (MAN) tried to
> > get around this by running at fairly high excess air to start with,
> > and then automatically closing down the air once equilibrium was
> > established.
> I don't understand how the high excess air increases heat.
> While were on the blue theme:
> I recently observed some propane burners on hot air balloons. They
> have two modes of operation. One has preheated fuel which burns with
> a noisy blue flame, the other bypasses the preheat and burns with a
> quieter more luminous/yellow flame.(For night time display and not
> scaring the cows.) Last year a boiler maker explained to me how with
> two identical boilers, one fire with natural gas and the other with
> oil, the one fired with oil would have a 3% high efficiency due to
> higher heat losses from its radiant flame.
>
> This probably isn't news to you but I though others might be
> interested.
>
> If your ever going down the 401, stop in, Burt's
> greenhouses is just 2k north of the highway at Odessa.
>
> Alex
> >
> > Hope this helps,
> >
> > Skip Hayden
> > Senior Research Scientist
> > Advanced Combustion Technologies
> > ETB/CETC
> > Ottawa, Canada K1A 1M1
> >
> > TEL: (613) 996-3186
> > FAX: (613) 992-9335
> > e-mail: skip.hayden@cc2smtp.nrcan.gc.ca
> >
> >
> > ______________________________ Reply Separator
> _________________________________
> > Subject: Re: Re[2]: Turbulent & diffusion blue flames
> > Author: stoves@crest.org at internet
> > Date: 7/7/97 7:54 AM
> >
> >
> > Dear Skip
> >
> > Summary; Why?
> > Skip wrote:
> > > We developed a blue flame oil burner some years ago which
> > > had a beautiful almost transparent flame, had very intense
> > > swirl and low NOx. Its one drawback was that under
> > > transient conditions, it was very susceptible to CO.
> >
> > What is meant by transient conditions? Was it more "susceptible" than
> > the modern " flame retention" oil burners? If so, why?
> >
> > >
> > > Hope this helps,
> >
> > Sharing your knowledge of combustion has been, and will be, very
> > helpful.
> >
> > Alex
> >
> >
> > > Skip Hayden
> > > Senior Research Scientist
> > > Advanced Combustion Technologies
> > > Ottawa, Canada K1A 1M1
> > > TEL: (613) 996-3186
> > > FAX: (613) 992-9335
> > > e-mail: skip.hayden@cc2smtp.nrcan.gc.ca
> > >
> > >
> > >
> > Alex English
> > RR 2 Odessa Ontario
> > Canada K0H 2H0
> > 613-386-1927
> > Stoves Web Site http://www1.kingston.net/~english/Stoves.html
> >
> >
> >
> Alex English
> RR 2 Odessa Ontario
> Canada K0H 2H0
> 613-386-1927
> Stoves Web Site http://www1.kingston.net/~english/Stoves.html
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Wed Jul 9 09:34:44 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:28 2004
Subject: Top lit gasifier trial 2
Message-ID: <199707091335.JAA22093@adan.kingston.net>

Summary: Top lit gasifier trial produces a stable visually smokeless
burn.
Dear Ron, Elsen +
I did as Ron suggested and drilled holes (4mm) inbetween all the 6mm
holes. The pipe is still sitting on a wire mesh with sand as a "below
fuel air regulator. Flame attachment to the over fire air holes was
variable. The flame often danced at a point closer to the centre. There was often
plenty of blue in the flames. The flame gathers in the centre with
too much dead space around it. With no insulation and to
much excess air, with CO2 at 8% (CO fluctuated over and just under
the instruments limit of 2000ppm), these readings are not surprising.
This is likely due to the excessive space, chimney, around the can
of water. The same space which allows me to watch.

We are all dancing around the tree of 'temperature' and
'turbulence', I hope were having a good 'time'. Alex
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From jflores at prolena.sdnhon.org.hn Wed Jul 9 10:44:25 1997
From: jflores at prolena.sdnhon.org.hn (jflores@prolena.sdnhon.org.hn)
Date: Tue Aug 31 21:35:28 2004
Subject: Stove price
Message-ID: <199707091238.IAA25027@sdnhon.org.hn>

!!Fecha envio: Mon, 7 Jul 1997 16:50:18 +0100
!!A: stoves@crest.org
!!De: Mike Bess <mike@esd.co.uk>
!!Asunto: Re: Stove price
!!Enviar resp a: stoves@crest.org

!!Dear Juan Carlos,
!!
!!I apologise for the delay in responding to your e-mail. Let me clarify
!!that I have been speaking of two types of stoves in Ethiopia; the first
!!is called the "Lakech" (can mean "splendid", "beautiful"), and the
!!"Mirte" (which can mean "better"). The lakech is an improved charcoal
!!stove that incorporates a ceramic liner set into a thin metal housing.
!!The Lakech has sold 300,000 stoves over the past five years while the
!!Mirte is entering its third year of commercial sales and has sold over
!!17,000 stoves.
!!
!!The Mirte may be of more interest to you than the Lakech. It is
!!designed to burn wood, branches, leaves, sawdust and most other biomass
!!(it does not burn dung efficiently). It is made from a mixture of
!!cement and various other building materials (pumice, scoria, sand,
!!etc.). It is made in six pieces using two moulds. It retails at about
!!3.5 or US$ 5.00 to 5.50 in most areas.

JCF> This price is cheper than our price. Now, we sell each
stove for US$ 30, in the price we put the traing of the buyer, the
warranty, some material (paper, brochures), the pay of the person who
build the stove. In material we spent about U$S 25. The cost of the
chimenea and the plancha is US$ 20.

Do you put the training cost in this price or only the cost of the
materials?

!!The Mirte incorporates a "mtad" which is a traditional ceramic
plate
!!that is used to bake "injera", the traditional Ethiopian flat bread. It
!!has certain similarities to tortillas, to Indian chapatis, except it is
!!made from a pancake like batter, which is poured on the plate and
!!cooked. The typical housewife cooks 30 injeras in one session, and must
!!cook twice a week.

JCF> This is good, maybe we could try to sell this stove here,
in Honduras and Nicaragua.

!!One of the fascinating things about the Mirte and its commercialisation
!!is that it is very popular with commercial injera bakers. There are
!!several photos now up on the "stovers" Web site, which could give you
!!more of a pictorial view. The commercial bakers sell injera to other
!!households, to restaurants, hotels, bars, etc. Some commercial bakers
!!bake over 300 injera a day per stove, working for over 15 hours, often
!!employing several other women, to bake over 1,000 injeras per day.
!!
!!The Mirte reduces wood consumption by about half in actual household
!!practice, and even more in commercial cooking circumstances. It reduces
!!smoke considerably, which is why most cooks prefer it. It also protects
!!them from the flames. It is clean. These are all features which make
!!it popular.

JCF> The reduce that you said, it's a result of a study,
or a result of the people report as reduce. In our case we have a
reduction of 25% in the comsumption, but when we ask to the people
they said that they have a reduction more than 50%. We know. Thsi is
because people are very happy with the stove, and they think that
they have to said that in order to keep we happy with them, but the
real reduction is only 25% and no 50% how they said. We know that
plancha stove can reduction more the comsumption, but we have to work
ib training the people in use the stove.

!!
!!I hope this answers some of your questions. All the best, Mike Bess,
!!mike@esd.co.uk
!!--
!!Mike Bess
!!----------------------------------------------------------------------
Juan Carlos Flores Lopez
Director Ejecutivo PROLENA/Honduras
Tel/Fax: (504) 32-0639
P.O.Box 3870 Tegucigalpa, Honduras.
E-Mail: jflores@prolena.sdnhon.org.hn
----------------------------------------------------------------------

From jflores at prolena.sdnhon.org.hn Wed Jul 9 10:44:29 1997
From: jflores at prolena.sdnhon.org.hn (jflores@prolena.sdnhon.org.hn)
Date: Tue Aug 31 21:35:28 2004
Subject: Plancha Stove
Message-ID: <199707091238.IAA25028@sdnhon.org.hn>

!!Fecha envio: Mon, 7 Jul 1997 17:18:57 +0100
!!A: stoves@crest.org
!!De: Mike Bess <mike@esd.co.uk>
!!Asunto: Re: Plancha Stove (J. Flores)
!!Enviar resp a: stoves@crest.org

!!Dear Juan Carlos,
!!
!!I apologise for coming into the group late, and not being familiar with
!!all that has been said before. I am interested in your plancha stove
!!because it has many similarities to other high mass stoves that try to
!!address the issues of improved wood burning. You wrote:
!!
!!>JCF> The consumption with the plancha stove is about 20%
!!>less than in the non-improved woodstove, and the consuption per day
!!>is 65.64 Kg. The people use the woodstove about 10-12 hors per day,
!!>the time use depend in the work of the people. For exempla if the
!!>person make "tortillas" (a kind of food that is made of corn) they
!!>use the woodtove about 12 hours per day. The rates of consumption are
!!>from 93 Kg/week to 39.5 Kg/week. The different is big because there
!!>aren't a stadistic control, so in some cause the woman cook for more
!!>than 6 person and she has to make torillas. The women that make
!!>tortillas make more than 1200 tortillas per day, and they have to
!!>cook all the day. In another case the people don't have the enough
!!>education for using the woodstove, and they don't use the woodstove
!!>in the right way. This is a very important point, because if we want
!!>the people use the improved woodstove, we have to training them, and
!!>to explain them Why they have to use the new woodstove.
!!
!!My question is "how do you guarantee quality control of the plancha
!!stove to maintain efficiencies, and how do you commercialise of
!!disseminate it to a wide audience"? The reason I ask, is that our
!!experience is that without standardisation of high mass stoves, which is
!!always a problems with self-made stoves, quality, consequently
!!efficiency, varies dramatically. Also, self-made stoves are not
!!interesting to most urban women who prefer to pay for their fuel and the
!!stoves that burns the fuel. But, even if you can manage to work
!!intensively with women who make the stove, how do you expand production
!!and dissemination to tens of thousands of households and cooks and still
!!maintain quality and efficiency?
!!
!!I ask these questions because we faced the same problems and we found
!!that we had to standardise the stove in order to reach larger numbers
!!and to keep efficiencies high. This requires some form of mass
!!production. As Etienne and others have noted, simply enclosing an open
!!fire can easily dramaticallay improve efficiencies; so does good
!!practice and husbandry. But, we know that not everyone is a good cook,
!!and not everyone will mind a stove in the best way. So, to remove this
!!people variation factor, we believe there must be standardisation that
!!allows for very little variation in actual use. I would be interested
!!to learn of your experiences.

JCF> We know that this is a hard work, so we have to control
the quality because we are starting to become commercial the
woodstove. Before we star the project, in Honduras the woodstove
project only build the woodstove and then they leave the person, so
in this case the person doesn't have enough knowledge in how they
have to use the stove.

We star training our builder or stove-maker. We give them a good
training, and we select only the most interested people, and the best
of the group. We pay them for each stove that they build, and we have
a control of the stove that they built. We make a list of the house
that want to have a stove, so we know who make the stove. Then, the
person who buy the stove have our tel. number, so they can call us if
they have a problem with the stove. When we received the tel. call,
we spend a person to look for the problem. If the problem is a result
of the builder, we call her, so we tell her the problem, if she want
to be in our group, she has to be responsible for the problem, and
she has to fix it. In order to have a good group of builder, we pay
them US$ 4 per each stove that they make, and this is a good salary
here in Honduras, because they can build 4 or more stove in a day, so
in a month she get US$ 400. The warranty that we give is for 6 month,
because this is a enough time to see the stove that were built in bad
way. This is about the human error, but we have a warranty in the
chimenea and the plancha, in this case we sign a contract with the
person who make it, so if the chimenea or the plancha have a problem,
the person have to replace it. We put in the price a rate of 10% for
warranty, if the person doesn't want to pay it, we don't give them
they warranty.
----------------------------------------------------------------------
Juan Carlos Flores Lopez
Director Ejecutivo PROLENA/Honduras
Tel/Fax: (504) 32-0639
P.O.Box 3870 Tegucigalpa, Honduras.
E-Mail: jflores@prolena.sdnhon.org.hn
----------------------------------------------------------------------

From mike at esd.co.uk Wed Jul 9 13:11:38 1997
From: mike at esd.co.uk (Mike Bess)
Date: Tue Aug 31 21:35:28 2004
Subject: Stove price
In-Reply-To: <199707091238.IAA25027@sdnhon.org.hn>
Message-ID: <KQpTWBA3D8wzUAFY@esd.co.uk>

In response to Juan Carlos' requests:

>JCF> This price is cheper than our price. Now, we sell each
>stove for US$ 30, in the price we put the traing of the buyer, the
>warranty, some material (paper, brochures), the pay of the person who
>build the stove. In material we spent about U$S 25. The cost of the
>chimenea and the plancha is US$ 20.
>
>Do you put the training cost in this price or only the cost of the
>materials?

We train up producers, but we do not charge them a training fee. The
artisans/producers install the Mirte, and give some instructions to the
cook on how to maintain it. But, because it is all pre-fabricated,
there is really no training required for the cook. So, there is no
training cost as there would be if the stove were produced or installed
by the cook.
>
>!!The Mirte incorporates a "mtad" which is a traditional ceramic
>plate
>!!that is used to bake "injera", the traditional Ethiopian flat bread. It
>!!has certain similarities to tortillas, to Indian chapatis, except it is
>!!made from a pancake like batter, which is poured on the plate and
>!!cooked. The typical housewife cooks 30 injeras in one session, and must
>!!cook twice a week.
>
>JCF> This is good, maybe we could try to sell this stove here,
>in Honduras and Nicaragua.
>
We could send you the specifications for making the moulds, the
dimensions, and the mix, but I believe you will have to adapt it to your
own conditions in Honduras and Nicaragua. The plate or "mtad" is
between 54 to 60 cm in diameter. This is because "injera"( Ethiopian
bread) is large. It is later cut before being served. I believe your
tortillas are much smaller in size, so that you would not want or need
such a large plate (I believe you can see the Mirte on the stovers Web
page to give you a better idea). I don't know what down sizing the
dimensions will do to efficiencies, but it is something you might wish
to try.

>!!The Mirte reduces wood consumption by about half in actual household
>!!practice, and even more in commercial cooking circumstances. It reduces
>!!smoke considerably, which is why most cooks prefer it. It also protects
>!!them from the flames. It is clean. These are all features which make
>!!it popular.
>
>JCF> The reduce that you said, it's a result of a study,
>or a result of the people report as reduce. In our case we have a
>reduction of 25% in the comsumption, but when we ask to the people
>they said that they have a reduction more than 50%. We know. Thsi is
>because people are very happy with the stove, and they think that
>they have to said that in order to keep we happy with them, but the
>real reduction is only 25% and no 50% how they said. We know that
>plancha stove can reduction more the comsumption, but we have to work
>ib training the people in use the stove.

The reduction is in actual tests. We tested the Mirte extensively (and
continue to do so) in the laboratory using controlled cooking tests.
They show a consistent 40-45% reduction in wood consumption for baking
injera. We have carried out a total of five kitchen performance tests
each with 40 households (each with test groups of 30 and control groups
of 10) and each over a ten week period, testing consumption prior to
installation of the stove, and after the installation. The test groups
provided the background to see what changes in performance might be due
to external factors such as price changes, weather, etc.

These kitchen performance tests consistently and statistically showed
the Mirte reducing wood consumption by over 40%, and very close to 50%.
Net consumption drops even further with commercial bakers as they are
using the stove all the time, and there are few efficiency losses due to
start and stop baking (and commercial bakers are generally so much more
efficient bakers than households).

I hope these answer some of your questions. All the best! Mike
--
Mike Bess

From gayathri at aero.iisc.ernet.in Wed Jul 9 13:47:55 1997
From: gayathri at aero.iisc.ernet.in (Gayathri)
Date: Tue Aug 31 21:35:28 2004
Subject: Stove Characteristics (Bess, Moerman, Hait)
Message-ID: <9707091758.AA26013@aero.iisc.ernet.in>

sorry

From butria at worldbank.org Wed Jul 9 16:09:56 1997
From: butria at worldbank.org (Boris Utria)
Date: Tue Aug 31 21:35:28 2004
Subject: Stove price
In-Reply-To: <KQpTWBA3D8wzUAFY@esd.co.uk>
Message-ID: <"E285ZWXRN2IAP*/R=WBWASH/R=A1/U=BORIS UTRIA/"@MHS>

TO: Managers of the Stove-Owner Network

From: Boris Utria, World Bank, Washington, DC

This is to let you know that due to a change in responsibilities
I will no longer be doing work on improved stoves. Because of that I
would appreciate if you could delete my mane from your automatic
mailing lists effectively immediately.

Thanks and best regards,

Boris Utria

From larcon at sni.net Wed Jul 9 17:31:26 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:28 2004
Subject: Top-lit charcoal kiln (Heggie)
Message-ID: <v01540b00afe97811f71f@[204.133.251.15]>

Summary: Some comments on Andrew's proposed testing of a top-lit large
charcoal kiln.

On July 8, Andrew said (about trying to top-light a large charcoal kiln):

>Well this e-mail has persuaded "the management" that we should make the effort.
>
>After completion of the next burn we will set aside a 1.8m diameter 1.2m
>high single tier kiln with a shallow conical roof. There is currently no
>centre hole in the roof. Any suggestions appreciated.

(RWL): Andrew - I think this is great news; thanks for going out on a limb.
I hope you realize that the following comments are not at all from
experience or knowledge of your operation - only an extension of working at
the 1/2 meter scale (with a total pyrolyzing time then of about 2 hours.
Your's should take at least 4-5 hours. What is your present firing time
for this size kiln?

1. Could you describe the height or pitch of this conical roof?

2. What diameter and length are the existing outer stove pipe pieces?

Unless there is a good reason not to, they probably are the right
pieces for the chimney, since they are otherwise not going to be used. (But
see below on using insulated (concentric) stove pipe.)

>AJH:
>The assumed modus
>operandi is we form the ventilation openings on the floor as at present.

(RWL): Maybe the more the better (at least at first) - since you will have
three extra (formerly) chimney openings that can be used.

>AJH
>Then 2-10cms diam cordwood will be placed vertically to fill the kiln. Fines
>and brands (torreyfied wood?) will be placed on the top in the middle and
>lit.

(RWL): With stacking as tightly as possible- maybe put the 10 cm pieces in
first and then later stuff the 2's in between. Straw or paper or almost
anything to help start the brands - maybe dropped down through the chimney.
I think the fines could cause a problem if they fall lit to the bottom. I
think the brands and lighting should be over the whole upper surface - not
just in the middle.

Maybe lighting can be from the edge at the same time - maybe using
a propane torch. If the wind blows out the flame you want to be able to
quickly relight the pyrolysis gases (which will be instantaneous).

During initial ignition, the bottom vents should all be open -
later they should be closed back to the point you feel comfortable with the
flame size.

>AJH:
First problem, shall we form a hole in the lid with two concentric
>tubes (stove pipe) the outer open to atmosphere at the bottom to supply
>preheated secondary air for the flaring or shall we allow gasses to escape
>via a propped lid and flare the slit so formed?

(RWL): 1. The two concentric tube design may be overkill at first. I
think this stove pipe will get orange-to-yellow hot and ordinary stove pipe
may not handle that temperature. You may want only one layer to cool it
down.

2. But the idea of pre-heating may be a good one - if I understand your
suggestion. I would hope that all combustion is complete inside the
chimney, but with too short a chimney this will not happen - and then
preheating more "tertiary" air might help.

3. My guess is that you will eventually settle on a chimney of between 1-2
meter height. The right height will give the proper draw of secondary air,
with the bottom air ports controlling the primary air (which controls the
intensity of the chimney flame. It would be good in the first experiment to
try several stove pipe heights to see which works best - but exchanging or
lengthening the chimney during operation may be pretty hazardous. True?
(The draft you get with a 1-2 meter chimney filled with burning gases will
be much more than in your present approach, so you may have difficulty
keeping the primary air low enough.)

4. You say "...or shall we allow gasses to escape via a propped lid and
flare the slit so formed?" I don't believe you will find sufficient draft
this way and the flame will be unstable with a wind. I think you must have
a slit and the secondary air flow will all be inward - hopefully with flame
holding right at the lip. Because of the draft from the 1-2 meter chimney,
all of the pyrolysis gases are swept inward and up. There should be no gas
leakage outward.

The width of this gap and how to vary it (and eventually close it)
will require some experimentation. I suppose a crowbar will work, with
wedges . I think 1-4 cm should be the range you need to try (maybe start
at 2). Maybe you could start with one side at 1 cm and the opposite side
at 3 or 4. Looking for good flame holding would seem to be the criteria
for appropriate gap size.

I would try to put some of the fuel (but not much) "blocking" the
secondary air slit a little bit as a means of flame holding.

>AJH
> Currently we use 3 inlets
>and 3 chimneys, shall we use all current openings as inlets only, this would
>best seem to mimic the Larson-Reed stove.

(RWL): As above - yes to using all six. Also maybe use rocks or crumpled
chicken wire (as a "grate") to be sure that primary air can get easily to
the center.

AJH:
>Air would rise through the inlets
>to reach the burning coals and exit via the top to be flared with the
>addition of secondary air.

(RWL): Rephrased: " Air would enter through the six inlets and, after
traveling horizontally at first, will rise through the vertically stacked
wood to the downward-moving pyrolysis zone. There it creates moderately
hot pyrolysis gases (some of which travel through the wood) which are
flared near the secondary air inlet with the addition of inward traveling
secondary air."

AJH:
> As burning starts the pyrolysis zone should move
>down and encounter incoming air, this air should be depleted of oxygen at
>the pyrolysis front, leaving charcoal formed earlier in a reducing
>atmosphere above.

(RWL): 1. First being a little picky here with the word "burning". I
presume this refers to the diffusion flame in the cone region where the
right ratio of pyrolysis gas and oxygen are in contact. At some later
stage - where you might be trying to transfer this pyrolysis gas to a
bakery or brick kiln for ignition there, a blower would replace the natural
draft.
2. The last phrase: " leaving charcoal formed earlier in a reducing
atmosphere above" doesn't sound quite right. I'd say either: "leaving
charcoal" or "with the resulting pyrolysis gases traveling upward past
charcoal formed earlier".
3. Part of the issue here is how long it takes to form charcoal
all the way to the inside of a thick piece. This is done partly via
conduction of heat inward, with some of the gases coming out radially, but
most gas (I think) coming out upward vertically through the already
produced charcoal. I think little of this interior (to a wood piece)
charcoal production uses much of the incoming oxygen. There will be some
splitting of the wood caused by expansion of interior trapped moisture and
this will help move heat inward also through hot gas contact. That portion
of the process which is exothermic of course helps further heat other
interior parts of the wood block.

AJH:
> If the pyrolysis zone moves down uniformly then as soon as
>fire is visible in the inlet ports it should be possible to close the inlets
>and continue flaring until gas is exhausted.

(RWL): The flame characteristic will change pretty rapidly at the end,
with a need to add extra primary air to keep the same type of flame.
Because you are flaring all gases (with hopefully no smoke), you will not
be able to tell from the usual change of smoke color - but I think the end
will be pretty clear. If you see flame at only one of the bottom inlet
ports, you probably should close off only that one. Feeling with your hand
(carefully) along the kiln skin every half-hour or so, should give a good
indication of when the conversion should be complete. Once you have the
flame size you want, you sholdn't need to adjust the primary air supply at
all. If the pyrolysis zone on one side seems to be moving more slowly than
other sides, the nearest primary air port should be opened a bit more.

The difference in time between finally closing the input ports and
the flame extinguishing will be measured in seconds.

AJH: > Hence the conventional chimneys should not be necessary?

RWL): Right.

>AJH:
>If the burn completes, a big if as our wood will not be very dry, then we
>shall do some weight measurements for yield.
>
>AJH

(RWL): If you can get a "fire" started, it should go to completion. I
hope you can get the wood as dry as possible. Can you estimate anything
now about the likely moisture content? If the wood looks or feels wet, I
wouldn't try it. But trying one section with some wet wood would be an OK
experiment.

I believe a big issue will be protecting against wind. Assuming
that you crack open the conical top for the secondary air, I think you
could lean pieces of sheet metal up against the top . Being flat, I think
you should be able to get plenty of secondary air in. Alternatively, maybe
you can hang something off of the conical top or off of the gap lip as a
wind shiled.

I also would worry about sealing the top-to-side joint when
pyrolysis is finished. Maybe some wet clay will help. I am assuming you
will have no trouble closig the primary air inlets.

You must be able to put a "pot" or something over the chimney of
course. I have successfully used a wet rag over the hole before placing
the upside-down "pot". If you get lots of smoke exiting through the
secondary air slit, you may have to open up and spray water inside. Maybe
using sand also. But maybe the smoking will stop if you have only
successfully closed all the lower air ports.

I hope others like Tom, Elsen, and Alex can correct or add to these
comments. The things I would worry about most are getting a good draft
(enough height) and finding ways to be flexible in the chimney height and
width of the secondary air slit.

Best of luck -

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From lunds at hnet.net Wed Jul 9 17:38:32 1997
From: lunds at hnet.net (The Lunds)
Date: Tue Aug 31 21:35:28 2004
Subject: NAME CONTEST
In-Reply-To: <199706290520_MC2-196C-BC15@compuserve.com>
Message-ID: <33C41FB5.7553@hnet.net>

Tom Reed wrote:
>
> TOM REED, CSM, reedtb@compuserve.com
> ELK et al:
>
> Sounds like you are making great quantitative progress with what you call
> the "two can stove". Congratulations - push on! Here are a few comments
> for your consideration.
>
> You asked what happens to the charcoal if it is not extinguished when the
> volatiles have all been consumed. If you put a thermocouple in the middle
> of the charge it will show you
>
> a) initially room temperature air passing by on the way up to the "flaming
> pyrolysis" zone (yes, there is a flame buried in the pile - we built a
> "transparent gasifier" with gold reflective insulation and could observe
> it)
>
> b) a very rapid rise in temperature to about 500 C as the flame approaches
> the thermocouple
>
> c) very little drop in temperature as the volatile flame approaches the
> bottom grate
>
> d) an immediate sharp rise in temperature as charcoal begins to burn
>
> So, one TC (or dial gauge thermometer) reveals the history quite
> accurately. I recommend that we all use such a buried TC for our tests
>
> ~~~~
> NAME OF STOVE CONTEST:
>
> NAME OF STOVE:
>
> It has been most amusing to follow the changing names given this stove. I
> initially (in 1985, patent memos to SERI/NREL) called it an
> "UPSIDEDOWNDRAFT GASIFIER" stove by analogy to the conventional "downdraft"
> gasifier, well known during WWII and also to emphasize that it cooked with
> GAS. After a year or two I realized the "upsidedowndraft", while colorful,
> was not informative to non-English speaking people (like Harry LaFontaine).
> So I changed to calling it the "Inverted downdraft gasifier-stove". When
> Fred Hottenroth produced a commercial model he called it a GASFIRE stove
> (1989). I have also called it a WOOD-GAS stove, with strong emphasis on
> GAS to avoid confusion with a few thousand wood stoves built through the
> ages. Gasifier stoves are NEW (and include the "J" stove of
> Verhart-Eindhoven-Antal).
>
> When Ron Larson called me to ask about charcoal making stoves he renamed it
> "a CHARCOAL MAKING" stove (1992). Others call it the TOP LIGHTED stove.
> Now you call it the TWO CAN" stove.
>
> It seems to me we have here the "blind men and the elephant" syndrome.
> Each person sees what he/she thinks is important. Coming from gasifiers
> and having used gas stoves, I think WOOD-GAS STOVE (as opposed to WOOD
> STOVE) is most descriptive and exciting. Ron comes from Ethiopia where the
> possibility of producing charcoal (always a nuisance in my eyes) was the
> most important feature.
>
> Now you use TWO CAN STOVE to describe it. Does the fact that it can (but
> not necessarily is) be made from two tin cans best catch the essense?
>
> I suggest we all submit our best choices for a single name to catch the
> essense. Ron can collect the names and we can all vote. Majority wins and
> we all sink or swim with the result.
>
> ~~~~~
> Fussing over names may seem nit-picking. Nonsense. A good name is almost
> as important as a good product.
>
> OIL SHALE is not truly a shale, nor does it contain oil. It is keragenated
> marlstone. How much funding would Congress have appropriated for research
> on keragenated marlstone. So they lied a little. (And the self-deception
> of the oil companies cost them and us a few hundred billion $.
>
> So let's pick an honest, descriptive name that emphasizes what is new.
>
> Yours truly, TOM
> REED

how about the dual action stove TM

jamie

From larcon at sni.net Wed Jul 9 21:40:25 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:28 2004
Subject: Top lit gasifier trial 2 (English)
Message-ID: <v01540b05afe9cf48ccc3@[204.133.251.10]>

>Summary: A few questions on Alex' Top lit gasifier trial

Alex said today:

>I did as Ron suggested and drilled holes (4mm) in between all the 6mm
>holes. The pipe is still sitting on a wire mesh with sand as a "below
>fuel air regulator. Flame attachment to the over fire air holes was
>variable. The flame often danced at a point closer to the centre. There
>was often
>plenty of blue in the flames. The flame gathers in the centre with
>too much dead space around it.

(RWL): 1. Any distinct differences between the original 6 mm holes and
now the new (combined) situation?

2. I don't understand your control mechanism on primary air. Can
you estimate the range of turndown ratio?

(Alex):
<SNIP>
>
>We are all dancing around the tree of 'temperature' and
>'turbulence', I hope were having a good 'time'. Alex

(RWL): Me too. Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From Agnes.Klingshirn at gtz.de Wed Jul 9 21:40:22 1997
From: Agnes.Klingshirn at gtz.de (Klingshirn, Agnes, 4234)
Date: Tue Aug 31 21:35:28 2004
Subject: Sudan and GTZ (Klingshirn)
Message-ID: <v01540b03afe9c757ef02@[204.133.251.10]>

Summary: A further comment on Sudan, following earlier comments from Bess
and Larson.

Ron - yes, GTZ did some work in the Sudan in the mid-80s.
It was concentrated on cotton stalk carbonisation. At the
time it seemed to work quite well, but I do not know what
happened after the political unrest caused the project to
be closed some years agao. If someone is interested in the
old documents, we could try to dig some out. Agnes

- Es folgt das Anschreiben von owner-stoves(a)crest.org vom
07.07.1997 23:45:04 -
an: stoves(a)crest.org, Klingshirn

From larcon at sni.net Wed Jul 9 21:41:31 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:28 2004
Subject: Mirte design (Bess)
Message-ID: <v01540b07afe9d66c7a34@[204.133.251.10]>

Summary: Asking Mike Bess about his experience on stove chimney height,
interior height, stove opening area, and wood loading.

In a reply to Juan Flores' message (Re: Stove price) today related to the
Plancha stove, Mike Bess said:

>We could send you the specifications for making the moulds, the
>dimensions, and the mix, but I believe you will have to adapt it to your
>own conditions in Honduras and Nicaragua.

(RWL): Mike, I know that you carefully control various dimensions for
the Mirte. Could you comment on the criticality of:

a) height of chimney (normally none on the mitad when used with
3-stones). What is your recommended height and what happens to fuel
economy or other design criteria if you eliminate the chimney all together
or have one exiting the kitchen (as with the Plancha)?

b) fuel door opening area - the Plancha has a metal door (maybe
necessary because of their chimney, to reduce air flow.) Would you have
liked a door on Mirte? (Left out because of cost?)

c) Fuel chamber height? How critical is this parameter?

d) Fuel placement? I've been impressed with the red hot embers -
that seem to be operating a lot like charcoal - heating the mtad mostly by
radiation - but I never have really looked closely at the injera cooking
strategy. All air is traveling horizontally - no grate (Paul Hait might
recommend a diferent approach). It always seemed that the cook moved the
fuel around a lot - presumably because she could sense hot and cold spots?
Where do they put a new piece of wood when needed? (center or outside?)

e) Anything else to transfer to the plancha stove design? (How
long did it require to get comfortable that the design was "optimum")

f) Maybe you could also describe the use of the injera cover (magogo?)

Thanks in advance (still haven't received the written report which
probably has all this material in it). Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From english at adan.kingston.net Wed Jul 9 22:48:31 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:28 2004
Subject: Top lit gasifier trial 2 (English)
In-Reply-To: <v01540b05afe9cf48ccc3@[204.133.251.10]>
Message-ID: <199707100249.WAA18306@adan.kingston.net>

Dear Ron
Summary: Answers to Questions

> (RWL): 1. Any distinct differences between the original 6 mm holes and
> now the new (combined) situation?

There was a distinct lack of smoke. I assume that there was
insufficient secondary air the first time.

> 2. I don't understand your control mechanism on primary air. Can
> you estimate the range of turndown ratio?

The pipe sits on a wire mesh, with a 5cm square pattern, which is
larger than the pipe diameter. This holds the pipe up of the surface,
which in this case was a concrete block, by about 5mm. I sprinkle
sand around the perimeter of the pipe and sweep it, with a twig,
into, or away from, the 5mm space so as to control the amount of
space letting the air in. I had three to six spots open. High Tech!

I can guess at turn down, but I prefer hard data. I would say that
turn down was easier to obtain with this, than with the venturi
burner. Turndown with good performance is a challenge even for the
high tech oil and gas boys. I saw some complex gas burners, that
claimed success, at a greenhouse conference last year. Although not
directly related, these burners featured many small aim-able air
ports about 5mm in dia. through about 10mm thick material. If you
want to induce more swirl with your secondary air, some additional
cylinder wall thickness may help. If it were poured concrete, nails
could be set in the form and pulled latter to leave oriented holes.
The attached flamelets I observed surprised me by the distance that
they projected towards the centre of the chimney. The 7cm tubes of
flame lacked turbulence.

Alex

>
> (Alex):
> <SNIP>
> >
> >We are all dancing around the tree of 'temperature' and
> >'turbulence', I hope were having a good 'time'. Alex
>
>
> (RWL): Me too. Ron
>
> Ronal W. Larson, PhD
> 21547 Mountsfield Dr.
> Golden, CO 80401, USA
> 303/526-9629; FAX same with warning
>
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From phait at transport.com Thu Jul 10 01:27:33 1997
From: phait at transport.com (John Doe)
Date: Tue Aug 31 21:35:28 2004
Subject: NAME CONTEST
Message-ID: <199707100519.WAA07383@brutus.transport.com>

>Tom Reed wrote:
>>
>> TOM REED, CSM, reedtb@compuserve.com
>> ELK et al:
>>
>> Sounds like you are making great quantitative progress with what you call
>> the "two can stove". Congratulations - push on! Here are a few comments
>> for your consideration.
>>
>> You asked what happens to the charcoal if it is not extinguished when the
>> volatiles have all been consumed. If you put a thermocouple in the middle
>> of the charge it will show you
>>
>> a) initially room temperature air passing by on the way up to the "flaming
>> pyrolysis" zone (yes, there is a flame buried in the pile - we built a
>> "transparent gasifier" with gold reflective insulation and could observe
>> it)
>>
>> b) a very rapid rise in temperature to about 500 C as the flame approaches
>> the thermocouple
>>
>> c) very little drop in temperature as the volatile flame approaches the
>> bottom grate
>>
>> d) an immediate sharp rise in temperature as charcoal begins to burn
>>
>> So, one TC (or dial gauge thermometer) reveals the history quite
>> accurately. I recommend that we all use such a buried TC for our tests
>>
>> ~~~~
>> NAME OF STOVE CONTEST:
>>
>> NAME OF STOVE:
>>
>> It has been most amusing to follow the changing names given this stove. I
>> initially (in 1985, patent memos to SERI/NREL) called it an
>> "UPSIDEDOWNDRAFT GASIFIER" stove by analogy to the conventional "downdraft"
>> gasifier, well known during WWII and also to emphasize that it cooked with
>> GAS. After a year or two I realized the "upsidedowndraft", while colorful,
>> was not informative to non-English speaking people (like Harry LaFontaine).
>> So I changed to calling it the "Inverted downdraft gasifier-stove". When
>> Fred Hottenroth produced a commercial model he called it a GASFIRE stove
>> (1989). I have also called it a WOOD-GAS stove, with strong emphasis on
>> GAS to avoid confusion with a few thousand wood stoves built through the
>> ages. Gasifier stoves are NEW (and include the "J" stove of
>> Verhart-Eindhoven-Antal).
>>
>> When Ron Larson called me to ask about charcoal making stoves he renamed it
>> "a CHARCOAL MAKING" stove (1992). Others call it the TOP LIGHTED stove.
>> Now you call it the TWO CAN" stove.
>>
>> It seems to me we have here the "blind men and the elephant" syndrome.
>> Each person sees what he/she thinks is important. Coming from gasifiers
>> and having used gas stoves, I think WOOD-GAS STOVE (as opposed to WOOD
>> STOVE) is most descriptive and exciting. Ron comes from Ethiopia where the
>> possibility of producing charcoal (always a nuisance in my eyes) was the
>> most important feature.
>>
>> Now you use TWO CAN STOVE to describe it. Does the fact that it can (but
>> not necessarily is) be made from two tin cans best catch the essense?
>>
>> I suggest we all submit our best choices for a single name to catch the
>> essense. Ron can collect the names and we can all vote. Majority wins and
>> we all sink or swim with the result.
>>
>> ~~~~~
>> Fussing over names may seem nit-picking. Nonsense. A good name is almost
>> as important as a good product.
>>
>> OIL SHALE is not truly a shale, nor does it contain oil. It is keragenated
>> marlstone. How much funding would Congress have appropriated for research
>> on keragenated marlstone. So they lied a little. (And the self-deception
>> of the oil companies cost them and us a few hundred billion $.
>>
>> So let's pick an honest, descriptive name that emphasizes what is new.
>>
>> Yours truly, TOM
>> REED
>
>
>
>how about the dual action stove TM
>
>jamie
>How about the Tandom Stove(Two cans)? How about the
Tri-Stove(wood/gas/charcoal)

Sincerely,
Paul ( John Doe )

From E.Moerman at stud.tue.nl Thu Jul 10 07:16:27 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:28 2004
Subject: Turbulent & diffusion blue flames
Message-ID: <4609.s335192@popserver.tue.nl>

Alex:
> I would like to tie this back to the small stove
> experiments. The regular carbon steel stove pipe that the combustion
> chamber/ chimney above the venturi is made of, is flaking ( what is
> this flaking process called) due to the high heat and shows that it
> is not an adequate material for the job. How much would stainless
> steel add to the combustion dynamic due to its reflectivity? This
> must tie back to the flame emmisivity and absorbtivty, and perhaps
> its colour. My gut feeling is that this is all of secondary
> I'mportants compared to that of material durability.

Etienne:
We used stainless steel for our downdraft stove. Still problems with
durability, especially of the grate. Flat stainless steel plates can not
really be used since they will deform badly and lead to cracks in the
welded seems. Don't bother about the reflectivity. The high temperatures of
the steel and the volatiles lead to a brownish-grey color.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From BeedieD at Cardiff.ac.uk Thu Jul 10 13:29:14 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:28 2004
Subject: CV of gases evolved during charcoal kiln steaming phase
Message-ID: <395050C05F3@nrd1s.cf.ac.uk>

Summary: what is CV of early gases evolved from charcoal kiln ?

DB:
> >Regarding the following excerpt I've snipped from your recent
> >posting, can you suggest a figure for the CV of the gases evolved from
> >a charcoal kiln during the early (steaming) part of the cycle? [Net
> >CV (i.e. assuming combustion product moisture is in gaseous form) is
> >probably the most useful measure.]
> >?
AJH
> I have not any way of measuring this, actually (as you infer)as it contains
> visible water vapour there would be some energy consumed in turning these
> droplets to steam at approximately 2.7-2.9 mJ/kg depending on the flue
> temperature. At this stage wood is being burned to drive off moisture in the
> charge, that is why Ronal suggested it is highly polluting as its CV is not
> high enough to sustain flaring because of dilution of any pyrolysis gasses
> by combustion products, steam amd free water droplets. This is why I
> suggested using bone dry wood, obviously not practical in the field and then
> we could calculate input CV of wood at 18.6 mJ/kg less output CV of charcoal
> at 30mJ/kg the differences would be in 1)heat loss from system, 2)sensible
> heat of charcoal 3)sensible heat of gasses 4)CV of gases. For instance if
> 1kg of wood reduced to .25kg of charcoal then energy difference is 11.1mJ.
> If the kiln temperature was 300c then we would know .75kg of gases and .25kg
> of charcoal at 300C at their respective specific heats were accounted for.
> The balance should be in the losses from the vessel ( I wish to move away
> from kilns, too much black art involved), which could be minimised with
> insulation, and chemical energy of the gases, or am I being too simplistic.
> Not everyday calculations for a woodman!
> AJH

DB:
Not everyday calculations for anyone else either I would guess.
This approach would also produce a value averaged over the cycle.
I am specifically interested in the CV of the 'steaming' gases -
although they will not sustain flaring owing to the high proportion of
evaporated moisture and combustion products, they may nevertheless
possibly have enough energy to sustain combustion in a good low-CV
burner. Has anyone tried this ? Low-CV burners have improved.

This is clearly not a natural draught proposition - a fan is needed
for the burner - but it would be a way of getting a clean process
without support fuel - if the gases have a net CV above about 1MJ/kg.

The forced draught for the burner could be arranged to induce a
draught in the kiln which I surmise might give additional advantage
control-wise.
**********************************************
** **
** Note temporary home telephone number !! **
** **
**********************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From ahe1 at cableol.co.uk Fri Jul 11 01:45:15 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:28 2004
Subject: Top-lit charcoal kiln (Heggie)
Message-ID: <9707110545.AA11460@mars.cableol.net>

Summary: proposed testing of a top-lit large charcoal kiln and partial
success with flaring existing chimneys

>(RWL): Andrew - I think this is great news; thanks for going out on a limb.
>I hope you realize that the following comments are not at all from
>experience or knowledge of your operation - only an extension of working at
>the 1/2 meter scale (with a total pyrolyzing time then of about 2 hours.
>Your's should take at least 4-5 hours. What is your present firing time
>for this size kiln?
Well I wanted to try anyway, we were stopped burning because of complaints
last night so there is some urgency in this. Remember we are using fresh
material so 16hrs is not unusual, 24 with dry 30 with wet with the larger
kilns from our previous sites where the operator camped out to control the
burn. In our current site we throttle down at night by obstructing the inlets.
>
> 1. Could you describe the height or pitch of this conical roof?
Shallow about 30cms height
>
> 2. What diameter and length are the existing outer stove pipe pieces?
100mm*1.2m but we have other chimneys for the larger kilns 150mm*2.4m
<snip>

>I think the fines could cause a problem if they fall lit to the bottom.
Very good point
>think the brands and lighting should be over the whole upper surface - not
>just in the middle.
Yes point taken
>
> Maybe lighting can be from the edge at the same time - maybe using
>a propane torch. If the wind blows out the flame you want to be able to
>quickly relight the pyrolysis gases (which will be instantaneous).
we will light with the cone off and then drop it on
>
> During initial ignition, the bottom vents should all be open -
>later they should be closed back to the point you feel comfortable with the
>flame size.
Point taken

>(RWL): 1. The two concentric tube design may be overkill at first. I
>think this stove pipe will get orange-to-yellow hot and ordinary stove pipe
>may not handle that temperature. You may want only one layer to cool it
>down.
Yes, I see now that you mean secondary air will be required to form an
"inverted" air-gas flame at the lip and the flaring will be tertiary. I
understand now that the cone and chimney will become very hot, I will limit
this by lowering the lid with a pry bar. I had assumed both primary and
secondary air would come from the bottom.
>
>2. But the idea of pre-heating may be a good one - if I understand your
>suggestion. I would hope that all combustion is complete inside the
>chimney, but with too short a chimney this will not happen - and then
>preheating more "tertiary" air might help.

When I arrived this morning the kilns had been shut down at midnight because
of smoke nuisance, on a hot sultry evening, which had clung to the ground
over a considerable distance. When restarted the smoke was copious and
yellow tinted rather that just visible water vapour. As an experiment I lit
an oil soaked rag and flared the chimneys, 2 of 4 helld a flame for several
miutes, one hour later all 4 flared one for 30mins, the flame blew out in a
gentle breeze. These could be relit for an hour or more but the flame would
not hold on the windward chimneys. Once flaring the smoked dimished to a
blue haze. The flme was barely visible in sunlight, when overcast it was
blue near the chimney and a deep orange/red and lazy up to 1m from the
chimney. Reignighting was easy with oxy-acetylene torch and adding oxgen via
the cutting nozzle seemed to increase the intensity the velocity of the
chimney gasses was sufficient to snuff the oxy-acetylene torch if immersed
in the stream.. The flame was silent unlike a bunsen burner. Next I made a
brazier of wire and placed it with burning charcoal in the top of the
chimney, the charcoal was extinguished. I decided we needed to mixe in some
aire so I placed a 1m lengt of larger pipe overlapping the chimney with a
numbe of slits in it. Whent the torch was applied the gas burned in the pipe
for 10secs after the torch was removed and the output became dramatically
smokeless. Towards the end of the day prior to shut down it became difficult
to light the stacks, though by then the smoke was minimal.
>
>3. My guess is that you will eventually settle on a chimney of between 1-2
>meter height. The right height will give the proper draw of secondary air,
>with the bottom air ports controlling the primary air (which controls the
>intensity of the chimney flame. It would be good in the first experiment to
>try several stove pipe heights to see which works best - but exchanging or
>lengthening the chimney during operation may be pretty hazardous. True?
Well that depends but I think we can handle the chimney with two poles as
double ended "chopsticks" to lift it on and off as long as the locating
spigot is good enough.
>(The draft you get with a 1-2 meter chimney filled with burning gases will
>be much more than in your present approach, so you may have difficulty
>keeping the primary air low enough.)
>
>4. You say "...or shall we allow gasses to escape via a propped lid and
>flare the slit so formed?" I don't believe you will find sufficient draft
>this way and the flame will be unstable with a wind. I think you must have
>a slit and the secondary air flow will all be inward - hopefully with flame
>holding right at the lip. Because of the draft from the 1-2 meter chimney,
>all of the pyrolysis gases are swept inward and up. There should be no gas
>leakage outward.
Yes I had not appreciated this at first.
> The width of this gap and how to vary it (and eventually close it)
>will require some experimentation. I suppose a crowbar will work, with
>wedges . I think 1-4 cm should be the range you need to try (maybe start
>at 2). Maybe you could start with one side at 1 cm and the opposite side
>at 3 or 4. Looking for good flame holding would seem to be the criteria
>for appropriate gap size.
understood

>
>(RWL): Rephrased: " Air would enter through the six inlets and, after
>traveling horizontally at first, will rise through the vertically stacked
>wood to the downward-moving pyrolysis zone. There it creates moderately
>hot pyrolysis gases (some of which travel through the wood) which are
>flared near the secondary air inlet with the addition of inward traveling
>secondary air."
Yes this is better to understand

>(RWL): 1. First being a little picky here with the word "burning". I
>presume this refers to the diffusion flame in the cone region where the
>right ratio of pyrolysis gas and oxygen are in contact. At some later
>stage - where you might be trying to transfer this pyrolysis gas to a
>bakery or brick kiln for ignition there, a blower would replace the natural
>draft.
Yes I will try to refer to the significant carbonising reaction as the
pyrolysis front and restrict burning to the oxidising of the evolved gasses.
> 2. The last phrase: " leaving charcoal formed earlier in a reducing
>atmosphere above" doesn't sound quite right. I'd say either: "leaving
>charcoal" or "with the resulting pyrolysis gases traveling upward past
>charcoal formed earlier".
Yes this last phrase is what I meant, I also meant to convey the reason the
charcoal so formed would not oxidise, because any oxygen would be depleted.
> 3. Part of the issue here is how long it takes to form charcoal
>all the way to the inside of a thick piece. This is done partly via
>conduction of heat inward, with some of the gases coming out radially, but
>most gas (I think) coming out upward vertically through the already
>produced charcoal. I think little of this interior (to a wood piece)
>charcoal production uses much of the incoming oxygen. There will be some
>splitting of the wood caused by expansion of interior trapped moisture and
>this will help move heat inward also through hot gas contact. That portion
>of the process which is exothermic of course helps further heat other
>interior parts of the wood block.
By radiation!
<Snipped all good points>

>
>(RWL): If you can get a "fire" started, it should go to completion. I
>hope you can get the wood as dry as possible. Can you estimate anything
>now about the likely moisture content? If the wood looks or feels wet, I
>wouldn't try it. But trying one section with some wet wood would be an OK
>experiment.
I am afraid this will be fresh felled wood at an average 100% mc as referred
to the dry weight of wood i.e. 50% of the charge will be wood. I will try
again in the Autumn when we move back to a woodland setting.
<Good points snipped>
> You must be able to put a "pot" or something over the chimney of
>course. I have successfully used a wet rag over the hole before placing
>the upside-down "pot". If you get lots of smoke exiting through the
>secondary air slit, you may have to open up and spray water inside. Maybe
>using sand also. But maybe the smoking will stop if you have only
>successfully closed all the lower air ports.
I would assume that smoking will finish by the time of shut down
>
> I hope others like Tom, Elsen, and Alex can correct or add to these
>comments. The things I would worry about most are getting a good draft
>(enough height) and finding ways to be flexible in the chimney height and
>width of the secondary air slit.
Conventional stove chimneys are stackable in 1m lengths, for this purpose I
will use spiral ducting and from what you say will expect it to burn out.
AJH

From english at adan.kingston.net Fri Jul 11 07:04:27 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:28 2004
Subject: Top-lit charcoal kiln (Heggie)
In-Reply-To: <9707110545.AA11460@mars.cableol.net>
Message-ID: <199707111103.HAA01619@adan.kingston.net>

Dear Andrew +
Summary: Necessary chimney height inversely proportional to
density ( ie: temperature) of gasses.
.
> > I hope others like Tom, Elsen, and Alex can correct or add to these
> >comments. The things I would worry about most are getting a good draft
> >(enough height) and finding ways to be flexible in the chimney height and
> >width of the secondary air slit.
> Conventional stove chimneys are stackable in 1m lengths, for this purpose I
> will use spiral ducting and from what you say will expect it to burn out.
> AJH

The more you develop a well mixed and contained flame within the
chimney, which could now be called a combustion chamber, the shorter
the chimney will need to be. This can be an accelerating process up
to the flow limits of the chimney, as in a creosote chimney fire.
The problem is that this is not the "startup" condition, indeed you
have a constantly changing condition during your long process.

The venturi arrangement that I have used seems to have a built in (
but not by design) regulatory effect on the draft below the venturi.
As the flame intensity and draft increases above the venturi, the
more the venturi draws secondary air into its mid section squeezing
the throat diameter and the potential draft below the venturi.
Someone needs to try this on a larger scale than I have. Andrew?

This is, of course, all conjecture. I probably don't need to say this,
as sure as you recognize my signature.

Alex
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From REEDTB at compuserve.com Fri Jul 11 09:14:24 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:28 2004
Subject: STOVE PRESS???
Message-ID: <199707110914_MC2-1AAD-7D9E@compuserve.com>

Some of you may know that I operate a small press, making about a dozen
books on gasification available (see below). I also am willing to reprint
other books that I have.

It costs me $10 to $15 per large book to make 10-20 copies at a time,
spiral bound, as good as the original. I sell the larger books for
$20-$30. I lost money on this for 5-6 years, but lately I have been
breaking more than even. I am now adding ISBN numbers and am listed in
Amazon.Com.

Is it possible that someone would like to start a similar STOVE press to
keep the "classics" available for members and others. Or alternatively Ron
and I could assemble a similar list for stoves and probably and I would
take it under my 501-c-3 wing.

Opinions?

Yours truly, TOM REED
~~~~
BOOKS FROM THE BEF PRESS

PURPOSES OF THE BIOMASS ENERGY FOUNDATION PRESS

Biomass energy and particularly biomass gasification is a field where
publications are often difficult to find. Our aim is to make available
information on biomass at reasonable prices. We list here our newer
releases and current titles and include an order form. We will also make
available at $0.15/page other papers from our extensive library of
technical papers on gasification dating back to the turn of the century.
We also act as a clearinghouse to locate technical assistance for biomass
projects. Thomas
B. Reed
HANDBOOK OF BIOMASS DOWNDRAFT GASIFIER ENGINE SYSTEMS
T. B. Reed and A. Das Over a million wood gasifiers were used to power
cars and trucks during World War II. Recent concern about cost and
availability of liquid fuels has reawakened interest in this technology.
Yet, after a decade of interest, there are only a few companies
manufacturing gasifier systems for specialized applications. The authors
have spent more than 12 years working with various gasifier systems,
primarily at the Solar Energy Research Institute (SERI). In this book they
discuss all the factors that must be correct to have a successful "gasifier
power system."

Chapters in the book include: Principles of Gasification; Gasifier Designs;
Gasifier Fabrication & Manufacture; Gasifier Fuels; Instrumentation &
Control; Gas Testing; Engine Adaptation and Operation; Gasifier Systems;
Safety & Environmental Factors; and Decision Making. The book was
originally conceived as an aid to farmers and mechanics who want to build a
"home gasifier" to power generators, pumps, tractors and mills. However,
it has expanded far beyond that scope to be a major reference for anyone
interested in producing power from wood and biomass wastes. 200pp
$25.00

FUNDAMENTAL STUDY AND SCALEUP OF THE AIR-OXYGEN STRATIFIED DOWNDRAFT
GASIFIER - T. B. Reed, M. Graboski and B. Levie. In 1980 the Solar Energy
Research Institute initiated a program to develop an oxygen gasifier to
make methanol from biomass. A novel 1 ton/day gasifier was designed and
studied for five years at SERI on air and oxygen. Now a 25 ton/day
gasifier has been operated on both air and oxygen. This book describes the
theory and operation of the two gasifiers in detail and also discusses the
principles and application of gasification as learned in eight yearsby the
author-gasifier team. Initially published by DOE with lavish
illustrations. 250pp........ .$25.00

CONTAMINANT TESTING FOR GASIFIER ENGINE SYSTEMS - A. Das Long engine life
and reliable operation requires a gas with less than 10 mg of tar and
particulates per cubic meter (10 ppm). The simplified test methods
described here are adapted from standard ASTM and EPA test procedures for
sampling and analyzing char, tar and ash in the gas.
32pp.................................. ..$8.00

TREES - Jean Giono. While we strongly support using biomass for energy, we
are also very concerned about forest destruction. This delightful true
story says more than any sermon on the benefits and methods of
reforestation. 8pp.. ...$1.00

TREE CROPS FOR ENERGY CO-PRODUCTION ON FARMS
Anyone interested in using biomass for energy should know about the
enormous potential for raising trees along with food crops as an energy
source. This book is reprinted from a conference held by the Solar Energy
Research Institute, convening experts in this field to evaluate potential
crop species and to examine practical systems for the
economical production of energy from wood species. 260 pp
............................................................ ..$20.00

The BEF Press, 1810 Smith Rd., Golden, CO , 80401
303-278 0558;FAX: 303 278 0560E-mail 73002.1213 @ Compuserve.com

***************************************************************************
*************

THE BIOMASS ENERGY FOUNDATION PRESS ORDER BLANK

No. Cost
HANDBOOK OF BIOMASS DOWNDRAFT GASIFIER ENGINE SYSTEMS: T. Reed and A.
Das, (SERI-1988). 140pp (see over) $25.00. ___ ____

GENGAS: THE SWEDISH CLASSIC ON WOOD FUELED VEHICLES: English translation,
(SERI-1982), edited T.Reed, D. Jantzen and A. Das, with index. This is the
"Old Testament" of gasification, written by the people involved in
successfully converting 90% of transportation of WW II Sweden to wood
gasifiers. Valuable practical and theoretical information. 340pp.
$25.00...___ _____

PRODUCER-GAS: ANOTHER FUEL FOR MOTOR TRANSPORT: Ed. Noel Vietmeyer (The
U.S. National Academy of Sciences-1985) A seeing-is-believing primer with
historical and modern pictures of gasifiers. An outstanding text for any
introductory program. 80pp $8.00...___
_____

FUNDAMENTAL STUDY AND SCALEUP OF THE AIR-OXYGEN STRATIFIED DOWNDRAFT
GASIFIER:
T. Reed, M. Graboski and B. Levie (SERI1988).290pp (see over) $25.00...___
_____

CONTAMINANT TESTING FOR GASIFIER ENGINE SYSTEMS: A. Das (1989).32pp (see
over) $8.00...___ ___

TREE CROPS FOR ENERGY CO-PRODUCTION ON FARMS:. 260 pp (see over)
$20.00...___ _____

STATE-OF-THE-ART FOR SMALL SCALE GAS PRODUCER-ENGINE SYSTEMS: by A. Kaupp
and J. Goss. (1984) Updates GENGAS and contains engineering data
indispensable for the serious gasifier projects.
278 pp $25.00...___ _____

GASIFICATION OF RICE HULLS: THEORY AND PRAXIS: A. Kaupp. Applies
gasification to agricultural residues in addition to rice hulls. 303
pp,$25.00...___ _____

WOOD GAS GENERATORS FOR VEHICLES: Nils Nygards (1973). Translation of
recent results of Swedish Agricultural Testing Institute. 50 pp.
$4.00...___ _____

THE PEGASUS UNIT: THE LOST ART OF DRIVING WITHOUT GASOLINE: by Niels A.
Skov and Mark L. Papworth. Detailed drawings of various gasifiers and
systems from World War II. 80 pp $15.00...__
______

BIOMASS TO METHANOL SPECIALISTS' WORKSHOP: Ed. T. B. Reed and M. Graboski.
Expert articles on biomass to methanol, the clean liquid fuel for the 21st
century. 331 pp $30.00...___ _____

CONSTRUCTION OF A SIMPLIFIED WOOD GAS GENERATOR: ...by H. LaFontaine (1989)
- Over 25 drawings and photographs on building a gasifier for fueling IC
engines in a Petroleum Emergency. Originally published by the Federal
Emergency Management Agency (FEMA) as RR28. 68 pp
$10.00...___ ____

TREES: by Jean Giono, 1953. A delightful story which says more than any
sermon on the need for reforestation.
8 pp $1.00...___ _____

<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
BOOK
TOTALS.....................................................................
......................................................... ___ ______
Add $3 handling/order + $1.50/book postage* $3 + ________= ________
TOTAL ENCLOSED..__________

Name______________________________________________________________________A
ddress___________________________________________________________________
Mail orders to The Biomass Energy Foundation Press (BEFP), 1810 Smith Rd.,
Golden, CO 80401; FAX 303-278 0560;call 303 278 0558;E-mail
73002,1213@Compuserve.com. **Shipping: $2.50/book to Canada and Mexico,
all other foreign $8/book. 10% discounts on orders for 3 or more books.
Distributor inquiries welcomed. Please include check or money order with
your order. Foreign orders remit by postal order of electronic transfer to
Bank Rte No.: 102 0000 76; Acct. No. 300 800 2911....Thanks for your
order.

From REEDTB at compuserve.com Fri Jul 11 09:14:28 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:28 2004
Subject: Pictures are on Web - NOT
Message-ID: <199707110914_MC2-1AAD-7D9C@compuserve.com>

Dear Alex:

For the last few days I have not been able to contact
http://www1.kingston.net/~english/Stoves.Html
(though I did a month ago).

What have I done wrong?

I have some pictures to send you. Thanks a big BUNCH for helping us with
this. What kind of scanner do you use? I am supposed to get one from my
son this month.
~~~~~
Thanks also for your CO measurements ( I presume ppm?). Surprisingly high
from "clean" burning equipment, wow for stove.

It is important to minimize CO in combustion products. However, it is also
important to keep perspective on the human ability to breathe large
amounts. I believe the cigarette inhaler regularly gets 300 ppm CO. In
the Swedish Gen-Gas book are listed

% Saturation of Symptoms at Rest and During Exertion
Blood

0-10 None None
10-20 None Dizziness, heart pounding
20-30 Headache? Headache
30-40 Headache, pulse Dizziness, fainting,
unconscious?
40-50 Nausea, vomiting, dizziness, unconsciousness....
50-60 Deep unconsciousness...
60-70 Possible death
70-80 Respiratory failure and death....

This was published during the period when over 80,000 civilian vehicles
were operating on wood gas which contains typically 20-30% CO. Too bad we
can't easily tell % saturation in blood.

It is useful to distinguish between "thermodynamic" CO, generated when
there is not enough oxygen to make CO2 and "prompt" CO, the CO that comes
during pyrolysis, even with no oxygen at all. Your rick burn probably made
lots of both.

Yours truly, TOM REED

From english at adan.kingston.net Fri Jul 11 12:30:12 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:28 2004
Subject: Pictures are on Web - NOT
In-Reply-To: <199707110914_MC2-1AAD-7D9C@compuserve.com>
Message-ID: <199707111630.MAA10291@adan.kingston.net>

Dear Tom+
Summary : Scanner stuff and Health concerns about Emissions

> I have some pictures to send you. Thanks a big BUNCH for helping us with
> this.

AE: I have gained a great deal from this experience. There is more
that can and should be done. I look forward to your pictures.

> What kind of scanner do you use? I am supposed to get one from
>my son this month.

AE: I have an out of date ScanMaker II from Microtek. I thought I was
getting a deal at the time but ended up spending allot of time making
it work. It is essentially a bottom- of-the-line flat bed, but it
has been behaving lately. Microtek sells similar models for just
under $200 US. I believe that black and white hand scanners are
under $50 US.

> ~~~~~
> Thanks also for your CO measurements ( I presume ppm?). Surprisingly high
> from "clean" burning equipment, wow for stove.

AE: You presume correctly.

>
> It is important to minimize CO in combustion products. However, it is also
> important to keep perspective on the human ability to breathe large
> amounts. I believe the cigarette inhaler regularly gets 300 ppm CO. In
> the Swedish Gen-Gas book are listed
>
> % Saturation of Symptoms at Rest and During Exertion
> Blood
>
> 0-10 None None
> 10-20 None Dizziness, heart pounding
> 20-30 Headache? Headache
> 30-40 Headache, pulse Dizziness, fainting,
> unconscious?
> 40-50 Nausea, vomiting, dizziness, unconsciousness....
> 50-60 Deep unconsciousness...
> 60-70 Possible death
> 70-80 Respiratory failure and death....
>
> This was published during the period when over 80,000 civilian vehicles
> were operating on wood gas which contains typically 20-30% CO. Too bad we
> can't easily tell % saturation in blood.

AE: It may be that the largest share of health problems related to
stoves is due to the particulates, PAH's and VOC's. (Poly aromatic
hydrocarbons and volatile organic compounds) I am just as
interested in knowing what the comparative levels are of those are,
but am not about to run off and buy the necessary equiptment to find
out. There are other quieter folks doing that. I would be equally
interested in knowing if there is any clear established relationship
between the co-factors of time/temperature/turbulence and non-fly ash
particulates, PAH's and VOC's. The EPA in the US is seems more
focussed on these, as compared with CO emissions.. For the
combustion of wood gasses, is a CO/CO2 of .001 or less accompanied by
low levels of these other toxins ?

> It is useful to distinguish between "thermodynamic" CO, generated when
> there is not enough oxygen to make CO2 and "prompt" CO, the CO that comes
> during pyrolysis, even with no oxygen at all. Your rick burn probably made
> lots of both.

AE: I'm not sure what your point is.
It is possible, even likely, that gasses had not completely
finished burning at the sample point, which would result in a higher
reading.

Glad to be here, Alex

>
> Yours truly, TOM REED
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From larcon at sni.net Fri Jul 11 23:37:47 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:28 2004
Subject: Top-lit charcoal kiln (Heggie)
Message-ID: <v01540b00afebeff6da1e@[204.133.251.10]>

>Summary: {Continued on] proposed testing of a top-lit large charcoal kiln
>and partial success with flaring existing chimneys

On July 11, Andrew said:

> (snip> Remember we are using fresh
>material so 16hrs is not unusual, 24 with dry 30 with wet with the larger
>kilns from our previous sites where the operator camped out to control the
>burn.

(RWL): I am quite worried about this amount of moisture. Could you dry
some by stacking outside of a regular firing? Or just delay a bit to get
dryer material?

<snip>

(Andrew): >we will light with the cone off and then drop it on

(RWL): One reason to light with the cone on is that you get a tremendous
boost from the meter or so of chimney. You will get little draw through
the wood pile without the chimney. I would pretty strongly recommend
starting with the lid in place if at all possible.

(Andrew):
>Yes, I see now that you mean secondary air will be required to form an
>"inverted" air-gas flame at the lip and the flaring will be tertiary. I
>understand now that the cone and chimney will become very hot, I will limit
>this by lowering the lid with a pry bar.

(RWL): 1). I wouldn't say that "flaring will be tertiary". In the smaller
charcoal-making stoves, there is no tertiary air. Your "inverted air-gas
flame at the lip" is what I have been calling a "flare".

2). I have been doing no control of the power level with the
secondary air slit - only with the primary air supply. This is the
"turn-down ratio" in stoves - so you might be able to go from a 4-5 hour
run to 12 or more hours (assuming dry wood) - just by controlling the
primary air supply. Control the secondary air slit to get the right amount
of excess air (if you could measure CO2 - I gather that 10-12 % each of O2
and CO2 are considered acceptable).

The more the primary air, then the more pyrolysis gases. The
larger amount of pyrolysis gas gives a hotter flame and a better "vacumm"
and the more secondary air drawn in. The amount of secondary air seems to
be somewhat self regulating.

(Andrew):> I had assumed both primary and secondary air would come from
the bottom.

(RWL): Actually, there is some advantage to drawing some of the required
secondary air from the bottom. This can be done using some (all?) of your
exterior chimney pipes - stacked vertically just like a piece of wood
(using rocks or something to ensure they are not blocked) . These will
draw secondary air from the bottom up past the pyrolysis zone and allow
flame holding on these chimney pipe rims - at the upper level of the wood.
There will not be a big draft here because this secondary air does not get
very hot.

(Andrew):
>When I arrived this morning the kilns had been shut down at midnight because
>of smoke nuisance, on a hot sultry evening, which had clung to the ground
>over a considerable distance. When restarted the smoke was copious and
>yellow tinted rather that just visible water vapour. As an experiment I lit
>an oil soaked rag and flared the chimneys, 2 of 4 held a flame for several
>minutes, one hour later all 4 flared one for 30mins, the flame blew out in a
>gentle breeze. These could be relit for an hour or more but the flame would
>not hold on the windward chimneys.

(RWL): I gather the flame was only at the top of these chimneys, with no
lower secondary air?. Were these the 100 mm or the 150 mm dia? I believe
that the main issuwe is flame holding. Does anyone know how gas flaring
works at refineries? They must have some good means of flame holding.

If you could introduce secondary air at the bottom of these present
chimneys, you might have a better flame (inside rather that outside the
chimney). The draft will go way up.

(Andrew):
> Once flaring the smoked dimished to a
>blue haze. The flme was barely visible in sunlight, when overcast it was
>blue near the chimney and a deep orange/red and lazy up to 1m from the
>chimney. Reignighting was easy with oxy-acetylene torch and adding oxgen via
>the cutting nozzle seemed to increase the intensity the velocity of the
>chimney gasses was sufficient to snuff the oxy-acetylene torch if immersed
>in the stream.

(RWL): I'm surprised at this snuffing, but don't know enough about welding
torch operation. I was thinking you would have had fairly low flow - what
was the chimney height? Any other thoughts from anyone?

(Andrew)
> The flame was silent unlike a bunsen burner. Next I made a
>brazier of wire and placed it with burning charcoal in the top of the
>chimney, the charcoal was extinguished.

(RWL) - no oxygen in this exhaust gas. I have trouble with matches sometimes.

(Andrew):
I decided we needed to mixe in some
>aire so I placed a 1m length of larger pipe overlapping the chimney with a
>number of slits in it.

(RWL): I'm not sure whether the slits are in the outer pipe or the inner
pipe. Can you describe where the pyrolysis gases and air are mixing and
where first flaring and flame holding are occurring.

(Andrew):
When the torch was applied the gas burned in the pipe
>for 10secs after the torch was removed and the output became dramatically
>smokeless. Towards the end of the day prior to shut down it became difficult
>to light the stacks, though by then the smoke was minimal.

(RWL): Was the extinguishment always attributable to the wind?

<snip>

(Andrew):
>Well that depends but I think we can handle the chimney with two poles as
>double ended "chopsticks" to lift it on and off as long as the locating
>spigot is good enough.

(RWL): Good luck - I recommend some prior practicing. Anything there to
catch a hook on?

<snip>
(Andrew):
>I am afraid this will be fresh felled wood at an average 100% mc as referred
>to the dry weight of wood i.e. 50% of the charge will be wood. I will try
>again in the Autumn when we move back to a woodland setting.

(RWL): I'm nervous about this amount of moisture - but I guess it is worth
an experiment.

<snip>

(Andrew):
>I would assume that smoking will finish by the time of shut down.

(RWL): Sometimes - but often the flame will go out and you can't restart
(mostly CO2 coming now) and still a lot of smoke. I urge being ready for a
lot of smoke at shutdown time.

(Andrew):
>Conventional stove chimneys are stackable in 1m lengths, for this purpose I
>will use spiral ducting and from what you say will expect it to burn out.
>AJH

(RWL): Or at least pretty darn hot. Hopefully,you can cut the primary air
back some to get the pipe temperature pretty low (and take longer). I think
the pipe will survive, if your spiral ducting is of a similar thickness to
stove pipe. I don't see that much degradation on old steel cans.

Again the best of luck. I hope anyone else on the list who has
alternative recommendations will speak up. I especially wish I knew more
about flame holding.

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From english at adan.kingston.net Sat Jul 12 08:32:55 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:28 2004
Subject: Top-lit charcoal kiln (Heggie)
In-Reply-To: <v01540b00afebeff6da1e@[204.133.251.10]>
Message-ID: <199707121233.IAA07607@adan.kingston.net>

Dear Ron, Andrew, +

Summary: Flame Holding in an Oil Burner is done with a pilot light or
through various obstructions and vanes which force the flame to
circulate back into the middle of the flame.

> Again the best of luck. I hope anyone else on the list who has
> alternative recommendations will speak up. I especially wish I knew more
> about flame holding.
Older pressurized oil burners used a continuous spark/arc across
electrodes as a pilot light. More modern oil burners have dispensed
with the spark (after start up) and use a cone shape, or flat disc
in the case of our Riello burner, placed in the middle of the air
flow which causes some back eddies. These obstructions usually have
radial slits all opened in one direction to add swirl. With these
burners, the flame appears to cling to the obstruction, hence their
named 'flame retention heads'. In unrelated experiments, I have
used these oil burner assemblies as ignition systems with high
velocity air (roughly at 100mph), fully expecting
the flame to be blown off, but it didn't happen.
I too would like to hear about petroleum industry flares. My guess is
that they use high pressure which sets up a dynamic which negates
the effects of wind. Balloonists have a novel approach, they operate
as part of the wind. Can you picture large floating pyrolysis piles?

However with your low pressure needs you may wish to try and complete
combustion in the pipe, perhaps in a widened section. Then in an
additional section of chimney you could install a barometric draft
controller. This is standard equiptment on household oil furnaces,
used to prevent excess draft effects on the furnace. They are simple
and cheap and could even be home made.

I think that flaring at a single point might be something worth
considering. Investing in a single larger flame may offer some
stability.
Good luck, I might start to play here.
After the hay is in. Alex

> Regards Ron
>
> Ronal W. Larson, PhD
> 21547 Mountsfield Dr.
> Golden, CO 80401, USA
> 303/526-9629; FAX same with warning
>
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From ahe1 at cableol.co.uk Sat Jul 12 09:18:17 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:28 2004
Subject: Top-lit charcoal kiln (Heggie)
Message-ID: <9707121318.AA08969@mars.cableol.net>

>>Summary: {Continued on] proposed testing of a top-lit large charcoal kiln
and partial success with flaring existing chimneys

>
>(RWL): I am quite worried about this amount of moisture. Could you dry
>some by stacking outside of a regular firing? Or just delay a bit to get
>dryer material?

(Andrew): Not on the present site because of safety considerations, as I
said we will move back to a situation where drier material is available in
the Autumn.

>(RWL): One reason to light with the cone on is that you get a tremendous
>boost from the meter or so of chimney. You will get little draw through
>the wood pile without the chimney. I would pretty strongly recommend
>starting with the lid in place if at all possible.

(Andrew) This only takes seconds and I believe will be insignificantly different

>(RWL): 1). I wouldn't say that "flaring will be tertiary". In the smaller
>charcoal-making stoves, there is no tertiary air. Your "inverted air-gas
>flame at the lip" is what I have been calling a "flare".

(Andrew) I was referring to any remaining combustion which takes place above
the chimney, tertiary air being supplied by atmosphere, I now understand you
expect all gases to be oxidised in the cone and chimney and hence there will
be nothing left to form a flame " an area of combining gases" above the chimney.
<snip>
> The more the primary air, then the more pyrolysis gases. The
>larger amount of pyrolysis gas gives a hotter flame and a better "vacumm"
>and the more secondary air drawn in. The amount of secondary air seems to
>be somewhat self regulating.

(Andrew)Yes this is much the same as Alex was suggesting and is quite
encouraging in simplifying things.

>(RWL): Actually, there is some advantage to drawing some of the required
>secondary air from the bottom. This can be done using some (all?) of your
>exterior chimney pipes - stacked vertically just like a piece of wood
>(using rocks or something to ensure they are not blocked) . These will
>draw secondary air from the bottom up past the pyrolysis zone and allow
>flame holding on these chimney pipe rims - at the upper level of the wood.
>There will not be a big draft here because this secondary air does not get
>very hot.

(Andrew)Well this is an easy enough modification, secondary air could be
controlled by the size and frequency of pipes embedded in the cordwood
>

>(RWL): I gather the flame was only at the top of these chimneys, with no
>lower secondary air?. Were these the 100 mm or the 150 mm dia? I believe
>that the main issuwe is flame holding. Does anyone know how gas flaring
>works at refineries? They must have some good means of flame holding.

(Andrew)Correct, 150mm chimneys
>
> If you could introduce secondary air at the bottom of these present
>chimneys, you might have a better flame (inside rather that outside the
>chimney). The draft will go way up.
(Andrew)Again this is an easy enough modification, Any idea on ratio of
holes to chimney? I guess wee would have to reduce the inlets to balance the
draft.

>
>(RWL): I'm surprised at this snuffing, but don't know enough about welding
>torch operation. I was thinking you would have had fairly low flow - what
>was the chimney height? Any other thoughts from anyone?

(Andrew)Chimney height 1.5m, flow feels moist, remember every mol of water
evapourated will expand to ocupy 22.4 litres at STP (correct me if I am
wrong and how many mols of H2O to a kg) and hence steam evolution will
contribute a lot to increasing flow. At low pressures and flow of
oxy-acetylene it is not difficult to blow off the flame, at higher rates it
will burn under water. I won't be able to experiment with this for a while,
all the oxy-acetylens kit (and my saws) were stolen yesterday, one of the
difficulties of working in an urban environment-:(
<snip>

>(RWL): I'm not sure whether the slits are in the outer pipe or the inner
>pipe. Can you describe where the pyrolysis gases and air are mixing and
>where first flaring and flame holding are occurring.
(Andrew)In the outer pipe, mixing just above the inner top, it was not
possible to see the flame , just its effect in reducing smoke, it must have
been somwhere in the short outer pipe.
>
>(Andrew):
> When the torch was applied the gas burned in the pipe
>>for 10secs after the torch was removed and the output became dramatically
>>smokeless. Towards the end of the day prior to shut down it became difficult
>>to light the stacks, though by then the smoke was minimal.
>
>(RWL): Was the extinguishment always attributable to the wind?
(Andrew)I do not think so as the outer pipe acts as a shield
AJH

From larcon at sni.net Sun Jul 13 00:54:57 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:28 2004
Subject: Re]: Flame holding (English)
Message-ID: <v01540b00afeddf37b7a4@[204.133.251.2]>

Alex said (following Re[3]: Top lit charcoal kiln (Heggie) of July 12)

>Summary: Flame Holding in an Oil Burner is done with a pilot light or
>through various obstructions and vanes which force the flame to
>circulate back into the middle of the flame.

<snip>

(Alex):
>Older pressurized oil burners used a continuous spark/arc across
>electrodes as a pilot light. More modern oil burners have dispensed
>with the spark (after start up) and use a cone shape, or flat disc
>in the case of our Riello burner, placed in the middle of the air
>flow which causes some back eddies.

(RWL): 1. If we think of the cone as a bullet - does the bullet point
with the gas flow or against it?

2. If the chimney is 150 MM, about what size cone or disk?

(Alex): >These obstructions usually have
>radial slits all opened in one direction to add swirl. With these
>burners, the flame appears to cling to the obstruction, hence their
>named 'flame retention heads'. In unrelated experiments, I have
>used these oil burner assemblies as ignition systems with high
>velocity air (roughly at 100mph), fully expecting
>the flame to be blown off, but it didn't happen.

(RWL): 1. Maybe 6-10 slits? (I've never seen one)

2. I presume that we are trying to get these as hot as possible
(lightweight supports)?

(Alex):
>I too would like to hear about petroleum industry flares. My guess is
>that they use high pressure which sets up a dynamic which negates
>the effects of wind. Balloonists have a novel approach, they operate
>as part of the wind. Can you picture large floating pyrolysis piles?

(RWL): Wow! Before pressurized propane, this might have been a pretty good
way.

(Alex):
>However with your low pressure needs you may wish to try and complete
>combustion in the pipe, perhaps in a widened section. Then in an
>additional section of chimney you could install a barometric draft
>controller. This is standard equiptment on household oil furnaces,
>used to prevent excess draft effects on the furnace. They are simple
>and cheap and could even be home made.

(RWL): Alex - 1) please describe a "barometric draft controller."

2) In your conical approach - I believe you had secondary and tertiary air
- with flame both in the cone and outside - something like Andrew's. Any
trouble with flame extinguishment and smoke under windy conditions?
>

(Alex)"
>I think that flaring at a single point might be something worth
>considering. Investing in a single larger flame may offer some
>stability.
>Good luck, I might start to play here.
>After the hay is in. Alex

Great - see note today to Andrew on the need for studies on moisture
content (and probably lots of other things). Are you thinking of balloon
travel?

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Sun Jul 13 00:54:59 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:28 2004
Subject: Top-lit charcoal kiln (Heggie)
Message-ID: <v01540b01afedeb549047@[204.133.251.2]>

>>>Summary: {Continued on] proposed testing of a top-lit large charcoal kiln
>and partial success with flaring existing chimneys
>
<snip>

(RWL):
>> If you could introduce secondary air at the bottom of these present
>>chimneys, you might have a better flame (inside rather that outside the
>>chimney). The draft will go way up.

>(Andrew)Again this is an easy enough modification, Any idea on ratio of
>holes to chimney? I guess we would have to reduce the inlets to balance the
>draft.
>
(RWL): Maybe (at first) a slit would be best with an ability to change
its height. Maybe a couple of 1 cm rods (maybe with a flame holder of the
type described by Alex today) across the lower "nipple" (that could be
changed to other sizes). Then the upper chimney needs to be placed above
the flame holder - and be well braced.

2) Another way to decrease the draft is to reduce the chimney
height. If you have been using 2 or 3 lengths, maybe 1 will be enough.

(Andrew): <snip> I won't be able to experiment with this for a while,
>all the oxy-acetylens kit (and my saws) were stolen yesterday, one of the
>difficulties of working in an urban environment-:(

(RWL): Many sympathies - I had thought we were the only ones so inflicted.

>>(RWL): I'm not sure whether the slits are in the outer pipe or the inner
>>pipe. Can you describe where the pyrolysis gases and air are mixing and
>>where first flaring and flame holding are occurring.

>(Andrew)In the outer pipe, mixing just above the inner top, it was not
>possible to see the flame , just its effect in reducing smoke, it must have
>been somwhere in the short outer pipe.

(RWL): With this double pipe - gas can enter both of them at the bottom level?

<snip>

>>(RWL): Was the extinguishment always attributable to the wind?

>(Andrew)I do not think so as the outer pipe acts as a shield

(RWL): See comments today from Alex - on flame holding. Even with a
shield, there may be enough pressure fluctuation to cause flame separation
and loss.

Summary - The issue here is the applicability of top-lighting in
general, but especially under wet fuel conditions. With bottom lighting,
this wet wood can be eventually pyrolyzed, but there is a lengthy period
when too much moisture and CO2 are present and flaring is not possible.

With very wet wood with top lighting, there are only three
possibilities

a) everything goes well.

b) you can't get it to pyrolyze at any level of primary air input
(but I think it is probably better to operate at a high air - high power -
level)

c) it pyrolyzes, but the high moisture content of the output
precludes igniting the pyrolysis gases.

I haven't tried this test, but think those who have some
charcoal-making stove capability might see how high we can get in moisture
content - for Andrew's sake. Can anyone (like David Beattie) add anything
theoretical? Note Case c) offers the possibility of perhaps condensing
some of the moisture out and then flaring the remainder. But that will
require a fan and gets us out of the backyard category. Alternatively in
Case c, we might add some extra gas. I don't see any hope in case b
(except pre-drying).

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From elk at arcc.or.ke Sun Jul 13 01:41:16 1997
From: elk at arcc.or.ke (Elsen L. Karstad)
Date: Tue Aug 31 21:35:28 2004
Subject: Top-lit charcoal kiln (Heggie)...Flame Holding
Message-ID: <m0wnHPU-0006WpC@arcc.or.ke>

Andrew;

I've been running test after test at minumum 'turndown' on the 2can charcoal
making stove & feel that a 3/8 inch rebar placed horizontally accross
(within)the hottest part of the combustion chamber has a beneficial
'sparkplug' effect allowing primary air to be minimised after the unit has
reached normal operational temperatures. This is a cue taken from Paul
Haite's description of the pyromid's operation (any patent infringements
there Paul?).

Wind is your enemy. Flame holding on a gusty day is difficult at the best of
times unles you're running at nearly full power. Some sort of effective wind
shield is needed.

Dry wood is so much more manageable- I like Ronal's suggestion that green
wood could be stacked over operating kilns to at least partially dry.
Commercial logistics & the cost of labour on your side of the globe may
trash that idea though.....

What was the final % yield of charcoal? Any different from the norm for your
operation?

Keep up the good work if you can- this may have applications here too.

elk

From ahe1 at cableol.co.uk Sun Jul 13 05:52:34 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:28 2004
Subject: combustion space chimneys
Message-ID: <9707130953.AA07085@mars.cableol.net>

>Summary: Necessary chimney height inversely proportional to
>density ( ie: temperature) of gasses.
Alex+stovers
I have changed the thread title as it appears there is common ground in
developing a chimney/combustion space which will burn the low calorific
value pyrolysis gases which occur at startup and end of burning these batch
loaded devices.

(Ronal): I hope others like Tom, Elsen, and Alex can correct or add
to these
>> >comments. The things I would worry about most are getting a good draft
>> >(enough height) and finding ways to be flexible in the chimney height and
>> >width of the secondary air slit.
(Andrew): Conventional stove chimneys are stackable in 1m lengths, for this
purpose I
>> will use spiral ducting and from what you say will expect it to burn out.
>> AJH
>
(Alex):The more you develop a well mixed and contained flame within the
>chimney, which could now be called a combustion chamber, the shorter
>the chimney will need to be. This can be an accelerating process up
>to the flow limits of the chimney, as in a creosote chimney fire.
>The problem is that this is not the "startup" condition, indeed you
>have a constantly changing condition during your long process.

(Andrew):I wonder if such a chimney could be made constant draft by
entraining/bleeding in excess air to maintain the density of the flow of
gasses in the chimney, as long as this did not quench the flame it may be
controllable by a simple bimetal strip acting remotely via a rod on a simple
cap below the chimney.
(Alex)The venturi arrangement that I have used seems to have a built in (
>but not by design) regulatory effect on the draft below the venturi.
>As the flame intensity and draft increases above the venturi, the
>more the venturi draws secondary air into its mid section squeezing
>the throat diameter and the potential draft below the venturi.
>Someone needs to try this on a larger scale than I have. Andrew?

(Andrew):I have limited ability in this field, if the initial trials improve
the simple flaring then I will be able to play more as there would be a
number of existing ring kilns which might benefit.

The self regulation feature is similar to that which I understand of
downdraft gasifiers running ic engines. The higher the demand from the
engine the more primary air drawn in, this increases the depth of
incandescent charcoal in the gasification portion of the primary combuster,
adds heat which increases the pyrolysis zone and hence evolves more fuel gas.
>
>This is, of course, all conjecture. I probably don't need to say this,
>as sure as you recognize my signature.
(Andrew):As is mine at present.

At 08:32 12/07/97 -0500, Alex wrote:

>Summary: Flame Holding in an Oil Burner is done with a pilot light or
>through various obstructions and vanes which force the flame to
>circulate back into the middle of the flame.

(Andrew): Are we likely to achieve sufficient velocity to achieve this in
the absence of fans, small fans would not be a problem in my situation but
would not be appropriate for a small domestic stove.

> More modern oil burners have dispensed
>with the spark (after start up) and use a cone shape, or flat disc
>in the case of our Riello burner, placed in the middle of the air
>flow which causes some back eddies. These obstructions usually have
>radial slits all opened in one direction to add swirl.

(Andrew):Again this appears a simple modification to a current chimney but
how much would the chimney need to be increased in length to maintain draft?
Would one increase diameter of the chimney at the flame retaining head to
maintain a constant cross section?

>However with your low pressure needs you may wish to try and complete
>combustion in the pipe, perhaps in a widened section. Then in an
>additional section of chimney you could install a barometric draft
>controller. This is standard equiptment on household oil furnaces,
>used to prevent excess draft effects on the furnace. They are simple
>and cheap and could even be home made.

(Andrew):Well we seem to have at least three possible improvements that
could be made to acheive combustion in a chimney space:
Two possible ways of draft control and a flame retention idea, with a
ceramic chimney to prevent heat loss from the flame by radiation, it might
be possible to burn down to a low cv of the pyrolysis gas.
>
>I think that flaring at a single point might be something worth
>considering. Investing in a single larger flame may offer some
>stability.

(Andrew):If the top lighting works this will happen as only one chimney is
proposed.

(Ronal wrote on 11/07/97):Control the secondary air slit to get the right amount
of excess air (if you could measure CO2 - I gather that 10-12 % each of O2
and CO2 are considered acceptable).

(Andrew):If the figure of 10-12% excess air and 10% CO2 holds true for most
situations could a simple device for manual control of the stove be made
with a display which only indicated high, optimum and low for both gases and
ignoring CO after developement?
AJH

From ahe1 at cableol.co.uk Sun Jul 13 07:15:07 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:28 2004
Subject: Top-lit charcoal kiln (Heggie)...Flame Holding
Message-ID: <9707131115.AA13185@mars.cableol.net>

At 08:41 13/07/97 EAT, Elsen wrote:

>I've been running test after test at minumum 'turndown' on the 2can charcoal
>making stove & feel that a 3/8 inch rebar placed horizontally accross
>(within)the hottest part of the combustion chamber has a beneficial
>'sparkplug' effect allowing primary air to be minimised after the unit has
>reached normal operational temperatures. This is a cue taken from Paul
>Haite's description of the pyromid's operation (any patent infringements
>there Paul?).

(Andrew): Again a worthwile trial, similar to the glow plug used in early ic
engines.
>
>Wind is your enemy.

(Andrew):Noted, I shall have to re-read all this correspondence to make sure
I can assimilate this into an intelligent system.
>
>Dry wood is so much more manageable- I like Ronal's suggestion that green
>wood could be stacked over operating kilns to at least partially dry.
>Commercial logistics & the cost of labour on your side of the globe may
>trash that idea though.....

(Andrew):Actually rehandling wood with our commercial forestry equipment is
fairly cheap. Space and safety considerations are the problem.

I, in fact, feel not to use dry wood is a big mistake, essentially using
natural air drying is such a "green" means of enhancing the calorific value
and making use of solar power with no capital cost, albeit some loss of cash
flow, that if my experiment fails it should not reflect on the general concept.
>
>What was the final % yield of charcoal? Any different from the norm for your
>operation?

(Andrew):We have not unloaded our last burn yet so have not tried the top
lighting, just attempted to flare the existing chimneys. I anticipate a
delay also whilst I regroup my tools and make the necessary modifications.
>
>Keep up the good work if you can- this may have applications here too.

(Andrew):Thanks, as you may see in my post of this morning I too feel we
have common aims, a difference mainly in scale.
AJH

From ahe1 at cableol.co.uk Sun Jul 13 07:15:23 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:28 2004
Subject: Top-lit charcoal kiln (Heggie)
Message-ID: <9707131115.AA01714@mars.cableol.net>

At 22:56 12/07/97 -0600, you wrote:
>>>>Summary: {Continued on] proposed testing of a top-lit large charcoal kiln
>>and partial success with flaring existing chimneys

>(RWL): With this double pipe - gas can enter both of them at the bottom
level?
(Andrew): No, the pipe was a sacrificial piece to experiment with, it was
just a convenient size to sleeve over the chimney, which I did not wish to
modify, air could only enter through the slit the working length of which
could be varied by moving the outer sleeve/pipe up or down.

Next time I shall attempt some photos as the change in smoke was quite
dramatic whist the flame held.
<snip>

>(RWL): See comments today from Alex - on flame holding. Even with a
>shield, there may be enough pressure fluctuation to cause flame separation
>and loss.

(Andrew):Noted, so I may well be wrong!

> Summary - The issue here is the applicability of top-lighting in
>general, but especially under wet fuel conditions. With bottom lighting,
>this wet wood can be eventually pyrolyzed, but there is a lengthy period
>when too much moisture and CO2 are present and flaring is not possible.
>
> With very wet wood with top lighting, there are only three
>possibilities
>
> a) everything goes well.
>
> b) you can't get it to pyrolyze at any level of primary air input
>(but I think it is probably better to operate at a high air - high power -
>level)
>
> c) it pyrolyzes, but the high moisture content of the output
>precludes igniting the pyrolysis gases.
>
> I haven't tried this test, but think those who have some
>charcoal-making stove capability might see how high we can get in moisture
>content - for Andrew's sake. Can anyone (like David Beattie) add anything
>theoretical? Note Case c) offers the possibility of perhaps condensing
>some of the moisture out and then flaring the remainder. But that will
>require a fan and gets us out of the backyard category. Alternatively in
>Case c, we might add some extra gas. I don't see any hope in case b
>(except pre-drying).

(Andrew):I agree with your summary, but note also my reply today to Elsen.
There is no doubt in my mind we should not be practising our current method,
b and c scenarios would be avoided by any prudent culture. Condensing of
water generated by combustion of hydrocarbons is worthwhile, condensing of
moisture which has had a free ride through the system and contributed
nothing to the burn seems a poor approach and would present the problem of
disposal of large amounts of contaminated water. With this in mind I have
privately e-mailed David Beedie and hope for some collaboritive effort! I
feel even if a high tech system is developed the spin of for domestic
woodburning stoves may well be worthwhile.

I shall now study Mike Antal's paper which I have only skimmed through so
far, thanks Mike!
AJH

From REEDTB at compuserve.com Sun Jul 13 08:21:01 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:28 2004
Subject: Stove Characteristics (Heggie)
Message-ID: <199707130821_MC2-1AC8-334F@compuserve.com>

It would be nice if we could bring the secondary air up through the
pyrolysis zone to heat it for more efficient flaring as you suggest.
However, I don't think there will be very good heat transfer between the
pyrolysis zone at 500C and the uprising air. Furthermore, I believe it is
more difficult to mix the low density hot air with the volatile fuel gas
than high density cold air. However, give it a try if it is convenient.

Do you have any way of adding forced draft? That would make a good deal of
difference in the ease of secondary combustion.

How wet is your wood?

Good luck and let us know how it turns our, TOM REED

From REEDTB at compuserve.com Sun Jul 13 08:21:01 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:29 2004
Subject: Stove Characteristics (Heggie)
Message-ID: <199707130821_MC2-1AC8-3352@compuserve.com>

I don't understand residual char "kick starting" the next load. In my
experience, any fire at the bottom of the unit gobble up all the oxygen, so
none can arrive at the top and you then have an updraft gasifier.

TOM REED

From ahe1 at cableol.co.uk Sun Jul 13 16:21:27 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:29 2004
Subject: Stove Characteristics (Heggie)
Message-ID: <9707132021.AA10721@mars.cableol.net>

Andrew Heggie in reply to Tom Reed
>AJH and Ron:
>
>I don't understand residual char "kick starting" the next load. In my
>experience, any fire at the bottom of the unit gobble up all the oxygen, so
>none can arrive at the top and you then have an updraft gasifier.
Tom
I have answered your earlier post about moisture content earlier today and
am intrigued by the suggestion that high density cold air may achieve better
mixing with the hot low density fuel gases.

I think the residual char "kick starting" the next load was David Beedie
referencing his batch loaded gasifier, one reason for doing this appeared to
be the poor CO performance as the last of the char burned out. Your second
point about preventing turning the device into an updraft gasifier was
anticipated by Ronal when he advised against using fines to light the device
as they would fall throught the charge and start a fire as you have described.

From english at adan.kingston.net Sun Jul 13 19:18:21 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:29 2004
Subject: Re]: Flame holding (English)
In-Reply-To: <v01540b00afeddf37b7a4@[204.133.251.2]>
Message-ID: <199707132318.TAA18459@adan.kingston.net>

Dear Ron +
> (Alex):
> >Older pressurized oil burners used a continuous spark/arc across
> >electrodes as a pilot light. More modern oil burners have dispensed
> >with the spark (after start up) and use a cone shape, or flat disc
> >in the case of our Riello burner, placed in the middle of the air
> >flow which causes some back eddies.
>
> (RWL): 1. If we think of the cone as a bullet - does the bullet point
> with the gas flow or against it?

AE: Against it. The flame is entirely on the down stream side. Visit
your local "Plumbing/Heating and Refrigeration" supplier, they
usually have exposed floor models on display.

> 2. If the chimney is 150 MM, about what size cone or disk?

AE: The diameter of the cone may be up to 90% of the inside diameter
of the burner throat. I tried suspending a 2"(5cm) trailer hitch
ball in 4"(10cm) combustion chamber/chimney of the venturi burner,
with fairly good results. There is a picture of this " bluff body" on
the Web page.
>
> (Alex): >These obstructions usually have
> >radial slits all opened in one direction to add swirl. With these
> >burners, the flame appears to cling to the obstruction, hence their
> >named 'flame retention heads'. In unrelated experiments, I have
> >used these oil burner assemblies as ignition systems with high
> >velocity air (roughly at 100mph), fully expecting
> >the flame to be blown off, but it didn't happen.
>
> (RWL): 1. Maybe 6-10 slits? (I've never seen one)
AE: About that, the household furnaces have mere slits around the
outside of the cone as well.
>
> 2. I presume that we are trying to get these as hot as possible
> (lightweight supports)?
>
> (Alex):
> >I too would like to hear about petroleum industry flares. My guess is
> >that they use high pressure which sets up a dynamic which negates
> >the effects of wind. Balloonists have a novel approach, they operate
> >as part of the wind. Can you picture large floating pyrolysis piles?
>
> (RWL): Wow! Before pressurized propane, this might have been a pretty good
> way.
AE: That's two "wows" in two days. If someone ever does come up with
"the" stove to meet the needs of the worlds cooks it might be called
The WOW Stove, The World's Optimized Wood Stove.
>
> (Alex):
> >However with your low pressure needs you may wish to try and complete
> >combustion in the pipe, perhaps in a widened section. Then in an
> >additional section of chimney you could install a barometric draft
> >controller. This is standard equiptment on household oil furnaces,
> >used to prevent excess draft effects on the furnace. They are simple
> >and cheap and could even be home made.
>
> (RWL): Alex - 1) please describe a "barometric draft controller."
AE: Again visit your local......
It is an adjustable balanced flap in tee branch of the chimney which
allows house air to be sucked up chimney when the negative draft
pressure exceeds that for which it has been adjusted, thus maintaining
the draft in the combustion chamber of the furnace within an optimum
range for a stable clean flame. I gather, after reading an article by
Skip Hayden, that the barometric draft controller can be a major
factor in reducing the overall efficiency of home heating with oil
furnaces.
>
> 2) In your conical approach - I believe you had secondary and tertiary air
> - with flame both in the cone and outside - something like Andrew's. Any
> trouble with flame extinguishment and smoke under windy conditions?
AE: I have not had the wind extinguish the flame. Likely because of
the strong "pilot light" coming from the fuel itself fully
combusting. The wind does certainly affect the flame stability and
emissions, including producing a puff of smoke.
> >
>
> (Alex)"
> >I think that flaring at a single point might be something worth
> >considering. Investing in a single larger flame may offer some
> >stability.
> >Good luck, I might start to play here.
> >After the hay is in. Alex
>
>
> Great - see note today to Andrew on the need for studies on moisture
> content (and probably lots of other things). Are you thinking of balloon
> travel?
AE: It would be interesting to send a venturi burner aloft, but no I
would be interested in trying some larger scale, green wood, flared,
charcoal making. We have the necessary raw materials around here.

Alex
>
> Regards Ron
>
> Ronal W. Larson, PhD
> 21547 Mountsfield Dr.
> Golden, CO 80401, USA
> 303/526-9629; FAX same with warning
>
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Sun Jul 13 22:38:09 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:29 2004
Subject: combustion space chimneys
In-Reply-To: <9707130953.AA07085@mars.cableol.net>
Message-ID: <199707140238.WAA24669@adan.kingston.net>

Dear Andrew +

> (Andrew):I wonder if such a chimney could be made constant draft by
> entraining/bleeding in excess air to maintain the density of the flow of
> gasses in the chimney, as long as this did not quench the flame it may be
> controllable by a simple bimetal strip acting remotely via a rod on a simple
> cap below the chimney.

AE: I don't think you want to alter your mix. The other variables are
chimney height and resistance. If you attach your rod to a bluff
body so as to lower it in a conically shaped combustion chamber
section then you can have a stabilized flame and damper built into
one. Alternatively, a primary air intake whose flow curve flattens
at higher draft pressures might work, although I don't know what it
would look like for these thermal drafts.

Alex
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From larcon at sni.net Sun Jul 13 23:49:22 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:29 2004
Subject: Flame holding (English)
Message-ID: <v01540b04afef4b3f5920@[204.133.251.3]>

Summary - A few questions on oil/gas heater references.

Today, Alex said:

>AE: <snip> I gather, after reading an article by
>Skip Hayden, that the barometric draft controller can be a major
>factor in reducing the overall efficiency of home heating with oil
>furnaces.

(RWL): I feel a need to read more about topics like this. Could you and
Skip reference this and other similar papers on flame holding, etc, Are
there text books (or better handbooks) on how these design problems are
solved?

Is this so small an issue (or such a trade secret) that no-one
writes about the theory and experimental verification?

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Sun Jul 13 23:50:04 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:29 2004
Subject: CO production and quenching (English)
Message-ID: <v01540b05afef4db4ecd8@[204.133.251.3]>

Summary: A followup to Alex on reasons for high CO.

Alex said today in a reply to Tom Reed relative to CO production:

>AE: <snip>
> It is possible, even likely, that gasses had not completely
>finished burning at the sample point, which would result in a higher
>reading.

(RWL): I think this "quenching observation" is a great point. We have to
try for stove designs and stove education that minimize this problem. We
might recognize its occurence by measuring CO at various power levels. At
lower powers the combustion should always be more complete at a given
height.

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Sun Jul 13 23:50:12 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:29 2004
Subject: combustion space chimneys
Message-ID: <v01540b02afef4530ecaf@[204.133.251.3]>

Summary: comment on avoiding changing chimney height.

Andrew today said (responding to Alex):
>
>(Andrew):I wonder if such a chimney could be made constant draft by
>entraining/bleeding in excess air to maintain the density of the flow of
>gasses in the chimney, as long as this did not quench the flame it may be
>controllable by a simple bimetal strip acting remotely via a rod on a simple
>cap below the chimney.

<snip>

>The self regulation feature is similar to that which I understand of
>downdraft gasifiers running ic engines. The higher the demand from the
>engine the more primary air drawn in, ... <snip>

1. I think you will find that the draft is amazingly constant over
time (and you won't care very much anyway if it isn't).

2. I think the easiest way to control the draft will be with the
primary air control - as suggested in your second paragraph - shoveling a
little sand. (I presume that engine control has the equivalent of moving
sand)

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Sun Jul 13 23:50:06 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:29 2004
Subject: Top-lit charcoal kiln (Heggie)...Flame Holding
Message-ID: <v01540b01afef42d85f87@[204.133.251.3]>

Summary: Some questions on Elsen's flame holding with rebar.

Elsen said today as a suggestion to Andrew::

(RWL): 1. What was the length of this rebar and how attached?

2. At what height above the secondary air supply slit?

3. Could you see the bar and what colr?

4. Still an FOM of 1? (I think the dryness of the wood will have a big
effect on this measure)

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From larcon at sni.net Sun Jul 13 23:50:18 1997
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:35:29 2004
Subject: Top-lit charcoal kiln (Heggie)
Message-ID: <v01540b03afef47c587d1@[204.133.251.3]>

Summary: {Continued on] proposed testing of a top-lit large charcoal kiln
and partial success with flaring existing chimneys

Today, Andrew said in a reply:
>
>(Andrew):I agree with your summary, but note also my reply today to Elsen.
>There is no doubt in my mind we should not be practising our current method,
>b and c scenarios would be avoided by any prudent culture. Condensing of
>water generated by combustion of hydrocarbons is worthwhile, condensing of
>moisture which has had a free ride through the system and contributed
>nothing to the burn seems a poor approach and would present the problem of
>disposal of large amounts of contaminated water.

(RWL): I don't want to get very deeply into this (especially because I
know nothing about it), but I gather that you will condense a lot of
material besides water - some of which may be fairly valuable. You might
well be able to sell barrels of this "water".

>With this in mind I have
>privately e-mailed David Beedie and hope for some collaboritive effort! I
>feel even if a high tech system is developed the spin of for domestic
>woodburning stoves may well be worthwhile.

(RWL): I hope that David and you will also keep us informed of anything
not too proprietary.

Regards Ron

Ronal W. Larson, PhD
21547 Mountsfield Dr.
Golden, CO 80401, USA
303/526-9629; FAX same with warning

From elk at arcc.or.ke Mon Jul 14 08:32:25 1997
From: elk at arcc.or.ke (E. L. Karstad)
Date: Tue Aug 31 21:35:29 2004
Subject: 2can Trials
Message-ID: <v01510101afefc757f91a@[199.2.222.130]>

>Summary: Some questions on Elsen's flame holding with rebar.
>
>Elsen said today as a suggestion to Andrew::
>
>>I've been running test after test at minumum 'turndown' on the 2can charcoal
>>making stove & feel that a 3/8 inch rebar placed horizontally accross
>>(within)the hottest part of the combustion chamber has a beneficial
>>'sparkplug' effect allowing primary air to be minimised after the unit has
>>reached normal operational temperatures. <snip>
>
>(RWL): 1. What was the length of this rebar and how attached?
>
>2. At what height above the secondary air supply slit?
>
>3. Could you see the bar and what colr?
>
>4. Still an FOM of 1? (I think the dryness of the wood will have a big
>effect on this measure)

1) The rebar was simply wedged accross the combustion chamber in the zone I
determined to be the hottest.

2) About 10cm above secondary air slit.

3) It glows a dull red.

4) F.O.M.'s of between 1 and 1.15 are being achieved and burning times
stretching to over 2.5 hours with 7 to 7 kg wood. Turndown's good but
charcoal production's quite variable for some reason

I'm insulating the stove with refractory cement today & will provide a
synopsis of the trials to date together with the first two insulated trial
results.

Ron, I'm off on 3 weeks leave starting Wed. eve., if British Airways isn't
on strike, and I reckon that I should go off-list 'till 10/8/97. I'll catch
up from the archives on my return. I'm redirecting mail to a B.C. address,
so anything specific for me can be addressed privately & I'll get it during
this period.

All for now;

elk

_____________________________
Elsen Karstad
P.O Box 24371 Nairobi, Kenya
Tel:254 2 884437
E-mail: elk@arcc.or.ke
______________________________

From english at adan.kingston.net Mon Jul 14 12:33:22 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:29 2004
Subject: Flame holding (English)
In-Reply-To: <v01540b04afef4b3f5920@[204.133.251.3]>
Message-ID: <199707141634.MAA10832@adan.kingston.net>

Dear Ron +

Summary: Articles available on the web and well worth reading even
though they are not specifically about cooking stoves.
>
> >AE: <snip> I gather, after reading an article by
> >Skip Hayden, that the barometric draft controller can be a major
> >factor in reducing the overall efficiency of home heating with oil
> >furnaces.
>
> (RWL): I feel a need to read more about topics like this. Could you and
> Skip reference this and other similar papers on flame holding, etc, Are
> there text books (or better handbooks) on how these design problems are
> solved?
The following reference excellent articles about wood combustion.
Skip's article, a reprint from Home Energy Magazine, can be found at
http://hearth.com/what/more/skip.html.
Another equally interesting article by Paul Tiegs of Omni
Enviornmental Services can be found at
http://mha-net.clever.net/html/p-tieg02.htm
For folks who do not have web access I could attach the text to an
email and send it directly.

Alex
> Is this so small an issue (or such a trade secret) that no-one
> writes about the theory and experimental verification?
>
> Regards Ron
>
> Ronal W. Larson, PhD
> 21547 Mountsfield Dr.
> Golden, CO 80401, USA
> 303/526-9629; FAX same with warning
>
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Mon Jul 14 12:33:20 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:29 2004
Subject: CO production and quenching (English)
In-Reply-To: <v01540b05afef4db4ecd8@[204.133.251.3]>
Message-ID: <199707141634.MAA10829@adan.kingston.net>

Dear Ron +
Summary: "Low power" has higher CO in venturi burner.
> Alex said today in a reply to Tom Reed relative to CO production:
>
> >AE: <snip>
> > It is possible, even likely, that gasses had not completely
> >finished burning at the sample point, which would result in a higher
> >reading.
AE: This was referring primarily to the fact that I was sampling to
close to the box stove (during the "rick" burn) in the stovepipe
chimney. There was still flame present in the gasses at this point in
the stove pipe during the peak of that burn. However that
corresponded to the lowest CO readings. It is true that
the stovepipe has a quenching effect.
>
> (RWL): I think this "quenching observation" is a great point. We have to
> try for stove designs and stove education that minimize this problem. We
> might recognize its occurence by measuring CO at various power levels. At
> lower powers the combustion should always be more complete at a given
> height.
AE: With the current venturi burner, mixing/turbulence and
temperatures are only optimal for low CO at the higher burn rates.
I think that optimization for a range of output levels requires the
simultaneous adjustment of primary and secondary air flow rates
while retaining gas velocities and mixing geometry, in and above the
venturi. The only solution I have imagined is probably to complex
to be useful in the kitchen context.

Alex
> Regards Ron
>
> Ronal W. Larson, PhD
> 21547 Mountsfield Dr.
> Golden, CO 80401, USA
> 303/526-9629; FAX same with warning
>
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From BeedieD at Cardiff.ac.uk Mon Jul 14 13:11:26 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:29 2004
Subject: message identification signatures
Message-ID: <3F497753B74@nrd1s.cf.ac.uk>

Initials Conversion Table:
DB: D Beedie
AJH: A Heggie
TBR: T Reed

Tom,
I take your point regarding identification. I guess you figure if
you complain at enough of us for long enough the message will get
through right? But did you read to the end of my message ? - you
would have found full contact details for yours truly (DB)! I
confess I had snipped out the previous respondent's full name so his
identity was obscured (restored above).

I have implemented your idea of an initial conversion table, above.
Is this what you had in mind ? This would make it easier to follow a
multi-party conversation - provided everybody follows the rules and
adds their own entry to their list.

By the way my contact detail paragraph appears at the end of my
messages because that's where my mail program puts the author's
'signature' details - unfortunately this cannot be changed. It's
fairly standard I believe.

Over.
Dave.

> Date sent: Fri, 11 Jul 1997 18:07:03 -0400
> From: Thomas Reed <REEDTB@compuserve.com>
> Subject: CV of gases evolved during charcoal kiln steaming phase
> To: David Beedie <BeedieD@cardiff.ac.uk>

> Thomas B. Reed 303 278 0558 V Colorado School of Mines
> 1810 Smith Rd., 303 278 0560 FX Department Chem Eng
> Golden, CO 80401 ReedTB@Compuserve.com
> ALSO: The Biomass Energy (non-profit)Foundation
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dear Stove-Charcoalers:
>
> 1) Please identify yourselves at least once in each letter with more than
> just initials. This STOVE node is bursting with great ideas and
> contributions, but it is sometimes difficult to follow the thread without
> an initial conversion table. Typing is cheap. I know I would like to
> think that everyone knows TBR, but to be on the safe side, I use TOM REED.
>
> 2) If I understand the discussion below, CV is the energy content of the
> stack gas on a weight basis - ie Db says gas must be at least 1.0 Mj/kg to
> burn in a low CV burner. For those on other systems, 1 kg of gas is about
> 1 m3, so gasification people would call this a 1 Mj/m3 gas instead. For
> reference, low energy (producer) gas is typically 5-6, medium energy 10-15
> and high (methane) 30.
>
> 3) I presume that in the second stage of bottom heated charcoal making the
> pyrolysis gases are at least medium energy (10-15 MJ /m3), but in stage 1
> they range from 0 at the beginning through 1 (difficult to burn) to 10,
> easy to burn.
>
> 4) One advantage to top down charcoal making is that the moisture is
> evaporated concurrently with the pyrolysis products, so that a moderately
> dry wood will give 8-15 MJ /m3.
>
> 5) Has anyone tried top down charcoal manufacture on a large scale with
> moderately dry wood (<20% MC , WB)?
>
> 6) Wouldn't it be amazing if top lighting could make high yield charcoal
> and a combustible gas and that it hasn't been discovered yet after 10,000
> years of charcoal burning?
>
> Who'll try it first?
>
> Truly, TOM REED
>
> >DB:
> > >Regarding the following excerpt I've snipped from your recent
> > >posting, can you suggest a figure for the CV of the gases evolved from
> > >a charcoal kiln during the early (steaming) part of the cycle? [Net
> > >CV (i.e. assuming combustion product moisture is in gaseous form) is
> > >probably the most useful measure.]
> > >?
> AJH
> > I have not any way of measuring this, actually (as you infer)as it
> contains
> > visible water vapour there would be some energy consumed in turning these
> > droplets to steam at approximately 2.7-2.9 mJ/kg depending on the flue
> > temperature. At this stage wood is being burned to drive off moisture in
> the
> > charge, that is why Ronal suggested it is highly polluting as its CV is
> not
> > high enough to sustain flaring because of dilution of any pyrolysis
> gasses
> > by combustion products, steam amd free water droplets. This is why I
> > suggested using bone dry wood, obviously not practical in the field and
> then
> > we could calculate input CV of wood at 18.6 mJ/kg less output CV of
> charcoal
> > at 30mJ/kg the differences would be in 1)heat loss from system,
> 2)sensible
> > heat of charcoal 3)sensible heat of gasses 4)CV of gases. For instance if
> > 1kg of wood reduced to .25kg of charcoal then energy difference is
> 11.1mJ.
> > If the kiln temperature was 300c then we would know .75kg of gases and
> .25kg
> > of charcoal at 300C at their respective specific heats were accounted
> for.
> > The balance should be in the losses from the vessel ( I wish to move away
> > from kilns, too much black art involved), which could be minimised with
> > insulation, and chemical energy of the gases, or am I being too
> simplistic.
> > Not everyday calculations for a woodman!
> > AJH
>
> DB:
> Not everyday calculations for anyone else either I would guess.
> This approach would also produce a value averaged over the cycle.
> I am specifically interested in the CV of the 'steaming' gases -
> although they will not sustain flaring owing to the high proportion of
> evaporated moisture and combustion products, they may nevertheless
> possibly have enough energy to sustain combustion in a good low-CV
> burner. Has anyone tried this ? Low-CV burners have improved.
>
> This is clearly not a natural draught proposition - a fan is needed
> for the burner - but it would be a way of getting a clean process
> without support fuel - if the gases have a net CV above about 1MJ/kg.
>
> The forced draught for the burner could be arranged to induce a
> draught in the kiln which I surmise might give additional advantage
> control-wise.
> **********************************************
> ** **
> ** Note temporary home telephone number !! **
> ** **
> **********************************************
> (Dr) David Beedie
> School of Engineering, University of Wales, Cardiff, UK
>
> email: BeedieD@cardiff
>
> Office Tel. 01222 874683; 874000 ext.5927(lab.)
> Office FAX: 01222 874420 - mark for my attention !
> Home tel: 481424 (temporary number ...)
> *******************************************************
> <
>
>**********************************************
** **
** Note temporary home telephone number !! **
** **
**********************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From BeedieD at Cardiff.ac.uk Mon Jul 14 14:18:46 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:29 2004
Subject: correlation of CO with other pollutants
Message-ID: <3F5B5BE57E1@nrd1s.cf.ac.uk>

Alex,
A relevant name comes to mind - papers have appeared by Hubbard in
1990s conferences - I don't have the references handy. If you can't
easily do an abstract search I'll hunt them out...
I believe many correlations were fairly equipment-specific but some
general ones held.

> AE: It may be that the largest share of health problems related to
> stoves is due to the particulates, PAH's and VOC's. (Poly aromatic
> hydrocarbons and volatile organic compounds) I am just as
> interested in knowing what the comparative levels are of those are,
> but am not about to run off and buy the necessary equiptment to find
> out. There are other quieter folks doing that. I would be equally
> interested in knowing if there is any clear established relationship
> between the co-factors of time/temperature/turbulence and non-fly ash
> particulates, PAH's and VOC's. The EPA in the US is seems more
> focussed on these, as compared with CO emissions.. For the
> combustion of wood gasses, is a CO/CO2 of .001 or less accompanied by
> low levels of these other toxins ?
> Alex English
> RR 2 Odessa Ontario
> Canada K0H 2H0
> 613-386-1927
> Stoves Web Site http://www1.kingston.net/~english/Stoves.html
**********************************************
** **
** Note temporary home telephone number !! **
** **
**********************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From REEDTB at compuserve.com Mon Jul 14 18:48:58 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:29 2004
Subject: Top-lit moisture research
Message-ID: <199707141848_MC2-1AE0-2708@compuserve.com>

The question of moisture in the top down charcoal experiment is all
important. As the top layer is ignited, it must dry and ignite the next
lower layer for the reaction to proceed. It that lower layer is 50%
moisture there is no way it can continue. 20% maybe. 10% certainly. I
reported on the dynamics of propogation in 1984 for forced convection
gasifiers, but would love to study it for natural convection.

I have long planned a study on the effect of moisture in the small stoves.
A simple experiment:

1) Take a standard fuel - ie 1" square wood blocks

2) Oven dry them to 0% moisture (4 hr at 220F)

3) Place them in plastic bags with the necessary amount of moisture to
give 10%, 15%, 20%, 30% and wait a week or two for equilibrium to be
established (no visible water in bags)

4) Fill the stove with wet wood and one layer of dry wood on top for
starting

5) Start the stove and observe time of propogation and yield of charcoal.
I am sure that at a sufficiently high moisture content the fire will
extinguish.

Sounds easy? Sure, but if we keep answering all our E-mails, no one will
ever do it. (That's a challenge).

It is certainly easier to learn the dynamics of top down flaming pyrolysis
in a small stove than in piles of wood. But most people want to skip over
research and do the final project first. So we seldom learn much.

I also recognize that SOME research people only want to continue asking
more questions and never get to the useful part. NOT ME.

Keep up the great experiments, large and small.

Regards, TOM REED

From english at adan.kingston.net Mon Jul 14 21:51:08 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:29 2004
Subject: correlation of CO with other pollutants
In-Reply-To: <3F5B5BE57E1@nrd1s.cf.ac.uk>
Message-ID: <199707150151.VAA30652@adan.kingston.net>

Dear David

> Alex,
> A relevant name comes to mind - papers have appeared by Hubbard in
> 1990s conferences - I don't have the references handy. If you can't
> easily do an abstract search I'll hunt them out...

AE: I can't easily do an abstract search, but I am willing to drive
into Queens U. and try. I was just rereading the Paul Tiegs article,
referred to in an earlier email today. I think it speaks to this issue
of linking CO emissions to the other nasties. I would be interested
in your thoughts and others too.

Alex

> I believe many correlations were fairly equipment-specific but some
> general ones held.

> **********************************************
> ** **
> ** Note temporary home telephone number !! **
> ** **
> **********************************************
> (Dr) David Beedie
> School of Engineering, University of Wales, Cardiff, UK
>
> email: BeedieD@cardiff
>
> Office Tel. 01222 874683; 874000 ext.5927(lab.)
> Office FAX: 01222 874420 - mark for my attention !
> Home tel: 481424 (temporary number ...)
> *******************************************************
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From b.tremeer at mail1.remote.uva.nl Tue Jul 15 07:16:41 1997
From: b.tremeer at mail1.remote.uva.nl (Grant Ballard-Tremeer)
Date: Tue Aug 31 21:35:29 2004
Subject: Emission measurements
Message-ID: <199707151108.NAA07238@mail.uva.nl>

I haven't been able to keep up with all the discussions over the past month
or so, so forgive me if this has already been discussed... perhaps someone
could mail me a response directly if it has...

I'm concerned about how and where CO measurements are being made. Perhaps
these points are obvious:
1) is there adequate mixing of the combustion gases before they reach the
gas probe?
2) if there is any dilution of the gases from outside air, is it either
measured or known to be constant?
3) are measurements always being made the same distance from the fire?
4) since emissions frequently vary rapidly, are there enough readings to be
able to average them and make a little more sense of comparisons? I prefer
quoting emissions in grammes per task since this correlates well with
exposure (but one needs some fairly complex calibrated equipment for
this).
5) there are three (fairly simple) ways of measuring particulates for these
types of stove: my way: (using a light obscuration meter) gives 'real-time'
output, good for comparisons, but must be calibrated if more detail is
needed; Kirk Smith's way (using personnel monitors with filters) averages
over the burn cycle but requires a sensititive mass balance; and Jurgen
Usinger's way (of HEAT International, using a hand pump and filter spot)
gives a good visual indication of indoor pollution levels in the field.

Hope this helps
Grant

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Grant Ballard-Tremeer
International Institute for Energy Conservation - Europe (IIEC)
31 Pitfield Street, London N1 6HB UK, http://www.iiec.org
Tel: +44 171 490 7616 Fax: +44 171 490 7626
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
currently in South Africa:
Tel: +27 12 317 9283 Fax: +27 12 322 5224
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

From b.tremeer at mail1.remote.uva.nl Tue Jul 15 07:16:29 1997
From: b.tremeer at mail1.remote.uva.nl (Grant Ballard-Tremeer)
Date: Tue Aug 31 21:35:29 2004
Subject: correlation of CO with other pollutants
Message-ID: <199707151108.NAA07224@mail.uva.nl>

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Grant Ballard-Tremeer
International Institute for Energy Conservation - Europe (IIEC)
currently in South Africa: Tel: +27 12 317 9283 Fax: +27 12 322 5224
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I've done some detailed work on pollutant correlations... briefly put, I
found a poor correlation between CO and particulates for some cooking
devices (such as an open fire), and a good correlation for others (such as
a single pot metal stove). The reason appears to be related to the order
of magnitude of the burn rate variations compared to that of the
'internal'
variations between pollutants: The differences between CO and particulates
appeared to be obscured by the variations in emission rate caused by
changing burn rate. Some of these findings are published in "Biomass and
Bioenergy" Vol 11 No 5 pp 419-430, 1996 under the title 'Comparison of
Five Rural Wood-Burning Cooking Devices: efficiencies and emissions', by G.
Ballard-Tremeer and H.H. Jawurek.

Best wishes, Grant

----
From: *.English <english@adan.kingston.net>
To: stoves@crest.org
Date: 15 July 1997 03:50
Subject: Re: correlation of CO with other pollutants

>Dear David
>
>> Alex,
>> A relevant name comes to mind - papers have appeared by Hubbard in
>> 1990s conferences - I don't have the references handy. If you can't
>> easily do an abstract search I'll hunt them out...
>
>AE: I can't easily do an abstract search, but I am willing to drive
>into Queens U. and try. I was just rereading the Paul Tiegs article,
>referred to in an earlier email today. I think it speaks to this issue
>of linking CO emissions to the other nasties. I would be interested
>in your thoughts and others too.
>
>Alex
>
>> I believe many correlations were fairly equipment-specific but some
>> general ones held.
>
>> **********************************************
>> ** **
>> ** Note temporary home telephone number !! **
>> ** **
>> **********************************************
>> (Dr) David Beedie
>> School of Engineering, University of Wales, Cardiff, UK
>>
>> email: BeedieD@cardiff
>>
>> Office Tel. 01222 874683; 874000 ext.5927(lab.)
>> Office FAX: 01222 874420 - mark for my attention !
>> Home tel: 481424 (temporary number ...)
>> *******************************************************
>>
>>
>Alex English
>RR 2 Odessa Ontario
>Canada K0H 2H0
>613-386-1927
>Stoves Web Site http://www1.kingston.net/~english/Stoves.html
>

From REEDTB at compuserve.com Tue Jul 15 13:10:34 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:29 2004
Subject: CO production and quenching (English)
Message-ID: <199707151257_MC2-1AEA-33A@compuserve.com>

As I remember, the pots on my mother's (blue flame) stove sat about 2 cm
above the VISIBLE flame. I have always assumed that the VISIBLE edge of
the flame was where combustion reactions were completed. Does anyone have
information to the contrary?

TOM REED

From english at adan.kingston.net Tue Jul 15 22:18:11 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:29 2004
Subject: CO production and quenching (English)
In-Reply-To: <199707151257_MC2-1AEA-33A@compuserve.com>
Message-ID: <199707160218.WAA08330@adan.kingston.net>

Dear Tom +

> Hi:
> As I remember, the pots on my mother's (blue flame) stove sat about 2 cm
> above the VISIBLE flame.
AE: The flame on the stove at my folks cottage touches the pan when
it is turned up.
> I have always assumed that the VISIBLE edge of
> the flame was where combustion reactions were completed. Does anyone have
> information to the contrary?

AE: What is complete, zero CO ?

Help me design an experiment. I am thinking of using a small propane
torch with an insulated chimney, 5cm in diameter and 50cm tall. If
there is a declining CO reading at increasing distances above the
flame would this indicate that combustion is continuing past the
visible edge of the flame ?

Alex

>
> TOM REED
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From english at adan.kingston.net Tue Jul 15 22:18:41 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:29 2004
Subject: Emission measurements
In-Reply-To: <199707151108.NAA07238@mail.uva.nl>
Message-ID: <199707160218.WAA08325@adan.kingston.net>

Dear Grant
Summary: Alex 's response about the circumstances related to the
collecting of emissions data.

> I haven't been able to keep up with all the discussions over the past month
> or so, so forgive me if this has already been discussed... perhaps someone
> could mail me a response directly if it has...
>
> I'm concerned about how and where CO measurements are being made. Perhaps
> these points are obvious:
> 1) is there adequate mixing of the combustion gases before they reach the
> gas probe?
> 2) if there is any dilution of the gases from outside air, is it either
> measured or known to be constant?
> 3) are measurements always being made the same distance from the fire?
> 4) since emissions frequently vary rapidly, are there enough readings to be
> able to average them and make a little more sense of comparisons? I prefer
> quoting emissions in grammes per task since this correlates well with
> exposure (but one needs some fairly complex calibrated equipment for
> this).

AE: I think this is directed at the barrage of numbers I called
"psuedo data" that I sent to the list. I have been a bit scant on
details about my methods. In most cases I have tried to address these
issues that are listed above. It is difficult to know how well mixed
the gasses are that exit from a kerosene lamp, propane oven or other
appliances with high excess air factors. For the most part I have
approach this with the care of a oil furnace repairman as
opposed to that of scientist. So it is acceptable to add " a grain
of salt".

> 5) there are three (fairly simple) ways of measuring particulates for these
> types of stove: my way: (using a light obscuration meter) gives 'real-time'
> output, good for comparisons, but must be calibrated if more detail is
> needed; Kirk Smith's way (using personnel monitors with filters) averages
> over the burn cycle but requires a sensititive mass balance; and Jurgen
> Usinger's way (of HEAT International, using a hand pump and filter spot)
> gives a good visual indication of indoor pollution levels in the field.

Have these methods been cross referenced. The last one sounds like my
Bacharach smoke tester.

> Hope this helps

It does.......Alex
> Grant
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Grant Ballard-Tremeer
> International Institute for Energy Conservation - Europe (IIEC)
> 31 Pitfield Street, London N1 6HB UK, http://www.iiec.org
> Tel: +44 171 490 7616 Fax: +44 171 490 7626
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> currently in South Africa:
> Tel: +27 12 317 9283 Fax: +27 12 322 5224
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>
>
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From REEDTB at compuserve.com Wed Jul 16 11:04:31 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:29 2004
Subject: correlation of CO with other pollutants
Message-ID: <199707161104_MC2-1AFA-6429@compuserve.com>

Concerning correlation of CO with other pollutants, two extreme cases are
of interest:

1) I initially worried about CO in indoor cooking with the inverted
downdraft gasifier. However, I soon realized (cough, cough) that the high
levels of acrid tars that come with the CO offer the ideal warning. With
complete combustion inside the stove, no CO, no tars.

2) However, with charcoal combustion one can get high levels of CO with no
warning odorant.

TOM REED

From elk at arcc.or.ke Wed Jul 16 11:15:19 1997
From: elk at arcc.or.ke (Elsen L. Karstad)
Date: Tue Aug 31 21:35:29 2004
Subject: Exit insulated 2can & introducing 3can
Message-ID: <m0woVnl-0006bCC@arcc.or.ke>

In short, trials on the insulated 3can were not good.

Alex is right- get the secondary air too hot & efficiency goes down.
Significantly. The insulated 2can is a non-starter, and without insulation
we get an average FOM of 1.13 with 22% charcoal production. 2.5 hours burn
on 6 to 7 kg dry wood. It's a very nice stove to operate without the
isulation, just not efficient enough!

Back to the drawing board- I'll resume in mid August after my holidays with
the 3can charcoal making stove. I've got some staff putting one together
now & they'll be taking a few home to test under rigorous domestic
conditions while I'm away. Unfortunately I'm down to the wire on timing &
won't get to see the first burn, as I'm off on overseas leave as of today.

This stove is basic- no welding. Two 25kg paint cans vertically joined with
a fuel cell can (15 litre?) of a slightly smaller diameter attached to the
removable lid of the upside down lower can. Holes punched through both
bottom of lower can and lid allow for primary air to enter fuel cell can
from below only. This is controlled by sand or earth, as the stove rests
over a shallow depression. Horizontal triangular secondary air vents with
sliding valves are cut into the sides of the lower can- near the bottom,
allowing secondary air into the space between the outer and inner cans
(lower section). This secondary air will rise in the gap between fuel cell
can & the outer can, and preheat before encountering gas. Combustion will
take place around the edge and over the top of the fuel cell extending up
through the (removed) bottom of the top can into the top can itself.
Pyrolisis occurs in the fuel cell from top to bottom as usual.

Wew! bet you'll have to read this a couple of times... sorry!

So... the overall outside picture is of two 25 litre paint cans- the bottom
one is upside down and resting on it's lid over a shallow depression which
allows primary air to enter under the stove. This bottom can has had it's
bottom removed. The top 25 litre can is upright and attached to the lower
one. The top can also has it's bottom removed. These cans are slightly
tapered, so the stove will have a slight hourglass shape. There is no slit
to allow seconday air in at the junction. The cooking pot is inserted into
the top can through the top can's removable lid. Exhaust gas passes along
the sides of the cooking pot to escape.

A couple unique and hopefully effective features are:

-controllable secondary as well as primary venting.
-easily accessed materials (within Kenya, anyway)
-no welding necessary- a bit of riveting only
-preheating of secondary air as it passes up past pyrolisis in fuel cell
-the possibility of insulating the combustion chamber without overheating
secondary air
-reasonable wind shielding
-cheap - est USD 4.00 incl. labour.
-extinguish produced charcoal by separting the bottom of the stove (the
upside down lower can's lid) and placing an un-holed 25 l. paint can over
the fuel cell & onto the lid. Pile dirt around edge so no air can get into
primary vent holes.

Alex- care to give it a shot?

'Bye for now- I'll be back 12/8/97

elk

From BeedieD at Cardiff.ac.uk Wed Jul 16 12:02:15 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:29 2004
Subject: papers by Hubbard
Message-ID: <422E43375FA@nrd1s.cf.ac.uk>

Steven,
These are the references by AJ Hubbard I read:
Hubbard AJ. Hazardous air emissions potential from a wood-fired
furnace. In: Klass D, ed. Energy from Biomass and Wastes XVI.
Chicago: IGT, 1992;181-210.

Hubbard AJ, Fritz RA. Using upper and lower control limits to
regulate hazardous air emissions from wood-fired boilers. In:
Carvalho MG, ed. Third international conference on combustion
technologies for a clean environment, 3-6 July 1995. Vol II ed.
Lisbon: THERMIE, 1995;34.3,16-34.3,20.

> From: "Gust, Steven" <Steven.Gust@neste.com>
> To: "'BeedieD@Cardiff.ac.uk'" <BeedieD@cardiff.ac.uk>
> Subject: papers by Hubbard
> Date sent: Tue, 15 Jul 1997 13:21:14 +0300

> David
>
> I just did a search for paper sby Hubbard and came up with over 400
> different Hubbards. You wouldn't have a first name and initial would
> you?
>
> I am conducting combustion tests on pyrolysis liquids and am currently
> looking at particulates, PAHs and am doing AMES tests. It seems that the
> small scale combustion of wood can produce a lot of tars, PAHs,
> particulates and VOCs depending on type of stove and conditions.
>
> In the case of emissions, pyrolysis liquids produce significantly less.
> What I would like to do is get a good feeling of emissions from small
> stoves and fireplaces for comparison purposes and therefore the Hubbard
> or if you have another name might be a good place to start.
>
> Thanks for your help.
>
> Steven Gust
> Neste Oy, Finland
> tel +358 20 450 3738
> fax 6691
>**********************************************
** **
** Note temporary home telephone number !! **
** **
**********************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From BeedieD at Cardiff.ac.uk Wed Jul 16 12:14:36 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:29 2004
Subject: Top-lit charcoal kiln (Heggie)
Message-ID: <423515342B1@nrd1s.cf.ac.uk>

Andrew and Ron,

I'm responding to prompts in both your threads in Andrew's message -
see end!

> Date sent: Sun, 13 Jul 1997 12:15:54 +0100
> To: stoves@crest.org
> From: Andrew Heggie <ahe1@cableol.co.uk>
> Subject: Re: Re[4]: Top-lit charcoal kiln (Heggie)
> Send reply to: stoves@crest.org

(Ron L.:)
> > Summary - The issue here is the applicability of top-lighting in
> >general, but especially under wet fuel conditions. With bottom lighting,
> >this wet wood can be eventually pyrolyzed, but there is a lengthy period
> >when too much moisture and CO2 are present and flaring is not possible.
> >
> > With very wet wood with top lighting, there are only three
> >possibilities
> >
> > a) everything goes well.
> >
> > b) you can't get it to pyrolyze at any level of primary air input
> >(but I think it is probably better to operate at a high air - high power -
> >level)
> >
> > c) it pyrolyzes, but the high moisture content of the output
> >precludes igniting the pyrolysis gases.
> >
> > I haven't tried this test, but think those who have some
> >charcoal-making stove capability might see how high we can get in moisture
> >content - for Andrew's sake. Can anyone (like David Beattie) add anything
> >theoretical? Note Case c) offers the possibility of perhaps condensing
> >some of the moisture out and then flaring the remainder. But that will
> >require a fan and gets us out of the backyard category. Alternatively in
> >Case c, we might add some extra gas. I don't see any hope in case b
> >(except pre-drying).
>
> (Andrew):I agree with your summary, but note also my reply today to Elsen.
> There is no doubt in my mind we should not be practising our current method,
> b and c scenarios would be avoided by any prudent culture. Condensing of
> water generated by combustion of hydrocarbons is worthwhile, condensing of
> moisture which has had a free ride through the system and contributed
> nothing to the burn seems a poor approach and would present the problem of
> disposal of large amounts of contaminated water. With this in mind I have
> privately e-mailed David Beedie and hope for some collaboritive effort! I
> feel even if a high tech system is developed the spin of for domestic
> woodburning stoves may well be worthwhile.
>
> I shall now study Mike Antal's paper which I have only skimmed through so
> far, thanks Mike!
> AJH

To Ron,
A relevant piece of theory to the question: 'will the initial
pyrolysis products of charcoal-making (or whatever other process) be
combustible?' is the concept of adiabatic reaction temperature (ART)
(thoroughly described in Tom Reed's book on gasification). Tom,
excuse me... An exact temperature can be computed for the
combustion product mix of a fuel of known calorific value and
combustion stoichiometry, with certain conditions.
For our steamy gaseous 'fuel' gas, if we could estimate the moisture
content, and the CV and oxygen requirement of the remainder, we could
think about working out the ART. This might give a theoretical
indication of its combustibility.

To Andrew,
Re collaborative effort, keep in touch!
Re scenario c, there seem to be a few approaches: if the gases are
too wet to flare, they may be more amenable to combustion in
progressively more sophisticated combustion systems. If they are
just not burnable at all (without support fuel), drying the incoming
fuel must be worth looking at. If this doesn't help either then
condensing any of the moisture before trying to burn the gas could
make it burnable but presents the water disposal problem you point
out - and difficulties with tars etc in the condensing system. So
let's hope we can make burnable gas...

Dave B.**********************************************
** **
** Note temporary home telephone number !! **
** **
**********************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From BeedieD at Cardiff.ac.uk Wed Jul 16 12:39:33 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:29 2004
Subject: Stove Characteristics (Heggie)
Message-ID: <423BE620919@nrd1s.cf.ac.uk>

TBR Tom Reed
AJH Andrew Heggie
Ron Ron Larson

Tom,
Re your message at end, and as Andrew also has suggested, I suspect
you have wrongly attributed a comment of mine about my gasifier-
combustor to AJH and Ron.

The device was more cross-draught than updraught. The appropriate
time to reload was in the transition time as char combustion took
over from volatile combustion as the dominant process. The residual
char lying on the grate 'lit' the next load heaped on top.

Regarding Andrew's explanation that the technique was used because of
poor CO performance as the char burned out, I point out that makes it
sound like it wasn't successful, whereas actaully it was successful!
Correctly timing the addition of fresh fuel eliminated the CO
emissions and kept good combustion going throughout.

Yours, Dave.
PS Where was your initials conversion table?

TBR
> AJH and Ron:
>
> I don't understand residual char "kick starting" the next load. In my
> experience, any fire at the bottom of the unit gobble up all the oxygen, so
> none can arrive at the top and you then have an updraft gasifier.
>
> TOM REED
>**********************************************
** **
** Note temporary home telephone number !! **
** **
**********************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From BeedieD at Cardiff.ac.uk Wed Jul 16 12:51:46 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:29 2004
Subject: Top-lit charcoal kiln (Heggie)
Message-ID: <423D64A0854@nrd1s.cf.ac.uk>

Ron,

<snip>
> >With this in mind I have
> >privately e-mailed David Beedie and hope for some collaboritive effort! I
> >feel even if a high tech system is developed the spin of for domestic
> >woodburning stoves may well be worthwhile.
>
> (RWL): I hope that David and you will also keep us informed of anything
> not too proprietary.

Certainly. Nothing proprietary to inform you about either at the
moment!

Dave B.
**********************************************
** **
** Note temporary home telephone number !! **
** **
**********************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From BeedieD at Cardiff.ac.uk Wed Jul 16 13:10:40 1997
From: BeedieD at Cardiff.ac.uk (David Beedie)
Date: Tue Aug 31 21:35:29 2004
Subject: correlation of CO with other pollutants
Message-ID: <42440903A87@nrd1s.cf.ac.uk>

Alex,

I replied with the Hubbard references earlier today to Steven Gust and
'stoves' so if you're interested you can see that email. Haven't had
a chance to read the Tiegs article yet ...

Dave.

> From: "*.English" <english@adan.kingston.net>
> To: stoves@crest.org
> Date sent: Mon, 14 Jul 1997 21:50:38 -0500
> Subject: Re: correlation of CO with other pollutants
> Send reply to: stoves@crest.org

> Dear David
>
> > Alex,
> > A relevant name comes to mind - papers have appeared by Hubbard in
> > 1990s conferences - I don't have the references handy. If you can't
> > easily do an abstract search I'll hunt them out...
>
> AE: I can't easily do an abstract search, but I am willing to drive
> into Queens U. and try. I was just rereading the Paul Tiegs article,
> referred to in an earlier email today. I think it speaks to this issue
> of linking CO emissions to the other nasties. I would be interested
> in your thoughts and others too.
>
> Alex
>
> > I believe many correlations were fairly equipment-specific but some
> > general ones held.
>
> > **********************************************
> > ** **
> > ** Note temporary home telephone number !! **
> > ** **
> > **********************************************
> > (Dr) David Beedie
> > School of Engineering, University of Wales, Cardiff, UK
> >
> > email: BeedieD@cardiff
> >
> > Office Tel. 01222 874683; 874000 ext.5927(lab.)
> > Office FAX: 01222 874420 - mark for my attention !
> > Home tel: 481424 (temporary number ...)
> > *******************************************************
> >
> >
> Alex English
> RR 2 Odessa Ontario
> Canada K0H 2H0
> 613-386-1927
> Stoves Web Site http://www1.kingston.net/~english/Stoves.html
>**********************************************
** **
** Note temporary home telephone number !! **
** **
**********************************************
(Dr) David Beedie
School of Engineering, University of Wales, Cardiff, UK

email: BeedieD@cardiff

Office Tel. 01222 874683; 874000 ext.5927(lab.)
Office FAX: 01222 874420 - mark for my attention !
Home tel: 481424 (temporary number ...)
*******************************************************

From verhaarp at janus.cqu.edu.au Wed Jul 16 18:01:41 1997
From: verhaarp at janus.cqu.edu.au (Peter Verhaart)
Date: Tue Aug 31 21:35:29 2004
Subject: CO production and quenching (English)
Message-ID: <1.5.4.32.19970716213127.006b1f74@janus.cqu.edu.au>

>From Piet Verhaart
Add to the glossary (PV)

To Alex

At 22:17 15/07/97 -0500, you wrote:
>
>Dear Tom +
>
>
>> Hi:
>> As I remember, the pots on my mother's (blue flame) stove sat about 2 cm
>> above the VISIBLE flame.
>AE: The flame on the stove at my folks cottage touches the pan when
>it is turned up.
>> I have always assumed that the VISIBLE edge of
>> the flame was where combustion reactions were completed. Does anyone have
>> information to the contrary?
>
>AE: What is complete, zero CO ?
>
> Help me design an experiment. I am thinking of using a small propane
>torch with an insulated chimney, 5cm in diameter and 50cm tall. If
>there is a declining CO reading at increasing distances above the
>flame would this indicate that combustion is continuing past the
>visible edge of the flame ?
>
>Alex
>
>
>>
>> TOM REED
>>
>>
>Alex English
>RR 2 Odessa Ontario
>Canada K0H 2H0
>613-386-1927
>Stoves Web Site http://www1.kingston.net/~english/Stoves.html
>
>What you have to watch out for is chimney draft upsetting the combustion
process in the propane flame. Have a damper at either end of the chimney.
Apart from that, yes, I think you could find out if there is combustion
after the flame.
Best of luck.
Piet
Peter Verhaart 6 McDonald St Gracemere Q 4702 Australia
Phone: +61 79 331761 Fax: +61 79 331761 or 332112
E-mail:p.verhaart@cqu.edu.au

From owner-stoves at crest.org Wed Jul 16 22:31:31 1997
From: owner-stoves at crest.org (by way of larcon@sni.net Ronal W. Larson)
Date: Tue Aug 31 21:35:30 2004
Subject: Prasad on "correlation of CO with other pollutants"
Message-ID: <v01540b00aff30792f631@[204.133.251.3]>

Stovers - again - for some reason, this message from Prasad "bounced" - Ron

To:David Beedie, Alex English, Grant Ballard-Tremeer and othe stovers

From:K.Krishna Prasad

Date:16 July, 1997

Sub:Correlation between CO and particulates

Paul Bussmann in his thesis has a graph showing the correlation between CO
and unburnt hydrocarbons. That such a correlation exists can also be inferred
from the data presented by Kirk Smith (See pages 279-281 of his book
Biofuels, Air Pollution and Health, Plenum Press, 1987).

The problem here is that the measurements were all carried out in the
chimney of a stove.

Whether the situation is valid for an open fire, or for measurements in a
ventilated room, is anybody's guess. And out in the open the correlation, I
believe, is extremely difficult to establish. Willy-nilly we will get into
discussions of the sort we have heard in one of the sister groups here on
global warming.

This I doubt will answer any questions on the problem. But I thought I'd
throw my hat in the ring.

Prasad

From E.Moerman at stud.tue.nl Thu Jul 17 07:01:22 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:30 2004
Subject: Top-lit moisture research
Message-ID: <3709.s335192@popserver.tue.nl>

Thomas Reed:

> The question of moisture in the top down charcoal experiment is all
> important. As the top layer is ignited, it must dry and ignite the next
> lower layer for the reaction to proceed. It that lower layer is 50%
> moisture there is no way it can continue. 20% maybe. 10% certainly. I
> reported on the dynamics of propogation in 1984 for forced convection
> gasifiers, but would love to study it for natural convection. =

Etienne:
We did some experiments in the downdraft stove. White Fir with a moisture
content over 50% still burnt, only just below 70% problems occurred.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Thu Jul 17 07:01:22 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:30 2004
Subject: Emission measurements
Message-ID: <3714.s335192@popserver.tue.nl>

Grant Ballard-Tremeer:

> I'm concerned about how and where CO measurements are being made. Perhaps
> these points are obvious:
> 1) is there adequate mixing of the combustion gases before they reach the
> gas probe?
> 2) if there is any dilution of the gases from outside air, is it either
> measured or known to be constant?
> 3) are measurements always being made the same distance from the fire?
> 4) since emissions frequently vary rapidly, are there enough readings to be
> able to average them and make a little more sense of comparisons? I prefer
> quoting emissions in grammes per task since this correlates well with
> exposure (but one needs some fairly complex calibrated equipment for
> this).
> 5) there are three (fairly simple) ways of measuring particulates for these
> types of stove: my way: (using a light obscuration meter) gives 'real-time'
> output, good for comparisons, but must be calibrated if more detail is
> needed; Kirk Smith's way (using personnel monitors with filters) averages
> over the burn cycle but requires a sensititive mass balance; and Jurgen
> Usinger's way (of HEAT International, using a hand pump and filter spot)
> gives a good visual indication of indoor pollution levels in the field.

Etienne:
At least for CO not the CO concentration should be given, but the CO/CO2
ratio. Since CO and CO2 from the fire both dilute at the same rate points
(2), (3) and (4) are no problem any more. Using the mass loss of the fire
and the composition of the fuel it is easy to convert the CO/CO2 ratio into
a source term in mass terms.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From E.Moerman at stud.tue.nl Thu Jul 17 07:01:22 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:30 2004
Subject: correlation of CO with other pollutants
Message-ID: <3705.s335192@popserver.tue.nl>

For a correlation of CO and CxHy (unburnt hydrocarbons) see page 28 of Paul
Bussmann's thesis.

Woodstoves-theory and applications in developing countries. P.J.T Bussmann.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From Akuo710 at aol.com Thu Jul 17 16:08:25 1997
From: Akuo710 at aol.com (Akuo710@aol.com)
Date: Tue Aug 31 21:35:30 2004
Subject: RootFuels
Message-ID: <970717160832_-23086079@emout16.mail.aol.com>

Hello, I'm a debater reseraching the efficacy of root/gourd based fuels...if
you have any information, websites, articles, etc. I would much appreciate
it.

Thank you!

Sincerely,
Alex Kuo

From ahe1 at cableol.co.uk Fri Jul 18 06:27:13 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:30 2004
Subject: Top-lit moisture research
Message-ID: <9707181027.AA04989@mars.cableol.net>

Andrew Heggie in reply to Tom Reed who, at 18:48 14/07/97 -0400, wrote:

>I have long planned a study on the effect of moisture in the small stoves.
>A simple experiment:
>
>1) Take a standard fuel - ie 1" square wood blocks
>
>2) Oven dry them to 0% moisture (4 hr at 220F)
>
>3) Place them in plastic bags with the necessary amount of moisture to
>give 10%, 15%, 20%, 30% and wait a week or two for equilibrium to be
>established (no visible water in bags)
>
>4) Fill the stove with wet wood and one layer of dry wood on top for
>starting
>
>5) Start the stove and observe time of propogation and yield of charcoal.
>I am sure that at a sufficiently high moisture content the fire will
>extinguish.
(Andrew): I take your point, however I have extremely limited ability to
experiment and so wish to understand the principles that my test might have
a decent chance, on your and Ronal's advice we shall delay top lighting
until we are able to use drier wood. In the meanwhile we attempt to flare.

Returning to your experiment and your previous post regarding autopyrolysis,
would a suitable apparatus be made from an old metal vacuum flask. I am
thinking of loading the flask with bone dry wood and top lighting, once
burning to place a long tube over the flask with a sand seal to prevent air.
I need a suggestion for the length of tube and a diameter such that a flare
at the top is unlikely to burn back down the tube and allow air to reach the
reaction.
AJH

From skip.hayden at cc2smtp.NRCan.gc.ca Fri Jul 18 16:03:07 1997
From: skip.hayden at cc2smtp.NRCan.gc.ca (Skip Hayden)
Date: Tue Aug 31 21:35:30 2004
Subject: CO production (Larson)
Message-ID: <9706188692.AA869266977@cc2smtp.nrcan.gc.ca>

For your info:

Just received my June/97 issue of Environmental Science and
Technology. There is a good article by H.Keith Florig
(Carnegie-Mellon), entitled "China's Air Pollution Risk", which
illustrates that CHina's most serious health problem is indoors, due
to stoves. ref: pp 274A-279A, Vo.31, no.6, 1997, ENVIRONMENTAL
SCIENCE AND TECHNOLOGY.

Skip Hayden
Advanced Combustion Technologies
Ottawa, Canada K1A 1M1
TEL: (613) 996-3186
FAX: (613) 992-9335
e-mail: skip.hayden@nrcan.gc.ca-

______________________________ Reply Separator _________________________________
Subject: Re: CO production (Larson)
Author: stoves@crest.org at internet
Date: 7/8/97 10:55 AM

Ronal W. Larson writes:
> (RWL): 1. Skip - Do some or most of these tragedies occur as the oxygen in
> the room is depleted?
> 2. Since most third world stove rooms are much less tight, should
> this be a smaller problem overseas?

Etienne:
The most important cause here seems to be no or bad maintenance of the
burners. Of cause this is made more severe in well insulated spaces.

------

Ronal W. Larson writes:
> 4. Have you ever measured the CO emissions from charcoal-burning
> stoves - and can you guess as to why CO emissions are or could be higher
> from such stoves? (and how to minimize the emissions?)
>

Etienne:
I did do these measurements. My guess as to why emissions are high(er) is
that the charcoal combustion occurs at the surface of the charcoal to CO.
For this the diffusion process is very important. If diffusion is sufficient
some surface combustion can occur to CO2. A secondary reaction CO->CO2 in
the gas phase occurs in a small flame enveloping the piece of char. Again
diffusion is very important, insufficient diffusion means high CO levels.
The small flame is usually only a little larger than the piece of char on
which it 'feeds', this means a very little mixing length. Also I suspect
that the reaction temperature at the charcoal surface is substantially lower
than the reaction (adiabetic) flame temperature of the volatiles. Our
thermocouple measurements seem to indicate this. However I don't think
thermocouples are appropriate for the measurement of these reaction
temperatures.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From english at adan.kingston.net Fri Jul 18 20:25:44 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:30 2004
Subject: CO production and quenching (English)
In-Reply-To: <199707151257_MC2-1AEA-33A@compuserve.com>
Message-ID: <199707190026.UAA31660@adan.kingston.net>

Summary: " Time and temperature" reduce CO emissions from a propane
torch.

> Hi:
>
> As I remember, the pots on my mother's (blue flame) stove sat about 2 cm
> above the VISIBLE flame. I have always assumed that the VISIBLE edge of
> the flame was where combustion reactions were completed. Does anyone have
> information to the contrary?
>
> TOM REED

Dear Tom, Peter, +

An afternoon thunderstorm forced me away from my ' hay-cation' and
back to more important work.

I made a chimney for a small propane torch with a 46cm piece of
schedule 40 pipe (about 5mm wall thickness), 5cm inside dia., wrapped
in insulation. The torch pointed vertically up through some
insulation (a damper) into the bottom of the chimney about 5cm. The
visible flame extended about 10cm. There were to sample points, the
lower one about 3cm above the tip of the visible flame and a higher
point about 18cm above that. The chimney extended, damperless, about
12cm above the higher point.

After lighting the torch, readings dropped constantly for at
least the first ten minutes, presumably due to the heating up of the
chimney. With CO2 around 6%, CO started out over the instrument limit
of 2000ppm but dropped steadily to a stable 17ppm at the high sample
point(HSP) and 35ppm at the low sample point (LSP). Then, adjusting
the chimney air supply to a CO2 of 9% resulted in CO levels of 7 ppm
at HSP and 90ppm at LSP.

A second test, starting from cold, and at a higher burn rate, with
CO2 at 8%, had levels dropping from around 60ppm CO at HSP,at the one
minute mark, down after 5 minutes to a stable 0 ppm CO at HSP
while 12ppm at LSP. I think this points to the early
high readings on the first test being due to the burn off of dust and
the like. At the end of the second burn the chimney was removed and
levels of 200 to 600ppm CO were recorded from about 10cm above the
flame down to the flame tip, respectively. No CO2 levels were
attempted for this circumstance. I assumed, and perhaps I shouldn't
that there must have been a greater excess air factor, further
highlighting the contrast.

Conclusive Speculation:
I can see many ways in which these test conditions are different from
a stove top but there appears to be a strong correlation between CO
and temperature, and some evidence of continued combustion beyond
the visible flame. I would think that stove top CO emissions would
suffer from poor temperatures, and that higher excess air levels
may only add to the quenching.
Comments anyone ?

Alex
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From Tjreardon at btinternet.com Sat Jul 19 11:15:22 1997
From: Tjreardon at btinternet.com (Terence Reardon)
Date: Tue Aug 31 21:35:30 2004
Subject: No Subject
Message-ID: <MAPI.Id.0016.006a72656172646f4241413330303030@MAPI.to.RFC822>

hi ,I,m not sure if your the right place to call.
I,m interested in charcoal making

From ofb-inc. at ix.netcom.com Wed Jul 23 04:54:50 1997
From: ofb-inc. at ix.netcom.com (Gregory C. Brown)
Date: Tue Aug 31 21:35:30 2004
Subject: Top-lit moisture research
Message-ID: <199707230855.DAA08594@dfw-ix11.ix.netcom.com>

Dear Andrew,
Have you had time to try out the starter? Am interested in hearing
any ideas that you have concerning same.
Are you familiar with Pang Valley Charcoal? Teale, Berkshire, UK

Their web page is at http://www.netscope.co.uk/pangvall/index.html

more later...Greg

From REEDTB at compuserve.com Wed Jul 23 10:39:11 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:30 2004
Subject: CO production and quenching (English)
Message-ID: <199707231038_MC2-1B72-969E@compuserve.com>

I am jealous of your CO/CO2 meter and might even buy one. Meanwhile, I am
so glad you are running these real tests on real fires to keep all of us
aware of our realities in the stove business.

Cooks don't usually place their samplers (noses) directly over the flame.
How are the CO levels in the room during these tests?

TOM REED

From jflores at prolena.sdnhon.org.hn Wed Jul 23 15:55:04 1997
From: jflores at prolena.sdnhon.org.hn (jflores@prolena.sdnhon.org.hn)
Date: Tue Aug 31 21:35:30 2004
Subject: Woodstove training
Message-ID: <199707231744.NAA00698@sdnhon.org.hn>

Hi stover.

How you know, PROLENA is working in a woodstove project. Now, we are
working in development some training courses for the people, so, we
have to prepare material, brochure, and another kind of material. We
aren't sure about the methodology that we can use for doing that. I
want your help on it.

Saludos

Juan Carlos

From ahe1 at cableol.co.uk Wed Jul 23 17:37:36 1997
From: ahe1 at cableol.co.uk (Andrew Heggie)
Date: Tue Aug 31 21:35:30 2004
Subject: Top-lit moisture research
Message-ID: <9707232138.AA07692@mars.cableol.net>

At 03:55 23/07/97 -0500, you wrote:
>Dear Andrew,
> Have you had time to try out the starter? Am interested in hearing
>any ideas that you have concerning same.
Yes, I have used it for lighting and attached it to a chimney for flaring,
it lights well as you say, I was unable to flare with it. I am going to boil
a pot on it and it is laded ready to go, I keep forgetting when I come home.
I think it is very similar to the ordinary Jiko as I mentioned, I know
little about these but from the lighting experiments I think it is too
powerfull for most cooking, as you also thought, and I will try to alter the
primary air. Strangely enough my wife has now seen them advertised in
magazines here, albeit at 18gbp
> Are you familiar with Pang Valley Charcoal? Teale, Berkshire, UK
Yes I have spoken with them and have attended coppice mamagement discussions
with them.
>
> Their web page is at http://www.netscope.co.uk/pangvall/index.html
>
> more later...Greg

I am struggling to make good my losses at the moment, Tom Reed seems to be
sniping that I have not managed to do any experiments, yet he will not
answer questions about his posts!.

Thganks for pointing me to the REUR booklet, very interesting, it looks to
me we should be aiming mid way between "full" charcoal and torrefied wood
with regards to yiels, hygroscopy and machanical strength. Very interesting
the section on rate of loss of waste gases being constant over time,
explains why wet wood simply takes longer, also surprising how minor the
losses from the kiln walls were.

AJH

From ROCKYROADRANCH at libby.org Wed Jul 23 23:32:55 1997
From: ROCKYROADRANCH at libby.org (Miller)
Date: Tue Aug 31 21:35:30 2004
Subject: Monarch refurbishment
Message-ID: <199707240333.VAA09863@homer.libby.org>

A non-text attachment was scrubbed...
Name: not available
Type: text/plain
i recently obtained an antique monarch cookstove in reasonable condition. grates and all casting seems to be quite sound. extensive nickel plating in excellent shape. surface rust and general enamel restorable. i am however in need of a door thermometer and other asundry parts. do you or any of your web followers know of a source for parts ? other stoves in my collection (also monarchs) include a large white enamel unit in need of fire box cover and plates, as well as water heater insert. any help would be gladly accepted. respond to miles : rrranch@libby.org thanx
Size: 1 bytes
Desc: not available
Url : http://listserv.repp.org/pipermail/stoves/attachments/19970723/a64405bd/attachment.bin
From rmiranda at sdnnic.org.ni Thu Jul 24 11:17:34 1997
From: rmiranda at sdnnic.org.ni (Rogerio Carneiro de Miranda)
Date: Tue Aug 31 21:35:30 2004
Subject: Woodstove training
Message-ID: <199707240920.JAA02571@ns.sdnnic.org.ni>

Dear Juan carlos: can you be more specific about the methodology that you
are searching for ? I believe you must be talking about what kind of
trainiing, improved woodstove cookers around developing world must have in
order to make a better use from their cookstove.

We face the same problem here in Nicaragua, e.g., what are the tips for
cookers in how to get the best efficiency from its Plancha stove, as well as
how to keep indoor air pollution at the minimun level?

Who has done similar traiining before ?

Rogerio

At 01:43 PM 7/23/97, you wrote:
>Hi stover.
>
>How you know, PROLENA is working in a woodstove project. Now, we are
>working in development some training courses for the people, so, we
>have to prepare material, brochure, and another kind of material. We
>aren't sure about the methodology that we can use for doing that. I
>want your help on it.
>
>
>Saludos
>
>
>Juan Carlos
>
>
>----------------------------------------------------------------------
>Juan Carlos Flores Lopez
>Director Ejecutivo PROLENA/Honduras
>Tel/Fax: (504) 32-0639
>P.O.Box 3870 Tegucigalpa, Honduras.
>E-Mail: jflores@prolena.sdnhon.org.hn
>----------------------------------------------------------------------
>
>
----------------------------------------------------------------------------
------------------------------------------------------------------------------
Rogerio Carneiro de Miranda Telefax: (505) 276 2015
PROLENA(Nicaragua)
Apartado Postal C-321 Managua Nicaragua
E-mail: rmiranda@sdnnic.org.ni
----------------------------------------------------------------------------
------------------------------------------------------------------------------

From english at adan.kingston.net Thu Jul 24 22:24:41 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:30 2004
Subject: Wood Gas Stove Pictures
Message-ID: <199707250225.WAA05907@adan.kingston.net>

Dear Stovers
Tom Reed has sent me some information that I hope will soon find its
way onto the webpage. I have started by putting one picture and on
drawing of the stove that he and Ron Larson have been working on.

Question for Tom or Ron: Is the coffee can model in the picture
insulated as shown in the drawing ?

Alex
Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From mike at esd.co.uk Fri Jul 25 03:55:32 1997
From: mike at esd.co.uk (Mike Bess)
Date: Tue Aug 31 21:35:30 2004
Subject: Woodstove training
In-Reply-To: <199707231744.NAA00698@sdnhon.org.hn>
Message-ID: <r18LPAA1i51zUAbn@esd.co.uk>

Dear Juan Carlos,

Your wrote
>How you know, PROLENA is working in a woodstove project. Now, we are
>working in development some training courses for the people, so, we
>have to prepare material, brochure, and another kind of material. We
>aren't sure about the methodology that we can use for doing that. I
>want your help on it.
>
We have developed training modules for stove producers for the
production and efficiency aspects, and more importantly, for the
business practices and management aspects. We have notes and
presentations for our Ethiopian work on small business practices, on
bookkeeping, promotion, customer relations, quality control, marketing,
stocks, etc. We would be happy to send you those (they are in both
English and Amharic), if you would like. All the best, Mike Bess
--
Mike Bess

From REEDTB at compuserve.com Fri Jul 25 07:45:43 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:30 2004
Subject: Chinese Fuel Saving Stoves
Message-ID: <199707250740_MC2-1B92-6211@compuserve.com>

I just received (free) in the mail the publication: Chinese Fuel Saving
Stoves - RAPA publication 1986/25, from the regional office for Asia and
the Pacifica (RAPA), Food and Agriculture Organization (FAO) of the UN .

It has 30 pages of the most beautiful color pictures I have ever seen of
about 8 stove designs, along with excellent drawings. It also has an
Appendix (Annexure!) Testing Method for the Heat Properties of Civil Fuel
Stoves (as ratified by the Bureau of State Standards of China). The stoves
range from simple to complex, are generally laid up with common brick, but
have a few cast iron parts where needed. These stoves have reached 40
million households.

This book should be on all our shelves. It also says, "For Copies, write
to "Regional Forestry Officer, FAO Regional Office for Asia and the
Pacific; Maliwan Mansion, Phra Atit Road, Bangkok, Thailand.

Sorry to say, no mention of gas cook stoves, but this may represent a high
water mark for non-gasifier cook stoves. They claim the stoves have an
efficiency >40% and heat wter at 4 C/min. Uses half as much energy as
previous stoves.

When I visited China in 1992 they had developed a wood-gas stove, more
elegant than anything we have discussed, less elegant than my grandmothers
washday gas stove. Unfortunately it was a conventional downdraft gasifier
stove, so required about 50 W of power from the (ha ha) grid. So when
everyone wanted to cook, the grid was "cooked".
Regards, TOM

From jflores at prolena.sdnhon.org.hn Fri Jul 25 10:30:57 1997
From: jflores at prolena.sdnhon.org.hn (jflores@prolena.sdnhon.org.hn)
Date: Tue Aug 31 21:35:30 2004
Subject: Woodstove training
Message-ID: <199707251234.IAA07385@sdnhon.org.hn>

!!Fecha envio: Thu, 24 Jul 1997 19:02:29 +0100
!!A: stoves@crest.org
!!De: Mike Bess <mike@esd.co.uk>
!!Asunto: Re: Woodstove training
!!Enviar resp a: stoves@crest.org

!!Dear Juan Carlos,
!!
!!Your wrote
!!>How you know, PROLENA is working in a woodstove project. Now, we are
!!>working in development some training courses for the people, so, we
!!>have to prepare material, brochure, and another kind of material. We
!!>aren't sure about the methodology that we can use for doing that. I
!!>want your help on it.
!!>
!!We have developed training modules for stove producers for the
!!production and efficiency aspects, and more importantly, for the
!!business practices and management aspects. We have notes and
!!presentations for our Ethiopian work on small business practices, on
!!bookkeeping, promotion, customer relations, quality control, marketing,
!!stocks, etc. We would be happy to send you those (they are in both
!!English and Amharic), if you would like. All the best, Mike Bess
!!--
!!Mike Bess

JCF> Dear Mikes. Thank you very much, I'ld like you to send
me those book. My address is at the end of the massages. Thank you.

Saludos

From jflores at prolena.sdnhon.org.hn Fri Jul 25 10:31:04 1997
From: jflores at prolena.sdnhon.org.hn (jflores@prolena.sdnhon.org.hn)
Date: Tue Aug 31 21:35:30 2004
Subject: Woodstove training
Message-ID: <199707251234.IAA07384@sdnhon.org.hn>

!!Fecha envio: Thu, 24 Jul 1997 09:20:45 GMT
!!A: stoves@crest.org
!!De: Rogerio Carneiro de Miranda <rmiranda@sdnnic.org.ni>
!!Asunto: Re: Woodstove training
!!Enviar resp a: stoves@crest.org

!!Dear Juan carlos: can you be more specific about the methodology that you
!!are searching for ? I believe you must be talking about what kind of
!!trainiing, improved woodstove cookers around developing world must have in
!!order to make a better use from their cookstove.

JCF> Yes, you are right. I'm looking for some experiences in
training and how we can use this to improved the social condition
of the poor people.

!!We face the same problem here in Nicaragua, e.g., what are the tips
for
!!cookers in how to get the best efficiency from its Plancha stove, as well as
!!how to keep indoor air pollution at the minimun level?
!!
!!Who has done similar traiining before ?
!!
!!Rogerio
!!
!!At 01:43 PM 7/23/97, you wrote:
!!>Hi stover.
!!>
!!>How you know, PROLENA is working in a woodstove project. Now, we are
!!>working in development some training courses for the people, so, we
!!>have to prepare material, brochure, and another kind of material. We
!!>aren't sure about the methodology that we can use for doing that. I
!!>want your help on it.
!!>
!!>
!!>Saludos
!!>
!!>
!!>Juan Carlos
!!>
!!>
!!>----------------------------------------------------------------------
!!>Juan Carlos Flores Lopez
!!>Director Ejecutivo PROLENA/Honduras
!!>Tel/Fax: (504) 32-0639
!!>P.O.Box 3870 Tegucigalpa, Honduras.
!!>E-Mail: jflores@prolena.sdnhon.org.hn
!!>----------------------------------------------------------------------
!!>
!!>
!!----------------------------------------------------------------------------
!!------------------------------------------------------------------------------
!!Rogerio Carneiro de Miranda Telefax: (505) 276 2015
!!PROLENA(Nicaragua)
!!Apartado Postal C-321 Managua Nicaragua
!!E-mail: rmiranda@sdnnic.org.ni
!!----------------------------------------------------------------------------
!!------------------------------------------------------------------------------
!!

From budman at acc-net.com Fri Jul 25 23:32:33 1997
From: budman at acc-net.com (Johnson, Joe & Jackie)
Date: Tue Aug 31 21:35:30 2004
Subject: No Subject
Message-ID: <19970726004813957.AAA313@default>

I have recently acquired an old gas stove that needs to be put back
together. The pieces are all with it but it's in parts. The exterior is
in very good condition. Could you please refer me to someone in Ohio or
near Ohio that would be able to fix it. It has a sign on it saying
"American Stove Co. " St. Louis MO.
I do not care if it's original or if new parts need to be added. I am at
my wits end trying to find someone to touch it!!!!!!!
THank you for your time. .
Jackie Johnson
614.387.3882
budman@acc-net.com

From dfox at blarg.net Sat Jul 26 23:06:07 1997
From: dfox at blarg.net (David G. Fox)
Date: Tue Aug 31 21:35:30 2004
Subject: electric/wood stove
Message-ID: <33DABBE1.15C312AB@blarg.net>

Hi,
I saw your letter while trying to find out how to get rid of the old
stove in my basement. It's from the late forty's and as far as I can
tell
it is called a "Prosperity" though I don't know weather that's the brand
or model
name. It's got four burners and an oven as well as some sort of double
boiler device.
It's still plugged in and works fine ... though I've never tried the
wood burner.
It could use a little restoration but is in good shape.
Does this help ?

dfox

From english at adan.kingston.net Sun Jul 27 14:25:28 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:30 2004
Subject: Top-lit moisture research
In-Reply-To: <3709.s335192@popserver.tue.nl>
Message-ID: <199707271826.OAA03697@adan.kingston.net>

Dear Ettiene
Summary:Fuel moisture effects on Emissions

> Thomas Reed:
>
> > The question of moisture in the top down charcoal experiment is all
> > important. As the top layer is ignited, it must dry and ignite the next
> > lower layer for the reaction to proceed. It that lower layer is 50%
> > moisture there is no way it can continue. 20% maybe. 10% certainly. I
> > reported on the dynamics of propogation in 1984 for forced convection
> > gasifiers, but would love to study it for natural convection. =
>
>
> Etienne:
> We did some experiments in the downdraft stove. White Fir with a moisture
> content over 50% still burnt, only just below 70% problems occurred.

What happened to the CO/CO2 ratio when you used fuel with a higher
moisture content? Was there any indication that temperatures were
reduced enough to inhibit CO conversion ?

From unique at form-net.com Mon Jul 28 08:02:01 1997
From: unique at form-net.com (Mr. Vincent Mwenyinyo Malingu)
Date: Tue Aug 31 21:35:30 2004
Subject: SAWDUST GASIFICATION PLANT
Message-ID: <33DC6A4B.4DF6@form-net.com>

TOM REED

JUST INSTALLED AT HUGE COST A GASIFIER. WE HAVE A DEFORESTATION PROBLEM
IN KENYA AND THIS IS OUR CONTRIBUTION. WE PRODUCE 10000000 TONS OF
AGRO-WASTE EVERY YEAR.
WHICH INDUSTRIES ARE OUR POTENTIAL CUSTOMERS?
WHICH EXPERTS ARE CLOSE AT HAND?
WHERE ARE THERE SUCCESFUL SIMILAR PROJECTS?

REGARDS
JIM SHAMOON

From english at adan.kingston.net Tue Jul 29 00:07:11 1997
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:35:30 2004
Subject: Bluff Body Babble
Message-ID: <199707290301.XAA30668@adan.kingston.net>

Dear Stovers
Summary; Conical Bluff Body Improves Venturi Burner

I took some time today to rework the venturi burner. I took an old
milking machine pail, 30cm in dia. and 30cm tall, that had
a tapered top that would match the bottom cone of my burner. I
drilled primary air holes in the raised bottom and shimmed it up
1cm with sand spread around the bottom rim as the primary air damper.
This allows for under fuel air as Ron and Elsen have been
using. Taking the falling cone/venturi arrangement, I installed a
solid cone buff body, 10cm long by 6cm at the wide end , point down
on a sliding shaft that allows it to be raised and lowered in the
top half of the venturi, with a control mechanism in the lower half.
Remember folks , this is research.

This assembly then sits stationary on top of the milk can with a
donut shaped piece of insulation inbetween to seal the joint. I have
cut down the insulated combustion chamber/chimney to 23cm with the
option to place an additional piece of 15cm dia.stove pipe on top.

On startup, with the additional 60cm long stove pipe chimney, the
stove billowed smoke until I placed a match by the secondary venturi
intake air holes. It then burned with a vigorous turbulent flame.
The bluff body cone forced the flame into an even circular
distribution in full contact with the swirling secondary air. The
entire insulated portion of the chimney glowed red. CO was over
2000ppm which confused me until I checked CO2, at 20%. Shutting of
some of the primary air shortened the flame and brought CO down to
17ppm with CO2 at 13%. (CO/CO2=.00013) The top of the bluff body was
also red and I was speculating that it may be wicking heat down into
the centre of the venturi. I could not tell where the secondary flame
started. There were a few small pilots extending up from some leaks
in the lower cone, but nothing like the strong flame that the falling
cone produced. It may be that the lower point of the glowing bluff
body acts as an ignition point. The only thing that threatened the
flame was completely cutting off the primary air. The wind only
added draft and vigour.

Removing the 60cm chimney extension dampened the fire considerably.
With the turbulence gone the flame maintained a gentle " gas stove "
appearance, only taller and with six distinctive attachment points to
match the venturi intake pattern. The CO2 readings, keeping in mind
these are 40second averages, remained at 13%. CO, which is monitored
continuously , jumped around between 200-700ppm.

The movement, up and down 8cm, of the bluff body had only marginal
effect on the flame. It needs to have its range of movement extended
down further.

All in all, this has moved my experiment much closer to being
something which could be cooked upon.

Yahoo, Alex

Alex English
RR 2 Odessa Ontario
Canada K0H 2H0
613-386-1927
Stoves Web Site http://www1.kingston.net/~english/Stoves.html

From E.Moerman at stud.tue.nl Tue Jul 29 11:25:30 1997
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:35:30 2004
Subject: Top-lit moisture research
Message-ID: <19571.s335192@popserver.tue.nl>

Summary:Fuel moisture effects on Emissions
>
>> Etienne:
>> We did some experiments in the downdraft stove. White Fir with a
>> moisture content over 50% still burnt, only just below 70% problems
>> occurred.
>
Alex:
> What happened to the CO/CO2 ratio when you used fuel with a higher
> moisture content? Was there any indication that temperatures were
> reduced enough to inhibit CO conversion ?
>

Etienne:
I don't remember the effect on CO/CO2. These measurements were published in
a student report and I was only interested in the mass loss rate. I will see
if I can find the report agian.

Etienne
---------------------------------------------
Mr. Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From REEDTB at compuserve.com Tue Jul 29 16:16:56 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:30 2004
Subject: SAWDUST GASIFICATION PLANT
Message-ID: <199707291617_MC2-1BD4-BFE9@compuserve.com>

>JUST INSTALLED AT HUGE COST A GASIFIER. WE HAVE A DEFORESTATION PROBLEM IN
KENYA AND THIS IS OUR CONTRIBUTION. WE PRODUCE 10000000 TONS Of AGRO-WASTE
EVERY YEAR.

WHICH INDUSTRIES ARE OUR POTENTIAL CUSTOMERS?

What kind of gasifier, and what use? How much? What make? Best use is
to produce power, but you need distribution system.

WHICH EXPERTS ARE CLOSE AT HAND?

WHERE ARE THERE SUCCESFUL SIMILAR PROJECTS?

REGARDS

JIM SHAMOON

Jim, you should join the GASIFICATION network and I'll put your questions
there. Join by sending the message "subscribe gasification" to
majordomo@crest.Org.
Since I don't know Kenya, I don't know what experts may be close and what
successful projects are nearby. There is a rice hull gasifier that has
been operating for 20 years in Mali. I hope others can answer your
questions.

Good luck, TOM REED Gasification webmaster

From REEDTB at compuserve.com Tue Jul 29 16:19:37 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:30 2004
Subject: Top-lit moisture research
Message-ID: <199707291617_MC2-1BD4-BFE6@compuserve.com>

Ettienne says that they burned pine with 50% moisture, but had trouble at
70%. This indicates to me that he is talking about the moisture content
measured on a dry basis, ie
MC (dry basis) = Weight of water/weight of dry wood

MC (wet basis) = weight water/weight of water plus wood
And
WB = DB/(DB + 1)
So Etienne's 50% (0.5) on a dry basis was 33% WB .

We need to run tests.

In particular we don't know what the superficial velocity (SV) of the
Eindhoven downdraft stove was, so we're comparing maybe apples and oranges.
Can you take a guess Ettienne?

TOM

From verhaarp at janus.cqu.edu.au Wed Jul 30 01:42:42 1997
From: verhaarp at janus.cqu.edu.au (Peter Verhaart)
Date: Tue Aug 31 21:35:30 2004
Subject: Mugshots
Message-ID: <1.5.4.32.19970730054231.006bf3f8@janus.cqu.edu.au>

>From Piet Verhaart

The picture of Ronal testing a two-can stove in Tom's kitchen has a
place of honour in my Stoves Archive.
What I sorely miss is a picture of Tom Reed, preferably testing a stove in
Ronal's kitchen.

Bye the way, is there any advantage in having the air conditioner (that is
what I think it was) right above the stove top?
I would expect that to be the place ensuring the maximum amount of fouling
of the evaporator by gooey grease.

Regards to R., T. and all stovers.

Piet
Peter Verhaart 6 McDonald St Gracemere Q 4702 Australia
Phone: +61 79 331761 Fax: +61 79 331761 or 332112
E-mail:p.verhaart@cqu.edu.au

From REEDTB at compuserve.com Wed Jul 30 09:30:41 1997
From: REEDTB at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:35:30 2004
Subject: Bluff Body Babble
Message-ID: <199707300930_MC2-1BEC-3FF1@compuserve.com>

I read your Bluff Body Babble carefully. Don't fully understand, but I'll
print it out and try to make a drawing from it. A drawing on your
wonderful page would help.

My first inverted downdraft (with a forced draft burner) had a ceramic
Venturi and a heavy wire screen at the top to act as flame holder. It
glowed a bright red and made the wood stove look like an electric stove.
The radiation from a six inch diameter black body plate at 800C (1073 K)
would be (5.67*1.07^4*pi/4*15^2) 1.3kW , a respectable output for a stove.
All radiation down went back into the system. Boiled coffee water in a
short time (1985 memory weak).

Paul Hait's Pyromid charcoal stove reinforces our high respect for RADIANT
heating. Sounds like your bluff body could be a good radiator, as well as
good convection heating fromt the flames.

Wish we were in the same room for a day........

Yours truly, TOM REED

From Skarekezi at form-net.com Thu Jul 31 06:35:07 1997
From: Skarekezi at form-net.com (Skarekezi@form-net.com)
Date: Tue Aug 31 21:35:30 2004
Subject: Stoves characteristics (Heggie)
Message-ID: <199707311034.GAA16915@solstice.crest.org>

our ref: rr11797,afr/sec/tech, ro(at,lm)

EMAIL TO: RONAL W. LARSON, 21547 MOUNTSFIELD DR., GOLDEN, CO 8O401,USA.
TEL: 303 526 9629 E-MAIL: IN:stoves@crest.org)

FROM: STEPHEN KAREKEZI, AFREPREN/FWD, ELGEYO MARAKWET CLOSE,KILIMANI,
P.O. BOX30979, NAIROBI, KENYA (TEL: 254 2566032; FAX: 254 2561464/
566231/740524;E-MAIL:Skarekezi@form-net.com or
Stephen_Karekezi@elci.gn.apc.org))

DATE: 30 July, 1997

Dear Ron and stovers,

SUBJECT: STOVES CHARACTERISTICS (HEGGIE)

1. Greetings from AFREPREN/FWD. Please find below the contact address of
Mr.Nilsson who is working in Khartoum together with the Episcopal
Church on woodstoves:

Mr. Arnold Nilsson
P.o. box 1039,
Khartoum,
Sudan.
Fax: 249-11-467213

2. Kindly let us know if you require any additional information or
clarification.

Yours Sincerely,

Stephen Karekezi
AFRPREN/FWD.

BioEnergy Lists: Improved Biomass Cooking Stoves

July 1997 Biomass Cooking Stoves Archive