March 1996 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 E.Moerman at stud.tue.nl Sat Mar 2 06:35:18 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:50 2004
Subject: The need for balance corrections
Message-ID: <45460.s335192@popserver.tue.nl>

To all experimentors-

I noticed that a number of you were gathering equipment to do some
experiments. I would like to point out that if you are doing dynamic weight
measurements with a burning stove you will have to correct for the
temperature-dependant air density. This is especially important for mass
loss rate measurements and measurements that require the absolute weight of
the fuel. I have measured effects of over 12g for a typical 400g fuelweight.
Since this is a point that is easily overlooked I thought I would mention
it.

Good luck everybody with the experiments.

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

From aellegaard at nn.apc.org Mon Mar 11 13:53:25 1996
From: aellegaard at nn.apc.org (aellegaard@nn.apc.org)
Date: Tue Aug 31 21:34:50 2004
Subject: Comments on Tom, Etienne, Ron and msg to all
Message-ID: <199603111957.TAA18035@nn.apc.org>

From aellegaard Mon Mar 11 12:22:18 1996
From: aellegaard (aellegaard)
Date: Tue Aug 31 21:34:50 2004
Subject: Comments to Tom, Etienne, Ron & All
Message-ID: <199603111722.RAA12281@nn.apc.org>

To Tom:
Your little piece on the shoulders of giants: I couldnt make this
quite out. If its ironic, then I want to be the first to
apologize. My intention has never been to be snotty, and I dont
think the tone in the list is at all patronizing from anyone.

To Etienne: re. pollution from charcoal production.
Etienne: Are you sure. Charcoal production is done outside,
while women usually are exposed to it in a closed room.

Anders: Well, Etienne, as far as our monitoring is concerned
there is no question about it. Below some figures. For women,
the figures are during cooking time (avg. 4.5 h fo women in
Lusaka) for charcoal producers (all men) the figure is average
for 2.5 hours working by the kiln. In the open. Concentrations
are averages measured by equipment strapped on to the respondents
(less painful than it seems, they are lightweight).

Particulates, RSP (less 7.2 micrometers), microgrammes/cu.m.
mean s.e. n
Women, Lusaka, charcoal 380 31 95
Women, Lusaka, wood 890 62 89
Women, Lusaka, electricity 240 21 67
Charcoal producers, rural Zambia 1400 190 49

Carbon monoxide. Assessment with Draeger diffusion tubes. Same
procedure as above. (ppm)
mean s.e. n
Women, Lusaka, charcoal 13 7.8 98
Women, Lusaka, wood 8.5 1.1 88
Women, Lusaka, electricity 2.1 0.6 63
Charcoal producers, rural Zambia 13 2.5 44

Carbon monoxide levels are not really disturbing from a health
point of view. The indoor/outdoor distinction is much less rigid
in Lusaka than e.g. in Europe.

To Ron on urban charcoal production:
(Unfortunately my logfile got somewhat garbled, so I missed some
of your comments on pollution from wood vs charcoal)

Charcoal size: Customers prefer large pieces, and then split
them by themselves to fit their stoves. Yes, the pieces are
too big for the stove.

Urban/rural charcoal production: I think it is unrealistic to
make charcoal in the cities. Even if your kiln-stove is very
nice the particulate pollution must be worse, if for no other
reason because there are people in the city who will be
exposed. Also, the transport work of moving all those twigs
would be horrendous. Again, I think it is better to make it in
the rural areas. But admittedly, if it could be made more
efficiently that would be better. And not only from a
thermodynamic perspective, but also from the point of produc-
tivity (tons of charcoal/man hour), and economics (tons of
charcoal / invested Kwacha). Adding the two latter makes the
present system difficult to beat.

Wood is still plenty in Zambia and most of Tanzania. Charcoal
making is legal, provided stumpage and removal fees are paid.
They are (obviously) often evaded, however.

To everybody: I have just been in contact with Stephen Karekezi
(FWD/AFREPREN) on the email. I sent a question asking if he
wanted to join the group. So how do I do to enter him, if he is
interested?

Regards to all
Anders

From asw at crest.org Mon Mar 11 14:03:52 1996
From: asw at crest.org (Andrew S. Waegel)
Date: Tue Aug 31 21:34:50 2004
Subject: Mailing List Services Restored
Message-ID: <v01510102ad69b36420cf@[206.86.125.32]>

Hello-

Following our recent disk failure and subsequent restore, I have
reactivated mailing list services on Solstice. Please contact the list
owner if you have any problems using the list. Thanks, and out apologies
for the interruption.

...Andrew Waegel.asw@crest.org...Internet Services Manager...Center for
...Renewable Energy & Sustainable Technology...http://solstice.crest.org/

From E.Moerman at stud.tue.nl Mon Mar 11 16:12:43 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:50 2004
Subject: Stoves back online
Message-ID: <80029.s335192@popserver.tue.nl>

It looks like the stoves list is back online. I would like to thank Andrew
and all other people from CREST for restoring our list services.

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

From tduke at igc.apc.org Tue Mar 12 02:49:23 1996
From: tduke at igc.apc.org (Thomas Duke)
Date: Tue Aug 31 21:34:50 2004
Subject: More on Fuzzy Logic
Message-ID: <199603051744.JAA12332@igc3.igc.apc.org>

Hi Stove Friends,

Ken of Madison Wisconsin raised a question of need for more light on
Fuzzy logic. So I am including some of that monologue here because I
see it brings to light more of why I feel fuzzy logic has potential
in helping us in our endeavors.

Fuzzy logic enables us to include factors that are usually outside
the scope of traditional math. Things that are not easy to quantify,
so it enables us to be more inclusive in our modeling. Vague
relationships like this: When people make charcoal, then they have a
product to sell. I think this is where the true value of fuzzy logic
lies. In enabling us to be more inclusive in our model making, so I
am pasting my monologue to Ken on the subject here below.

The most popular fuzzy logic book is titled this: "Fuzzy Thinking The
New Science of Fuzzy Logic" by Bart Kosko. Published by hyperion of
New York. Copyright 1993. ISBN 0-7868-8021-X. Bart does a good job of
step by step introduction of the foundational thinking behind fuzzy
logic. The functioning example he gives when he gets to the actual
application is too simple for the principles he is trying to
illustrate. He is aware that his example problem (control of an
airconditioner fan motor speed) is far to simple to illustrate how it
works. So his solution is too complicated for the problem. It takes a
truly complex system with contridictory rules for the thing to spring
to life.

Linear math is not so different then fuzzy logic in the sense that in
linear math we describe relationships (cause and effect). That we
indicate to what degree there is effect caused by changing the input
variables. This is the same in both fuzzy logic and linear math.
Where fuzzy logic shines is where there are feed back loops. where
the network is large enough to be redundant. Where our computers say
this: "cannot solve circular references". Then the net behaves
life-like. A true model of real life.

In the stoves discussion we can look at this in the broadest terms.
Fuzzy logic enables us to include all the variables in a living net.
This includes chemical reactions, relationships to the environment,
variations in the fuel supply, relationships to human beings,
cultural influences, market forces, the history of man's relationship
to energy and so on. The net can be inclusive and manageable at the
same time.

Once we have a neural net developed we can vary the inputs and see
the results. We can test our net in the real world. We can put in
real numbers from the real world, as the variables change we can see
if our results match or come near to the real results.

This is not so much different then linear math. Except in it's
ability to include generalities and guesses. Fuzzy logic provides us
with a philosophy that helps us see that vague numbers are valid
numbers. Then we can include things like human response to new
technology in the formula (net). Things that are not easy to
quantify.

Fuzzy logic enables us to model systems that are outside the bounds
of traditional math. Real world systems that traditional math cannot
address because they are too complex or to vague. With fuzzy logic we
can sometimes solve a problem or create an adequate model with terms
a general as this: "When the sun shines on it, it gets warm".

In the stoves group I am trying to apply the knowledge we have to
present needs of individuals. This includes people here and people in
developing countries. I see it all as one. Here we have farm families
that are suffering because of depressed grain prices. Now the
government is dropping support for grain over a 7 year period. These
families need new ways of managing their land resource. They need new
products they can produce for existing markets. They need new
products they can grow that donot require herbicides and that donot
cause erosion. So I am exploring the renewable energy field and
biomass because energy is an established market and there are biomass
crops that donot require herbicides and donot cause erosion. Further
away there are African families that are suffering for lack of wood
to burn to cook their meal while they make piles of charcoal to sell
in town. These families are wasting all of the energy released in the
production of that charcoal. They are doing this poorly, so much of
the potential charcoal is wasted. They are using bad combustion
technology so there is smoke released into the atmosphere. We find
that they can cook their meal and make their charcoal at the same
time. That they can do this efficently and without much smoke. That
they can raise their standard of living simply by managing their
resoruce of wood better. These families cannot even afford to buy two
used tin-cans to build a stove from, so we are testing stoves they can
make by digging two holes in the ground.

Back at home we are met with a problem that is outside the boundrys
of ordinary math, and it is this: The power companies donot want any
more electricity or energy. They are requried to purchase some at a
low price. This will not do for the farm family, they are needing
good income from a valuable product. Energy is of value and this can
be described in a fuzzy logic neural net. We can include this
relationship in our calculations: "Farmers can grow crops that capture
and store energy, then farmers have something of value (energy) to
sell." "Farmers use energy, then farmers can produce their own
energy."
And so on.

We can build up an inclusive net and then refine our relationship
statements to include to what degree energy is of value and what
amount of energy farmers use and so on. Our math does not have to be
precise, only correct to the limits of the statement, to produce a
functional model. This way we can quickly build up a working model
that sees the relationship of a efficient, clean burning, blue flame
little one kW wood stove to the energy needs, marketable product
needs, of suffering midwestern farm families, and their relationship
to the rest of the world economy.

Fuzzy logic enables us to model the more inclusive system. It does
not break any of the rules of traditional math. It only opens the way
to see total systems functioning in a total universe. So I see it as
extending our vision to be universe wide in our considerations. I see
it as enabling us to see things we could not see before. Like the
potential for the American farmer to grow energy and apply it in new
ways to the needs of persons.

To some degree we put these fuzzy logic nets together in our minds
all the time. so I feel it is not new, that it is our conscious focus
on these nets that is new. That by consciously focusing on these nets
we can refine them, make them more complete and more accurate.

I can hardly wait to see your comments on this one.

Building a fuzzy logic net,

Tom Duke

From E.Moerman at stud.tue.nl Tue Mar 12 06:50:47 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:50 2004
Subject: Anders 11th March.
Message-ID: <46311.s335192@popserver.tue.nl>

Anders,

If you send the email address of Stephen Karekezi to me, I will take care of
adding him to the list.

> Your little piece on the shoulders of giants: I couldnt make this
> quite out. If its ironic, then I want to be the first to

As far as I know, this is an expression used by some well known physicist. I
can't remember who.

> To Etienne: re. pollution from charcoal production.
> Etienne: Are you sure. Charcoal production is done outside,
> while women usually are exposed to it in a closed room.
>
> Anders: Well, Etienne, as far as our monitoring is concerned
> there is no question about it. Below some figures. For women,
> the figures are during cooking time (avg. 4.5 h fo women in
> Lusaka) for charcoal producers (all men) the figure is average
> for 2.5 hours working by the kiln. In the open. Concentrations
> are averages measured by equipment strapped on to the respondents
> (less painful than it seems, they are lightweight).
>
> Particulates, RSP (less 7.2 micrometers), microgrammes/cu.m.
> mean s.e. n
> Women, Lusaka, charcoal 380 31 95
> Women, Lusaka, wood 890 62 89
> Women, Lusaka, electricity 240 21 67
> Charcoal producers, rural Zambia 1400 190 49
>
> Carbon monoxide. Assessment with Draeger diffusion tubes. Same
> procedure as above. (ppm)
> mean s.e. n
> Women, Lusaka, charcoal 13 7.8 98
> Women, Lusaka, wood 8.5 1.1 88
> Women, Lusaka, electricity 2.1 0.6 63
> Charcoal producers, rural Zambia 13 2.5 44
>
> Carbon monoxide levels are not really disturbing from a health
> point of view. The indoor/outdoor distinction is much less rigid
> in Lusaka than e.g. in Europe.

Etienne:
I find these figures very interesting. I would never have expected such a
large difference in favor of women cooking indoors. It also confirms
something that we already measured with the downdraft stove. Although
charcoal stoves do not emit smoke their CO emissions are higher than those
of woodstoves. It is a real silent killer.

I find these exposure data quite interesting. Does anybody else have data
like this? Kirk Smith perhaps?

Etienne
---------------------------------------------
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 Mar 12 06:53:14 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:50 2004
Subject: Anders 11th March.
Message-ID: <46457.s335192@popserver.tue.nl>

Anders,

If you send the email address of Stephen Karekezi to me, I will take care of
adding him to the list.

> Your little piece on the shoulders of giants: I couldnt make this
> quite out. If its ironic, then I want to be the first to

As far as I know, this is an expression used by some well known physicist. I
can't remember who.

I find these exposure data quite interesting. Does anybody else have data
like this? Kirk Smith perhaps?

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

From aellegaard at nn.apc.org Tue Mar 12 10:53:48 1996
From: aellegaard at nn.apc.org (aellegaard@nn.apc.org)
Date: Tue Aug 31 21:34:50 2004
Subject: Anders 11th March.
Message-ID: <199603121657.QAA05940@nn.apc.org>

Anders: I thought it was clear - the figures given make no distinction between
indoor and outdoor cooking. There was none, because outdoor and indoor mix
so much. Also: Thes concentrations are not any cause for concern. What becomes
dangerous is when the stoves are brought into the bedroom in the winter and
used for heating in the night. Then you can talk about silent killing.

From 73002.1213 at compuserve.com Tue Mar 12 11:03:42 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:50 2004
Subject: STOVE TECHNOLOGY TRANSFER
Message-ID: <2.2.32.19960312160424.007412fc@mail.teleport.com>

Stovers all:

Here's a serious question that we should all consider as we move forward toward
an improved stove or stoves.

1) I assume all of us are here because we have a common concern about the
dreadful and wasteful cooking of our clients - 2/3 of the population of the
world.

2) I presume that if we had a stove that was clean, simple, cheap and a quantum
leap better than conventional wood stoves, we would like to transfer the
technology to our clients as quickly as possible.

3) I started to write about "commercialization" of such a stove, but is that an
oxymoron when one wants to encourange people with no money to adopt a new
improved process? Maybe not. Don't underestimate the power of the dollar
(rupee, yen,....) in mobilizing craftsmen/salesmen/promoters/crooks to spread
the technology. Tech Transfer/Commercialization covers this area.

3) As an inventor with some 20 patents, I appreciate the role that patents have
in permitting investors and sponsors to focus on technology transfer. What a
triumph for the Internet if a group came up with a joint patent that could be
licensed to whoever we pleased, but would centralize the knowledge and
technology. See Bourbaki.

I believe we will achieve the specifications of 2) with a gasifier/pyrolysis
type stove. I want to know now what next.

Please comment - or I'll go private.

TOM REED

From JATURNBU at EPRINET.EPRI.COM Tue Mar 12 21:50:15 1996
From: JATURNBU at EPRINET.EPRI.COM (Turnbull, Jane@G&S M)
Date: Tue Aug 31 21:34:50 2004
Subject: Gender Issues
Message-ID: <MSM.JATURNBU.700150180096072FMSM@EPRI.COM>

I just received a copy of a paper by Amita Makan of the Energy for
Development Research Center in Capetown, South Africa from a friend at
IMF, and I'd like to quote a portion of her conclusions.

"As a result of apartheid, two-thirds of the Soputh African population
do not have access to electrcity. The the present electrification drive
under way, domestic energy policy and planning should be more
sophisticated and strategic in its approach to attain equitable and
sustainable development. "Women and men have different roles in society
and therefore different needs. Energy planners should acknowledge that
women's needs extend beyond the household and include community
mangement needs. Energy planning should also recognize the strategic
interest stemming from unequal gender-relations.

Domestic energy policies that aim at sustainability and equity will
remain flawed and ineffectual if they do not put women at the center of
the analysis....a more, holistic, interactive, qualitative approach is
proposed....in a way which complements existing approaches, adding to
the cumulative conception of the complexity of gender, energy and
development."

Guess my thought is the importance of working with persons, not just on
their behalf.
Jane

From E.Moerman at stud.tue.nl Wed Mar 13 14:20:17 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:50 2004
Subject: Gender Issues
Message-ID: <72224.s335192@popserver.tue.nl>

Jane,

I couldn't agree more with your statements on gender issues. Prasad and I
have written a few proposals and are trying to get them financed. We want
to take the user demands into account to the best of our capabilities,
however donors appear to prefer financing a few sociologists and than expect
from us a ready made design that should meet some vague criteria written
down by these sociologists. Now these people are not designers and usually
collect the wrong data. I think this is a serious problem in all design
projects for developing countries. Admittedly the reverse often occurs too;
engineers that design without bothering too much about user demands and
local capabilities.

Does anyone have an idea what to do about this?

I hope to hear some suggestions.

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

From prasad at tn7.phys.tue.nl Wed Mar 13 14:23:02 1996
From: prasad at tn7.phys.tue.nl (prasad)
Date: Tue Aug 31 21:34:50 2004
Subject: STOVE TECHNOLOGY TRANSFER
In-Reply-To: <2.2.32.19960312160424.007412fc@mail.teleport.com>
Message-ID: <9603130858.AA26964@tn7.phys.tue.nl>

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From CKEZAR34 at aol.com Wed Mar 13 17:15:55 1996
From: CKEZAR34 at aol.com (CKEZAR34@aol.com)
Date: Tue Aug 31 21:34:50 2004
Subject: STOVE TECHNOLOGY TRANSFER
Message-ID: <960313172029_245235581@emout09.mail.aol.com>

All

RE: Tech Transfer

Would a patent licence be better than a design handbook to spread the
technology. Perhaps a picture by picture design handbook for those that
could not read or read english. Would an open design handbook scare away
investors where a license would not?
Chuck Kezar

From 73002.1213 at compuserve.com Wed Mar 13 20:44:02 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:51 2004
Subject: Inverted Downdraft Stove Origins
Message-ID: <2.2.32.19960314014444.0074b214@mail.teleport.com>

Stovers all:

Now that work on stoves is "hotting up" : ) I would like to submit a little
history on the original "inverted downdraft" stove. I say original, because a
number of new ideas are joining the initial concept from other people who don't
know the origins (and may not care).

I recently came across an "invention disclosure" that I made in my last few
months at SERI (NREL) in 1985. It described accurately the inverted downdraft
gasifier, more or less as it still stands, and also described a mixer-burner
driven by compressed air. Compressed air not being a standard fixture in
developing villages, I have spent the intervening 11 years working on various
forms of natural convection stove.

On 19 March, 1995 I wrote the following summary of events.
****
CURRENT STATUS OF THE "INVERTED DOWNDRAFT GASIFIER"

I invented the "Inverted Downdraft Gasifier" cooking stove on a trip to South
Africa in 1985 when I became acutely aware of the terrible cooking conditions in
the tribal homelands. In conventional downdraft gasifiers air passes down
through the biomass, and so requires a blower or suction (usually provided by
an engine). In the inverted downdraft mode air passes up through the biomass
charge, meeting a combustion-pyrolysis zone at the top. Combustible gases then
pass out the top and can be mixed with air and burned in a suitable burner. It
can be operated with either natural or forced convection. It is particularly
suitable for cooking with biomass. I have since met a Mr. Tom Taylor of
Albuquerque who makes a large commercial gasifier operating on a similar
principle.

I returned to the Solar Energy Research Institute (SERI, now the National
Renewable Energy Laboratory, NREL) in the Fall of 1985 and built and tested the
first model of the inverted downdraft gasifier in my laboratory there from
coffee cans and refractory cements. The stove gave an intense blue cooking
flame that would be satisfactory for "modern" clean, efficient cooking anywhere
in Third World countries. This work would be remembered by Jim Diebold and John
Scahill, still there and working on fast pyrolysis.

Unfortunately, this laboratory model used compressed air to achieve sufficient
mixing of secondary air with the gas. I then set myself to build a model based
on natural convection, since Third World homes do not typically have compressed
air. I worked on inverted downdraft stoves in my spare time at my home in
Golden after I left SERI and joined the Chemical Engineering Department at the
Colorado School of Mines.

In 1988 I visited a Mr. Fred Hottenroth (10806 Kaylor St. Los Alamitos, CA
90720). I (My son lives nearby in Long Beach). Fred is a maker of innovative
biomass stoves and is also very concerned with Third World problems. I
discussed the inverted downdraft principle with Fred at that time. I purchased
several of his improved woodburning stoves.

When I returned to my laboratory, I modified one of the wood stoves made by
Fred to operate in the "inverted downdraft mode. It burned very steadily and
cleanly, but not with a blue flame, my target of excellence. Later that year on
a trip to Florida with a Mr. Art Krenzel I demonstrated a smaller stove to my
friend and colleague, Dr. Harry LaFontaine, at his home in Miami Florida. I
explained the principles of operation to him and said that we needed to improve
the secondary air mixing for "blue flame" combustion. He didnt think it was
possible. I bet him $1,000 that I could produce a blue flame with natural
convection. At that time he said that he wished to leave the Biomass Energy
Foundation to me, but did nothing about it.

Harry began work on the inverted downdraft gasifier (and even tried to patent
it) without consulting me. He visited me in Golden in 1989 and showed me a new
model he had made. We made tests (with Agua Das), and were very impressed with
the potential of the wood gas stove. I told him about the stoves of Fred
Hottenroth and he then drove his motor home out to Los Alamitos to talk to Fred.
He entered into some business arrangements with Fred that I was not aware of.
Fred now markets a "Gas-I-Fire" stove along with his other excellent stoves. It
is much superior to conventional wood stoves.

In 1991 Harry sent me a paper on the inverted downdraft gasifier. I was not
happy with the paper. It rambled on at great length about the nature of the
cooking problems in Third World countries. It said almost nothing about the
stove and how it worked. It also made efficiency claims which are probably
overly optimistic. I corrected the paper as much as I could and Harry presented
it at IGT "Biomass Symposium" in Washington, D. C. in March 28, 1991.

Harry is a showman - he once owned a circus. He put on a demonstration at that
meeting that was only partially successful and I was somewhat embarrassed
because I did not feel the stove was fully developed and I still do not think
so.
Harry died in Spring 1994 and left the biomass Energy Foundation (a 501-c-3 not
for profit corporation) to me. I am continuing the work to develop a "blue
flame" stove, but If I win the bet, I doubt if Harry will be able to pay up.

In 1994 Dr. Ronal Larson of Golden called me and asked if it were possible to
make charcoal in such a way that the pyrolysis gases could be used for cooking.
One characteristic of the inverted downdraft gasifier is that it produces 20-30%
yield of charcoal which I have always considered a drawback. He argued that the
charcoal could be made and sold by families while doing their cooking. He and I
began work in my laboratory and at his home to develop improved cooking stoves.
We have built a dozen different models and are still working on further
improvements.
I am currently building a "research stove" in which I can measure the air and
gas flows and take the scientific data needed to design an optimum cooking
stove.

I believe this is a true summary of the developments in this field.

Prof. Thomas B. Reed, Dept. of Chemical Engineering, The Colorado School of
Mines, Golden, CO. 80401. 19 March, 1995

****
I hope this summary is useful as we move toward Technology Transfer.

Sincerely, TOM REED

PS Tom Taylor has commercialized his IDD under the name THERMOGENICS and is
actively marketing a novel new gasifier. Steve Brand manages this. More later
on this.

From E.Moerman at stud.tue.nl Thu Mar 14 09:01:42 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: Inverted Downdraft Stove Origins
Message-ID: <54221.s335192@popserver.tue.nl>

Only a single comment this time on Tom Reed's piece which gave a nice
historical overview on the inverted downdraft stove.

Toms's text:
> In conventional downdraft gasifiers
> air passes down through the biomass, and so requires a blower or suction
> (usually provided by an engine). In the inverted downdraft mode air

Comment:
Ussually, yes. But I would like to point out that we have build and tested
downdraft stoves operating on the buoyancy provided by a small chimney
(typical 1m, but less is also no problem) for almost a decade now. All of
this works perfectly and requires no fans, blowers or what have you.

Etienne
---------------------------------------------
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 Mar 14 09:01:50 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: STOVE TECHNOLOGY TRANSFER. 2.
Message-ID: <54228.s335192@popserver.tue.nl>

I was not planning to comment on the patent issue raised by Tom Reed, but
since Chuck gave a reaction with which I agreed I though I should elaborate
on that.

I am not in favor of patents in this field of work (stoves for developing
countries) for the following reasons:
-I thought we were trying to help the very poor in developing countries. A
patent would than increase the price of the stoves developed for them. Is
this morally acceptable?
-A patent would hamper the development of other promising stoves, since
people producing (developing) new stoves should either pay up; pass on costs
to the very poor or try to circumvent the patent. This last attempt will
very likely add to the cost again. Also they would avoid sharing their
results with other designers until they have a patent.
-Already there are problems with patents and copyrights in several
countries around the world. A large number of countries for which we try to
develop stoves are among these. So what is the use of a patent if you
cannot cash in on it?

Although I expect that any patent held in this field will just be ignored, I
still think we should avoid patents in this field in order to help the poor.

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

From larcon at csn.net Thu Mar 14 17:26:29 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:51 2004
Subject: patents, etc.
Message-ID: <Pine.3.89.9603141419.A24515-0100000@teal.csn.net>

Stovers:

As I write, there is 20-25 cm of new snow on the ground and it's
still coming down. I've spent the last week on solar cars and a new
solar organization for Colorado, in case anyone wants to join either
group. Today I will try to get a little caught up on the many great
recent stove communications. First in response to Tom Reed, Tom Duke,
and Chuck Kezar - mostly on patents:

Tom asked if we agreed on

1) "a common concern about the dreadful and wasteful cooking of our
clients - 2/3 of the population of the world" (I do)
and
2).. "if we had a stove that was clean, simple, cheap and a quantum
leap better than conventional wood stoves, we would like to transfer the
technology to our clients as quickly as possible." (I do)
and
3a) " ..wants to encourage people with no money to adopt a new
improved process? " (I do)
and
3b) "..the role that patents have in permitting investors and sponsors to
focus on technology transfer. What a triumph for the Internet if a group
came up with a joint patent that could be licensed to whoever we pleased,
but would centralize the knowledge and technology. See Bourbaki."
(I like the idea of a group patent, but I wish more discussion on
this point; see below. I also doubt that it is a good idea to
centralize knowledge and technology, especially with the strength of this
group. Who is Bourbaki? )

and Tom concluded: "I believe we will achieve the specifications of 2)
with a gasifier/pyrolysis type stove." (I agree on the pyrolysis part -
not the gasifier part - primarily because I see a huge need for better
charcoal production and because charcoal is a highly valued fuel.)
and "I want to know now what next. Please comment - or I'll go
private."

and Chuck Kezar added: "Would a patent license be better than a design
handbook to spread the technology. Perhaps a picture by picture design
handbook for those that could not read or read English. Would an open
design handbook scare away investors where a license would not?"

As a fore-warning, I am not at all sure that I am correct in
the following - in which I believe I am in disagreement with Tom and
Chuck. I hope others with stove introduction experience will chime in.

Clearly, the hopes of making money will drive many people in the
introduction of any new stove design. Clearly also, patents have an
important role in the introduction of many technologies. However, I see
the patent as being mostly for the financial protection of the inventors
and I presume that is not an issue here.

Rather , I believe the issue is whether a license is a potential
valuable investment for the prospective buyer of a stove license. I
think it will not be in most of those countries where an improved stove
will be important, given the existing infrastructures for stove
manufacture and distribution. My experience is that the rural
metalworkers/potters/stove builders are capable of copying almost
anything brought to them and are likely to be so small, poor, and
numerous that it will be both immoral and impossible to enforce a patent
licence. Were I a prospective licensee, I would decline for this reason,
unless the license were spectacularly cheap and I was sure that I could
sell a better product at a lower price than the traditional stove makers
(and I don't think I could - locally made products are spectacularly
cheap in most places we are interested in).

I believe the optimum size of the units and the construction
materials will need to vary for each different culture. Also, there is
lots of room to get around patents by changing some small thing and
getting a local patent. Therefore, I see little likelihood of success in
our group trying to pick successful specific licensees. Rather, I
suggest letting the free market figure out the least cost approach in
each locale.

If there is agreement on the above and the primary motivations
of this group are Tom's 1) and 2), then our discussion should be on how
to best relay the information that would normally be in a patent
license. I think this will best be done by working with governments and
working with them through videos. Perhaps a royalty from some
introducers could be requested as in "share-ware", but I wouldn't look
for much return. And if requested, it should go to some well-known
non-profit group like the UNEP or FAO (to use in further dissemination in
other countries). Obviously, I would hope that these potential
beneficiaries would soon get into this loop - to speed things up.

Finally, I don't believe that our stove group is anywhere near
agreement on Tom's item #2 virtues ("clean, simple, cheap and a quantum
leap better") of either a small "inverted downdraft" gasifying or
charcoal-making stove. However, while we are slowly working that issue
out, I hope that everyone will contribute on their experiences in the
introduction problem and the issues raised by Tom, Chuck and myself
above.

Specifically, I'd like to get others views on:

a. Is successful stove introduction more likely through many
informal sector manufacturers or through larger manufacturers in each
country or through imports?
b. What is the relative importance of cost vs. "modernity"
(higher costs, better finishing, bright colors, fancy packages, etc.)?
c. Should this group be moving towards being a "licensing
board" ?

(Hopefully additional responses coming today, but I sure am moving slowly.)

Regards,

Ron

(p.s. I found Etienne's response on this topic after preparing my
response. I seem to agree with Etiennne, but find the problem wih the
license, not with the patent.)

From E.Moerman at stud.tue.nl Thu Mar 14 19:39:24 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: Fw: Re: your mail
Message-ID: <6056.s335192@popserver.tue.nl>

------------------------------
From: Thomas Reed <73002.1213@compuserve.com>
14 Mar 96 09:01:32 EST
To: prasad <prasad@tn7.phys.tue.nl>
Cc: "Baldwin, Sam" <baldwins@tcplink.nrel.gov>,
"S. C. Bhattacharya" <bhatta@ait.ac.th>,
"Bryden, Ken" <bryden@cae.wisc.edu>, "Duke, Tom" <tduke@igc.apc.org>,
"Larson, Ron" <larcon@csn.org>, "Miles, Tom" <tmiles@teleport.com>,
"Moerman, Etienne" <E.Moerman@stud.tue.nl>,
"Smith, Kirk" <krksmith@uclink4.berkeley.edu>,
"Verhaart, Piet" <Peter_Verhaart@msn.com>,
"West, Ron" <westr@magellan.colorado.edu>
Subject: Re: your mail

PRASAD:

Glad to learn about your journal. I might be able to afford the $70/yr - no
senior discount?

How about an E-mail version so we can read it better, store it better and
retrieve it better.

I have specialized in small gasifiers. I built a 1in diameter quartz gasifier
for Tom Milne in 1985 that we ran both updraft and inverted downdraft so he
could measure the componenets in the vapor. I have been testing a 4 in diameter
"coffee cooker" gasifier, burns about 30 min and great for making coffee.
Present tests are on a 5 inch diameter, suitable for cooking 20-40 minutes.

What has Jain made?

Regards
TOM REED
---------------------------------------------
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 Mar 14 19:39:55 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: Fw: Re: Linking Environmental Policy With Energy And Tax Policy
Message-ID: <6059.s335192@popserver.tue.nl>

------------------------------
From: Thomas Reed <73002.1213@compuserve.com>
14 Mar 96 09:01:40 EST
To: Folke Bohlin <folke.bohlin@sims.slu.se>
Cc: "Baldwin, Sam" <baldwins@tcplink.nrel.gov>,
"S. C. Bhattacharya" <bhatta@ait.ac.th>,
BIOENERGY <bioenergy@crest.org>, "Bryden, Ken" <bryden@cae.wisc.edu>,
"Duke, Tom" <tduke@igc.apc.org>, "Larson, Ron" <larcon@csn.org>,
"Miles, Tom" <tmiles@teleport.com>,
"Moerman, Etienne" <E.Moerman@stud.tue.nl>,
"Smith, Kirk" <krksmith@uclink4.berkeley.edu>,
"Verhaart, Piet" <Peter_Verhaart@msn.com>,
"West, Ron" <westr@magellan.colorado.edu>
Subject: Re: Linking Environmental Policy With Energy And Tax Policy

Dear Folke:

I have enjoyed your recent letters on sustainability, and will reply in more
detail.

I am sorry to see that you and most on the network have swallowed completely the
somewhat naive arguments on "global warming". I accept that sufficient extra
CO2 in the atmosphere could cause major global changes. So what's new? The
global warmers neglect the fact that

1) We are in an interglacial stage atypical of the climate over the last several
million years. We could inadvertanly be staving off the next glacial age. When
the climate models can be run backward to predict the previous glacial ages,
I'll be more willing to let them be run forward to determine my future and that
of the other 5 billion lemmings here.

2) It seems quite likely that we have had 1C warming this century. However, we
don't have a static baseline. The global temperature has changed more than that
in a number of previous centuries.

3) The globe has been cooling at a steady pacefor the last 200 million years,
storing more and more carbon and hydrogen under ground. Maybe we were meant to
put it back in the atmosphere where it does more good. We can't rely on fossil
fuels very long; when it is gone or becomes clearly demonstrably too expensive
in dollars or environmental changes we will all be using biomass and other
renewable energy.

4) The main lemming pack has been bemoaning CLIMATE (long term) change and
ignoring WEATHER (short term) change. We have been demonstrably having more
cold and hot and wind and water extremes of weather. Possibly this is due to
the enormous heat release bubbles over the major population centers in the
Northern Hemisphere. Does anyone know if the increase of floods and hurricanes
that we observe is observed equally South of the equator?

Any other non-lemmings out there?

Warmest regards,
TOM REED
---------------------------------------------
Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From larcon at csn.net Thu Mar 14 20:39:11 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:51 2004
Subject: ground-based charcoal-making stoves
Message-ID: <Pine.3.89.9603141647.A8229-0100000@teal.csn.net>

Stovers all (but mostly talking to Tom Duke):

This is to add a little more on the suggestion of Tom Duke that
the charcoal-making stove be built into the ground. I will be trying
these ideas as soon as it gets warmer (these ideas for exploration - not
yet recommendations). I apologize for not having a figure for the
following.:

1a. I believe that the wood-containing portion of the hole will need to
be be lined with something in order to prevent cave-ins. A major beauty
of using the earth is that the bottom seal need not be made and this is
the hardest operation for rural craftsmen (at least for my imitation of
them).

b. I think thin sheet metal will work well, but ceramics or
concrete should also - all at low cost. Possibly the ceramics can be
formed and fired in place.

c. The biggest cost saving will come from not having to build in
a lot of structure to achieve mechanical stability and thermal user safety.

d. I wonder if a long pipe will work as the primary air inlet.
I am not concerned about having multiple primary air inlets.

2a. I believe the upper flame-carrying region should be conical rather
than cylindrical, and again should be coated to prevent cave-ins. I
would make this region a double cone - with the inner cone separating
downward traveling secondary air (traveling between the two cones) from
upward traveling inner combustion products. This way the secondary air
can enter circumferentially. "Shims" between the two partial cones
(frustra) will allow control of the secondary air and hopefully will also
allow complete closure of the pyrolyzer when so desired. Note that the
secondary air will be well preheated this way -- for improved efficiency.

b. I found a much improved flame in Ethiopia when I shifted from a
cylindrical to conical upper section, with much more uniform temperature
on the 60 cm flat cook surface. For this application, I believe a cone is
absolutely necessary.

3. In a conversation on this yesterday, Ron West asked whether there
will be sufficient draft to achieve the downward flowing secondary outer
air (and prevent smoke exiting through this region between the cones).
One justification is that the Hottenroth stove design mentioned by Tom
Reed has a region with downward flowing air. Another is the response
given by Etienne to Tom Reed about the natural-draft down-draft stove
developed at Eindhoven. But perhaps the best is the excellent work by
Lord Rumford mentioned by Tom Reed. I happened almost that same day to
read the December 1994 issue of Smithsonian magazine (because it contains
a nice article also on masks, which my wife and I collect), which
contained a background article on Lord Rumford. Specifically it
contained (without comment) a diagram on chimneys showing both upward and
downward-flowing air in the same space and his invention of a shelf to
prevent backflow. (Incidentally does anyone know of a good comprehensive
reference on the chimney, preferably containing experimental and
theoretical results? None of the heat transfer texts I have even mention
the chimney.)

4. As another aside, Ron West is working on the amount of primary air
needed for charcoal-making and gasifying stoves. Modifying Tom Reed's
basic combustion formula "shows" that you need no primary air for a
charcoal-maker with 25% conversion efficiency (enough Oxygen already in
the wood), but Ron is working on the amount of primary air needed to get
up to the required temperature. We find about 1/2 of the initial carbon
atoms remain after pyrolysis, with a 25% conversion efficiency.

5a. I believe the conical upper shape will allow a good match to any
cookpot. Getting the right spacing can be done with shims again.

b. Getting an optimal spacing (1-2 cm?) for the vertically rising gases
can be achieved with a supplementary cylindrical shield matched to each
specific pot.

c. The same or similar cookpot can possibly be used to snuff out the
pyrolysis process when the shims (both inner and outer) are removed. I
hope that one doesn't have to use tongs or other technique to remove hot
charcoal.

d. I have a gut feeling that conical pots will eventually prove to be
the best cookpot shape to use, eliminating the need for the cylindrical
shield of 5b).

e. A semi-circle when rolled up will give a conical half-angle of 30
degrees - which seems like a good standard cone angle.

Regards to all

Ron

From bryden at cae.wisc.edu Fri Mar 15 07:07:56 1996
From: bryden at cae.wisc.edu (ken bryden)
Date: Tue Aug 31 21:34:51 2004
Subject: your mail
Message-ID: <199603150309.VAA85237@audumla.students.wisc.edu>

Stovers all,

Help, I think I must be missing some incoming mail. What journal?
>
>PRASAD:
>
>Glad to learn about your journal. I might be able to afford the $70/yr - no
>senior discount?
>
>How about an E-mail version so we can read it better, store it better and
>retrieve it better.
>

Same comment, what letters on sustainability?

>Dear Folke:
>
>I have enjoyed your recent letters on sustainability, and will reply in more
>detail.

And Tom Reed, as regards global warming I'm with you. But I (and I'm sure
you also) am also certain that biomass energy has a place in our energy plan.

Mark Bryden
bryden@cae.wisc.edu

From prasad at tn7.phys.tue.nl Fri Mar 15 08:52:25 1996
From: prasad at tn7.phys.tue.nl (prasad)
Date: Tue Aug 31 21:34:51 2004
Subject: patents, etc.
In-Reply-To: <Pine.3.89.9603141419.A24515-0100000@teal.csn.net>
Message-ID: <9603151347.AA00416@tn7.phys.tue.nl>

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From RURALNET at delphi.com Sat Mar 16 10:40:31 1996
From: RURALNET at delphi.com (RURALNET@delphi.com)
Date: Tue Aug 31 21:34:51 2004
Subject: Stove Commercialization
Message-ID: <01I2EJG4VTOY986RIF@delphi.com>

Ron Larson introduced me to this list several months ago and I
have been following the technical discussions as much as
possible (being a non-technical type) but did not feel that I
could add any useful comments. However, with the discussions
now expanded to issues of commercialization, I am on firmer
ground and feel I can add some pertinent comments.

Just as a quick background, my company helps set up joint
ventures (JV's) to assemble and distribute stand-alone
renewable-energy systems for rural applications. We currently
have JV's in the Philippines, Botswana and South Africa and
will be moving next into Zambia. Part of our JV's activities
involve the local fabrication of charge regulators and light
fixtures, so I am somewhat familiar with the issues of
commercializing locally made components.

Based on my experience, I agree that patenting the stove
technology will prove difficult if not impossible in the
countries where it is most needed, mainly for the reasons
already outlined by Ron, Prasad, etc. However, some type of
competitive advantage needs to be held by the local company or
companies producing and selling these stoves in order for them
and their investors to see the potential for a profitable
operation and therefore consider investing money and resources.
The obvious advantages will be price (based on being able to
reach production-run levels), quality and a local distribution
and service network. The ability to achieve these advantages
in turn will depend on the local operation being able secure
the necessary capital and technical support, which in many of
these countries will not be found locally (at least not until
the product has proven marketable).

I would be willing to introduce the stove design to our local
JV's since they are typically dealing with a market that should
have an interest in these stoves and its not really a stretch,
either technically or from a marketing standpoint, to consider
it a logical expansion of their product line. If they can get
some demonstration systems in the field, they can gauge local
interest. However, two things I am not sure about:

1. Is there a stove design that is ready to be prototyped and
brought into the field for demonstration purposes? As I'm sure
most everyone on this lists knows, it's important that the
demonstration stoves work properly.

2. Are the technicians on this list who are actually developing
the stove designs looking to control their rights to the
designs? If so, are they interested in becoming involved in
the commercialization of their designs (both from a technical
and financial standpoint)?

Hope this helps.

Ross Losch
Solar Resources
Internet: rlosch@solres.com

From E.Moerman at stud.tue.nl Sat Mar 16 11:48:14 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: char stove: ground-based charcoal-making stoves
Message-ID: <64154.s335192@popserver.tue.nl>

A few days ago Ron L. wrote:

> 1a. I believe that the wood-containing portion of the hole will need to
> be be lined with something in order to prevent cave-ins. A major beauty
>
> b. I think thin sheet metal will work well, but ceramics or
> concrete should also - all at low cost. Possibly the ceramics can be
> formed and fired in place.

Etienne- I have heard good stories about mud. Stick it up the wall smear it
out and fire the stove. If cracks occur smear some mud over the cracks.

Ron L.-
> b. I found a much improved flame in Ethiopia when I shifted from a
> cylindrical to conical upper section, with much more uniform temperature
> on the 60 cm flat cook surface. For this application, I believe a cone is
> absolutely necessary.

Etienne- Interesting, but I don't think anything is absolutely necessary.

> 3. In a conversation on this yesterday, Ron West asked whether there
> will be sufficient draft to achieve the downward flowing secondary outer
> air (and prevent smoke exiting through this region between the cones).
> One justification is that the Hottenroth stove design mentioned by Tom
> Reed has a region with downward flowing air. Another is the response
> given by Etienne to Tom Reed about the natural-draft down-draft stove
> developed at Eindhoven. But perhaps the best is the excellent work by
> Lord Rumford mentioned by Tom Reed. I happened almost that same day to
> ...
> contained (without comment) a diagram on chimneys showing both upward and
> downward-flowing air in the same space and his invention of a shelf to

Etienne- Sometime it can be a little tricky to get the airflow in the right
direction. Probably you will have little or no problem in this case.

Ron L.-
> prevent backflow. (Incidentally does anyone know of a good comprehensive
> reference on the chimney, preferably containing experimental and
> theoretical results? None of the heat transfer texts I have even mention
> the chimney.)

Etienne- Some of our reports contain a bit of text about chimneys. However a
better reference is a book on buoyancy, which is the reason why chimneys
work. One such a book is:

Buoyancy induced flows and transport.
by B. Gebhart, Y. Jaluria, R.L. Mahajan and B. Sammakia.
Published 1988 by Hemisphere publishing corporation.

They discus numerous situation in which buoyancy occurs.
Ron L.-
> b. Getting an optimal spacing (1-2 cm?) for the vertically rising gases
> can be achieved with a supplementary cylindrical shield matched to each
> specific pot.

Etienne- Look at Paul Bussmann's thesis. Gaps slightly over 6 mm. were best
in that case.

Good luck with trying out your ideas.

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

From tmiles at teleport.com Sat Mar 16 11:56:01 1996
From: tmiles at teleport.com (Tom Miles)
Date: Tue Aug 31 21:34:51 2004
Subject: your mail
Message-ID: <2.2.32.19960316165637.0072c368@mail.teleport.com>

The main problem is that some Stovers are addressing messages to copy lists
that do not include everyone on the listserv. Please address messages to:

stoves@crest.org

so that they will distributed to everyone.

Thanks

Tom Miles

At 09:08 PM 3/14/96 -0600, ken bryden wrote:
>Stovers all,
>
>Help, I think I must be missing some incoming mail. What journal?

>
>Mark Bryden
>bryden@cae.wisc.edu
>
>
----------------------------------------------------------------------------
-------
Tom Miles, Jr. Thomas R. Miles
tmiles@teleport.com, tmiles@ortel.org Consulting Design Engineer
http://www.teleport.com/~tmiles/ 5475 SW Arrowwood Lane
Tel (503) 591-1947 Fax (503) 292-2919 Portland, Oregon, USA 97225-1353

From E.Moerman at stud.tue.nl Sat Mar 16 12:09:45 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: Stove Commercialization
Message-ID: <65448.s335192@popserver.tue.nl>

Ross-
> possible (being a non-technical type) but did not feel that I
> could add any useful comments. However, with the discussions
> now expanded to issues of commercialization, I am on firmer
> ground and feel I can add some pertinent comments.

Etienne- You can expand the discussion into any area you want as long as it
has something to do with small-scale (or even medium scale) biomass burning
devices for developing countries. I would specifically welcome discussions
on eg. incinerators, ovens, kilns, institutional stoves, breweries, fish
smoking, etc. Anyway I am glad that we can welcome somebody to the
discussion with experience in the commercial field.

Ross-
> Based on my experience, I agree that patenting the stove
> technology will prove difficult if not impossible in the
> countries where it is most needed, mainly for the reasons
> already outlined by Ron, Prasad, etc. However, some type of
> competitive advantage needs to be held by the local company or
> companies producing and selling these stoves in order for them
> and their investors to see the potential for a profitable
> operation and therefore consider investing money and resources.

Etienne- I don't see how patents can help in this case. They will be pirated
by the competition. Apart from that I agree.

Ross-
> and service network. The ability to achieve these advantages
> in turn will depend on the local operation being able secure
> the necessary capital and technical support, which in many of
> these countries will not be found locally (at least not until
> the product has proven marketable).

Etienne- A lot of countries do have a R&D institute on stoves. However
often they appear not to have the theoretical background required to improve
designs. Also a lot of institutes only promote stoves they developed
themselves even if other stoves are better.

Ross-
> I would be willing to introduce the stove design to our local
> ....
> some demonstration systems in the field, they can gauge local
> interest. However, two things I am not sure about:
>
> 1. Is there a stove design that is ready to be prototyped and
> brought into the field for demonstration purposes? As I'm sure
> most everyone on this lists knows, it's important that the
> demonstration stoves work properly.

Etienne- There are several. However most of them are too cumbersome to use
or hardly reduce the fuel use at all despite of wild claims that are always
made. As far as efficiency is concerned the shielded fire is a good starting
point, although I think at the moment it is still to difficult to use. I
have several ideas for new types and improvements on existing types, however
at the moment I have not the time nor the money to try them.

Ross-
> 2. Are the technicians on this list who are actually developing
> the stove designs looking to control their rights to the
> designs? If so, are they interested in becoming involved in
> the commercialization of their designs (both from a technical
> and financial standpoint)?

Etienne- I not planning on applying for patents (unless somebody convinces
me of the need for it), but I am willing to develop stoves. If you are
interested contact me
privately and we might be able to put together a project. I might be able to
come up with a donor if you are able to involve a lot of local people and
orginazations.

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

From tduke at igc.apc.org Sun Mar 17 09:02:33 1996
From: tduke at igc.apc.org (Thomas Duke)
Date: Tue Aug 31 21:34:51 2004
Subject: char stove: ground-based charcoal-making stoves
Message-ID: <199603171405.GAA23010@igc3.igc.apc.org>

I recieved this this morning and am adding my comments. Tom Duke

> Date: Sat, 16 Mar 1996 17:49:13 +0100 (MET)
> From: "E.Moerman" <E.Moerman@stud.tue.nl>

> A few days ago Ron L. wrote:
>
> > 1a. I believe that the wood-containing portion of the hole will need to
> > be be lined with something in order to prevent cave-ins. A major beauty
> >
> > b. I think thin sheet metal will work well, but ceramics or
> > concrete should also - all at low cost. Possibly the ceramics can be
> > formed and fired in place.
>
> Etienne- I have heard good stories about mud. Stick it up the wall smear it
> out and fire the stove. If cracks occur smear some mud over the cracks.

Tom Duke-
Etienne, I agree. While in India I saw many mud stoves. These were
smeared with new mud when ever cracks appeared. Potters know where to
get good mud. One potter follows mud daubber wasps to find good mud.
So I feel where good mud can be found there will be no problem.

> Ron L.-
> > b. I found a much improved flame in Ethiopia when I shifted from a
> > cylindrical to conical upper section, with much more uniform temperature
> > on the 60 cm flat cook surface. For this application, I believe a cone is
> > absolutely necessary.
>
> Etienne- Interesting, but I don't think anything is absolutely necessary.

Tom Duke- Can you give me an angle for the conical upper section? So
I can make one. Is this an annular conical section? Do we have a ring
of blue flame like Tom Reed is talking about? Or are we needing the
expanding crossectional area to make the stove work?

--------------------------------------------------------------------
Tom Duke
4363 Hunt Road
Burlington, Iowa 52601-8917 U. S. A.
The Renewable Energy Research Center and Farm
--------------------------------------------------------------------

From tduke at igc.apc.org Sun Mar 17 09:02:43 1996
From: tduke at igc.apc.org (Thomas Duke)
Date: Tue Aug 31 21:34:51 2004
Subject: Stove Commercialization
Message-ID: <199603171405.GAA23013@igc3.igc.apc.org>

Very good to see you in the discussion. We are needing your
experience to help us reach needing people. Tom Duke

I am adding some comments below.

> From: RURALNET@delphi.com
> Date: Sat, 16 Mar 1996 10:43:33 -0500 (EST)

> Ron Larson introduced me to this list several months ago and I
> have been following the technical discussions as much as
> possible (being a non-technical type) but did not feel that I
> could add any useful comments. However, with the discussions
> now expanded to issues of commercialization, I am on firmer
> ground and feel I can add some pertinent comments.

> Based on my experience, I agree that patenting the stove
> technology will prove difficult if not impossible in the
> countries where it is most needed, mainly for the reasons
> already outlined by Ron, Prasad, etc. However, some type of
> competitive advantage needs to be held by the local company or
> companies producing and selling these stoves in order for them
> and their investors to see the potential for a profitable
> operation and therefore consider investing money and resources.
> The obvious advantages will be price (based on being able to
> reach production-run levels), quality and a local distribution
> and service network. The ability to achieve these advantages
> in turn will depend on the local operation being able secure
> the necessary capital and technical support, which in many of
> these countries will not be found locally (at least not until
> the product has proven marketable).

Tom Duke-
Innovation is an economic advantage. If the product we provide is
doing a job that they need to have done and want to have done and it
cannot be done any other way easily then they will seek our
product. The product does not need to be hardware. Experience is our
most valuable and easiest to trasnport product. We don't need to make
economic gain the main objective. Orginizations like the Red Cross
prove this point. But more important is this: that we help them (the
people needing the stoves). That we help them develop the attitudes
that enable them to invent their own stoves. That enable them to draw
on our experience as a resource available to them.

Tom Duke-
What works for me with the materials and experience I have probably
will not work for them. So We need to work together with them. We
need their input. We need to have them join us in the development
process. Oak wood works very well for me. Aspen wood doesn't work as
well. The wood they have may not work at all. So we need to design by
combining our experience with theirs.

Tom Duke-
The main thing is helping these people. As I pointed out above the
most important thing we can do is help them develop their attitudes,
so they can invent their own stoves. Other wise we leave them
dependent on us, and they will never be able to make a worthful
contribution. It is very difficult to draw water out of a well that
is empty. These people have no money to give. They have something
that is of much more value then money. They have experience. What we
can learn from them is of more value then money. So I feel that we
need to be looking at this more as a mutual exchange of experience. I
don't think commercialization should be in our thinking. Innovation
is not promoted by commercialization but by meeting needs.

>
> Hope this helps.

Tom Duke-
It realy does help. It helps develop our thinking. I am wanting to
bring other humanitarian groups into this discussion. Churches and
save the children foundations and so on. So we can get more input
from the people in-need.

Tom Duke
4363 Hunt Road
Burlington IA 52601-8917
The Renewable Energy Research Center & Farm (319)754-7384

From tduke at igc.apc.org Sun Mar 17 09:02:59 1996
From: tduke at igc.apc.org (Thomas Duke)
Date: Tue Aug 31 21:34:51 2004
Subject: ground-based charcoal-making stoves
Message-ID: <199603171405.GAA23022@igc3.igc.apc.org>

Hi Ron and Stovers,

I am making some comments below. I sent another message but I am not
sure the stoves@crest.org address got in the to: box. So this may
have a little repetition. Tom Duke

> Date: Thu, 14 Mar 1996 16:21:46 -0700 (MST)
> From: Ronal Larson <larcon@csn.net>

> Stovers all (but mostly talking to Tom Duke):
>
> This is to add a little more on the suggestion of Tom Duke that
> the charcoal-making stove be built into the ground. I will be trying
> these ideas as soon as it gets warmer (these ideas for exploration - not
> yet recommendations). I apologize for not having a figure for the
> following.:
>
> 1a. I believe that the wood-containing portion of the hole will need to
> be be lined with something in order to prevent cave-ins. A major beauty
> of using the earth is that the bottom seal need not be made and this is
> the hardest operation for rural craftsmen (at least for my imitation of
> them).

Tom Duke-
Ron, in India I saw many mud stoves. They usually did what Etinnie
suggested. They plastered more mud to fill the cracks. People that
make pottery know where to get good mud. I have a potter friend that
takes nests of mud daubbers and fires them in the kiln. When one fires
particularly good he follows thoses wasps to find out where they are
getting their mud. Many of the mud stoves I saw in India were build
out of a large block of clay about one meter cubic. I think they had
sticks in them for reinforcing bars. Bamboo was used by Edison for
reinforcing bars in a concrete pool. So I think we can get the
stability they need and easy access for air holes.

> 2a. I believe the upper flame-carrying region should be conical rather
> than cylindrical, and again should be coated to prevent cave-ins. I
> would make this region a double cone - with the inner cone separating
> downward traveling secondary air (traveling between the two cones) from
> upward traveling inner combustion products. This way the secondary air
> can enter circumferentially. "Shims" between the two partial cones
> (frustra) will allow control of the secondary air and hopefully will also
> allow complete closure of the pyrolyzer when so desired. Note that the
> secondary air will be well preheated this way -- for improved efficiency.
>

> e. A semi-circle when rolled up will give a conical half-angle of 30
> degrees - which seems like a good standard cone angle.

Tom Duke-
I plan to try some cones tomorrow. Tetrahedra may be a good bet also.
So I will consider them. Cones allow us to adjust the gap. so these
have appeal. Are you suggesting also an inner cone to constrict the
flame as Tom Reed is doing (constricting)? I plan to try both so we
will know soon.

Jerry Pleasant, an inventor friend of mine that works for Case
Tractor company in experimental discussing the stove says that he
burns oil filters. Discarded oil filters from tractors with a hole
poked in the top burn with a blue flame when standing upside down in
a wood fire. These are cylinders with a metal screen in the center.
The blue flame comes out the center. So I am reminded of the diffuser
that Tom Reed is using.

Tom Duke
4363 Hunt Road
Burlington IA 52601-8917
The Renewable Energy Research Center & Farm (319)754-7384

From E.Moerman at stud.tue.nl Sun Mar 17 12:12:48 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: Fw: Re: Hole in ground-based charcoal-making stoves
Message-ID: <65631.s335192@popserver.tue.nl>

------------------------------
From: Thomas Reed <73002.1213@compuserve.com>
17 Mar 96 08:23:23 EST
To: Ronal Larson <larcon@csn.net>
Cc: "Baldwin, Sam" <baldwins@tcplink.nrel.gov>,
"S. C. Bhattacharya" <bhatta@ait.ac.th>,
"Bryden, Ken" <bryden@cae.wisc.edu>, "Duke, Tom" <tduke@igc.apc.org>,
"Larson, Ron" <larcon@csn.org>, "Miles, Tom" <tmiles@teleport.com>,
"Moerman, Etienne" <E.Moerman@stud.tue.nl>,
"Smith, Kirk" <krksmith@uclink4.berkeley.edu>,
"Verhaart, Piet" <Peter_Verhaart@msn.com>,
"West, Ron" <westr@magellan.colorado.edu>
Subject: Re: Hole in ground-based charcoal-making stoves

Ron Larson, Tom Duke et al:

I certainly wish you luck with the ground based stove. I am sure there are 200
million Africans that also are awaiting results. Some comments:

There are also 2 BILLION Asians waiting for a better stove (10 X ;the number of
clients). They are NOT bone poor, and are very clever with simple metal
working. I'm going for them. My current "blue flame" stove will cost no more
than $10 and will have a turndown ratio of 4.

Extinguishing our stoves to save the charcoal is NOT trivial. My one-rivet flap
valve on the bottom of the can and a piece of sheet metal over the top does the
trick, but I'm too impatient to wait to weigh the charcoal. I use a Windex type
sprayer to cool the bottom of the can. Another major problem for me is to know
the precise moment to cut the primary air. Too soon, and we get a few pieces of
brown partially charred wood. Too late, and we burn charcoal. By watching the
flame I can tell about when - when the fire gets very weak and ready to
extinguish. But I'm not sure I can ask the housewife to do this (while mixing
the bread, tending the baby, ...). I'm thinking of a moist pad under the grate
so that a rush of steam would signal the end of pyrolysis and extinguish the
flame. Any suggestions?

I have reached sufficient smokelessness to operate in my closed lab. The next
hurdle will be to get Vivian to use it in her kitchen. I am also working with
Jute firestarters that will cover the top of the bed and act also as a
distribution plate.

Glad to hear Ron West is thinking about amount of air needed for the pyrolytic
gasification. This requires a knowledge of the "heat for pyrolysis".

Another major problem, Ron West, is that these microdrafts depend on degree of
combustion etc. There is some draft generated by the pyroysis-gasification bed;
there is more generated by the secondary combustion zone, and one needs to know
how they interact. We need to know resistance of fixed beds to gas flow, (the
Ergun equation?). Does anyone know of draft meters that can measure for
instance 0.01 mm of water pressure?
*****
I have in the past had health problems from breathing too much smoke. They
greatly outweight CO problems. BEWARE. Install a fan; work outside; or get
smokeless.
*****
Last week I bought 12 assorted RISER SLEEVES for stove building for $24 -
roughly $2 each;, Denver retail. They are cylinders of vitrous alumina-silicate
used in metal foundries for pouring molten steel and aluminum etc. They are
excellent insulators. I can put my hand (carefully) on the outside of the
gasifier section after a half hour of operation. The burner section is much
hotter, but still well insulated.

They can be cut to any shape with a razor knife. They come in 1/2 and 1 in
increments from 2 1/2 in ID, 3 1/2 in OD to 11 ID X 12 OD. Some are only
suitable for pouring aluminum; the best grade (#3, Joy Mark) can be reused with
molten steel and I have reused many times without degradation. There is also
sold a "rigidizer" of colloidal silica which makes it even harder.

Again, I need to know more about these beauties. I presume they exist in China
and India - and parts of Africa and will be cheaper there. Does anyone know
about riser sleeves out there??

Onward,...... TOM REED
---------------------------------------------
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 Sun Mar 17 15:49:10 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: Fw: Re: Ferrocement for stoves
Message-ID: <78614.s335192@popserver.tue.nl>

------------------------------
From: Thomas Reed <73002.1213@compuserve.com>
17 Mar 96 11:57:02 EST
To: "\"E.Moerman\"" <E.Moerman@stud.tue.nl>
Subject: Re: Ferrocement for stoves

Stovers all:

Along with Etienne's recommendation of mud lining for holes, I need to know more
about the ferrocement initially used in gasifiers (Bob Reines' development?).
What is it, how much does it cost, how hard to cast, what temperatures will its
stand. (How does it compare to the "riser sleeves" I wrote about yesterday?)

Thanks,
TOM REED
---------------------------------------------
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 Sun Mar 17 15:49:24 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: Fw: RE: Stove Commercialization
Message-ID: <78623.s335192@popserver.tue.nl>

------------------------------
From: Thomas Reed <73002.1213@compuserve.com>
17 Mar 96 11:57:07 EST
To: "\"E.Moerman\"" <E.Moerman@stud.tue.nl>
Cc: "Baldwin, Sam" <baldwins@tcplink.nrel.gov>,
"S. C. Bhattacharya" <bhatta@ait.ac.th>,
"Bryden, Ken" <bryden@cae.wisc.edu>, "Duke, Tom" <tduke@igc.apc.org>,
"Larson, Ron" <larcon@csn.org>, "Miles, Tom" <tmiles@teleport.com>,
"Smith, Kirk" <krksmith@uclink4.berkeley.edu>,
"Verhaart, Piet" <Peter_Verhaart@msn.com>,
"West, Ron" <westr@magellan.colorado.edu>
Subject: RE: Stove Commercialization

Etienne, Ross and Stovers:

Thanks for your comments on "commercialization".

It is certainly true that a patent won't carry much weight today in the
countries most needing stoves - China and India (2 billion people); Africa (200
million). However, most of these countries are signatories to the new GATT and
on paper at least are committed to honor intellectural rights. Currently they
are honored by being stolen.

I appreciate what Ross said about needing incentives for local stove makers to
market their stoves and stand behind them, educating the users and improving the
product. So there needs to be some kind of agreement on a particular stove that
crystallizes the improvements and makes evident that an advance has been made.
There needs to be PROFIT for the local stovemaker to propogate the stove or it
won't propogate. And some of this profit may need to trickle back to those in
developed countries to permit them to keep up there interest. So pure altruism
as a motive only motivates a few people and may keep them ineffectual.

So how couold we propogate the perfect stove if we ever develop it? Lets keep
this debate going. I'm just an innocent technologist who recognizes that good
technology is only the beginning.

My best to all, TOM REED
---------------------------------------------
Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From larcon at csn.net Sun Mar 17 20:16:41 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:51 2004
Subject: Response on Stove Commercialization
In-Reply-To: <01I2EJG4VTOY986RIF@delphi.com>
Message-ID: <Pine.3.89.9603171742.A13356-0100000@teal.csn.net>

The following is a highly truncated version of Ross' message with
interspersed responses from Ron Larson

On Sat, 16 Mar 1996 RURALNET@delphi.com wrote:

>
> I would be willing to introduce the stove design to our local
> JV's since they are typically dealing with a market that should
> have an interest in these stoves and its not really a stretch,
> either technically or from a marketing standpoint, to consider
> it a logical expansion of their product line. If they can get
> some demonstration systems in the field, they can gauge local
> interest. However, two things I am not sure about:
>
> 1. Is there a stove design that is ready to be prototyped and
> brought into the field for demonstration purposes? As I'm sure
> most everyone on this lists knows, it's important that the
> demonstration stoves work properly.

Response. I believe this depends greatly on the local
capabilities and the particular stove to be demonstrated. I must
restrict myself only to the charcoal-maker. I only know of 3 persons in
the US who have made and tested one and a few persons in Sudan, Zimbabwe
and Ethiopia who have seen one and helped build one. The best design
locally must reflect local preferences - or it may not be accepted.
However, if the local person understands the basic concept and is willing
to do some experimentation prior to conducting a user demonstration - I
say go for it. Without a local interested stove person, I think it is a
little too early to go directly to a user test.

>
> 2. Are the technicians on this list who are actually developing
> the stove designs looking to control their rights to the
> designs? If so, are they interested in becoming involved in
> the commercialization of their designs (both from a technical
> and financial standpoint)?
>
My guess is that most on this list recognize that it is impossible
to control the rights - virtually any conceivable marketable stove will be
too simple to control. Forgetting your "If so", I also presume that most
are interested in "becoming involved in commercialization" from both
standpoints.

I believe it is quite possible for many to make money from an
improved stove - but they should be prepared to do so with the expectation
that others will be coming in with sufficient modifications and/or lack of
understanding of licenses that they will ignore usual patent protection
concepts.

> Hope this helps.
>
> Ross Losch
> Solar Resources
> Internet: rlosch@solres.com
>

We badly need some demonstrations and I believe you will get the
necessary help - if you believe you have persons willing now to put in
some time working with local materials. Thanks for your input.

Ron Larson

From larcon at csn.net Sun Mar 17 20:58:25 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:51 2004
Subject: char stove: ground-based charcoal-making stoves
In-Reply-To: <199603171405.GAA23010@igc3.igc.apc.org>
Message-ID: <Pine.3.89.9603171831.A14875-0100000@teal.csn.net>

Small comment follows , with much truncation of the original message

On Sun, 17 Mar 1996, Thomas Duke wrote:

>
> Tom Duke- Can you give me an angle for the conical upper section? So
> I can make one. Is this an annular conical section? Do we have a ring
> of blue flame like Tom Reed is talking about? Or are we needing the
> expanding crossectional area to make the stove work?
>
The last line or so of my original message suggested an interior
half angle of 30 degrees, when you start with a semicircular(180 degree)
piece This works out well from my perspective in being able to easily
generate all the dimensions. (The final cone circumferences are the same
as the half-circle "half-circumferences")

Yes it is an annular conical section.

No - not necessarly a ring and only partly blue. Perhaps Tom Reed
can repeat more on how he is achieving a blue flame. The flame is a
"conical" modification of the roughly "cylindrical" flame that I presume
you have been observing. But this depends on whether you are feeding
secondary air into the central part of the flame - in which case you will
have more of a ring. That was the case with the 60 cm disk cooker I was
developing in Ethiopia, starting with a 30 cm dia wood supply

I like the conical section for these reasons:

- it can accomodate a wide range of pot sizes
- it allows a smaller dia wood supply (and it is difficult to get
secondary air to the center of a large wood source)
- it seems to give a more uniform temperature
- it seems like it will allow better control of the secondary air
supply
- it seems like it will better allow final closure to snuff out
the pyrolysis process

(but I don't believe it is a necessity)

Ron Larson

From larcon at csn.net Sun Mar 17 21:11:34 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:51 2004
Subject: Stove Commercialization
In-Reply-To: <199603171405.GAA23013@igc3.igc.apc.org>
Message-ID: <Pine.3.89.9603171912.A14875-0100000@teal.csn.net>

A few comments below:

On Sun, 17 Mar 1996, Thomas Duke wrote:

> Oak wood works very well for me. Aspen wood doesn't work as
> well. The wood they have may not work at all.
>
I do not recall this comment from you before. I have not noticed
any big difference between woods. Could you describe what is happening
with aspen?

> These people have no money to give. They have something
> that is of much more value then money. They have experience. What we
> can learn from them is of more value then money. So I feel that we
> need to be looking at this more as a mutual exchange of experience.

So far I agree.

> I don't think commercialization should be in our thinking. Innovation
> is not promoted by commercialization but by meeting needs.

This part I don't agree with. In some cultures, the stoves are
built on site by the users, but with the charcoal-making stove I believe
there will have to be a few "commercial" components. And I believe that
many cultures and economic strata will prefer to buy in the local market.
Here I think we have to think about "commercialization". Perhaps you can
add a little more on your reluctance to endorse "commercialization". I
think we must certainly avoid thinking that they will ever be free.

Ron Larson

From JATURNBU at EPRINET.EPRI.COM Mon Mar 18 00:51:05 1996
From: JATURNBU at EPRINET.EPRI.COM (Turnbull, Jane@G&S M)
Date: Tue Aug 31 21:34:51 2004
Subject: Please listen to the users!
Message-ID: <MSM.JATURNBU.765552210096077FMSM@EPRI.COM>

You guys are doing a terrific job! I am convinced that you will have a
truly great product. But will the product have a market? I talked with
Ruihong Zhang, a new member of the faculty at U.C. Davis, on Friday and
mentioned this server. Ruihong grew up in northern China where the need
for good stoves was great. She said that in her community the kitchen
was separated from the bedroom, but the stove was adjacent to the bed in
the bedroom so that the waste heat from the stove could warm the bed.
Pollution was the norm. They didn't have extra fuel for heating. I have
asked Ruihong to respond to some of your suggestions to test their
applicability.
Jane

From larcon at csn.net Mon Mar 18 14:00:16 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:51 2004
Subject: Stove Commercialization
In-Reply-To: <960318164208_73002.1213_FHM73-8@CompuServe.COM>
Message-ID: <Pine.3.89.9603181135.A23423-0100000@teal.csn.net>

2 clarifications below.

On 18 Mar 1996, Thomas Reed wrote:

> Dear Ron, Tom Duke et al:
>
> 1) Aspen vs Oak: On a mass basis Aspen (and other soft hardwoods)and Oak (and
> other dense hardwoods) have the same kJ/kg. On a volume basis, Oak has 40-80%
> more kJ/liter and so a batch fed stove might burn 40-80% longer. . In
> addition, the "hard hardwoods will make a denser charcoal. However, I am
> surprised to see that the aspen charcoal does not "duff" (dust off) much.
>
> 2) "No money to give" = "no hard cash", I presume. You two are oriented to
> Africa and I am sure that hard cash depends on stable government, so won't be
> available. As I mentioned, I'll go for Asia where several billion people are
> upward mobile and probably will have cash.
>
I may have led people to believe (erroeneously) that all of
Africa is a basket case. This is far from the truth. Hard currency is
available everywhere - but sometimes costly by virtue of a black market
in some places. If goods are needed that require dollars, I believe they
will be available in virtually every country in the world. The issue is
the number of people who can afford them - and this depends on their
priorities. If the payback time on an investment is short, you can be
assured they will make the investment. They have a better sense of the
value of a dollar than do we.

> Our job of distribution will lprobably be different in each country. I am glad
> to see that Ron believes suffiently in free enterprise to allow for the
> possibility of small entrepeneurs selling and servicing "the stove". I have put
> out more inquiries, and I hope to write much more on this in a few days.
>
It may be that a mud stove will win out, but I am betting on one
with at least some metal - and the "small entrepreneur" is not a
"possibility" - he/she is a necessity. I guess that about 99% of these
entrepreneurs will have no employees.

> onward...........
> TOM REED
>
>
>
> > These people have no money to give. They have something
> > that is of much more value then money. They have experience. What we
> > can learn from them is of more value then money. So I feel that we
> > need to be looking at this more as a mutual exchange of experience.
>
> So far I agree.
>
> > I don't think commercialization should be in our thinking. Innovation
> > is not promoted by commercialization but by meeting needs.
>
> This part I don't agree with. In some cultures, the stoves are
> built on site by the users, but with the charcoal-making stove I believe
> there will have to be a few "commercial" components. And I believe that
> many cultures and economic strata will prefer to buy in the local market.
> Here I think we have to think about "commercialization". Perhaps you can
> add a little more on your reluctance to endorse "commercialization". I
> think we must certainly avoid thinking that they will ever be free.
>
> Ron Larson
>
>

Tom: If you would address your mail to "stoves", which is the group I
sent my material to, I could cut out more of the redundancy above.

Ron

From RURALNET at delphi.com Mon Mar 18 15:55:45 1996
From: RURALNET at delphi.com (RURALNET@delphi.com)
Date: Tue Aug 31 21:34:51 2004
Subject: Stove Commercialization
Message-ID: <01I2HN1K43C2987451@delphi.com>

Let me throw out one possible model for assisting in the
process of commercializing the stove designs being discussed on
this list.

1. A for-profit company (let's call it Stoves, Inc.) is formed
by interested members (individuals or organizations) of this
list who contribute capital and in turn receive shares in the
company and (hopefully!) derive income from share appreciation
and dividends. Owners of the company who provide working stove
designs could also be paid a royalty by the company (although
see point made in # 3 below).

2. Stoves, Inc. would establish partnerships or joint ventures
with companies or entrepreneurs in developing countries
interested in designing, fabricating and marketing stoves.
Either new companies would be formed or Stoves, Inc. would
invest in existing businesses. Stoves, Inc. primary role in
the relationship besides providing some initial small amount of
capital would be to provide: 1) technical assistance in stove
design and production 2) help develop in conjunction with local
partner a business plan for commercializing stoves and 3) help
source grants for product development/market studies and
debt/equity financing for manufacturing/distribution
activities. The local partner would be responsible for
1)actual prototype stove production based on both Stoves, Inc.
input and most importantly local end-user needs and available
product components 2)producing, marketing, distributing and
servicing products.

3. Stoves, Inc. would share in net revenue derived from sales
by the local company depending on its percentage ownership. I
see this as a cleaner approach than establishing some type of
royalty payment as initial stove designs will likely be changed
to meet local needs, thereby bringing into question the
ownership of final designs.

I will be the first to admit that there are many gaps in what I
have outlined, including what level of initial capitalization
of Stoves, Inc. is needed to make the scheme viable, what would
be the operational makeup of the company, how would we locate
partners (not really all that difficult if we can provide some
initial capitalization). Underpinning all these issues is
whether there is a stove design(s) with which we can start the
process.

I would be interested in comments.

Ross

From E.Moerman at stud.tue.nl Tue Mar 19 09:39:08 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: For-profit company
Message-ID: <56470.s335192@popserver.tue.nl>

I find the suggestions made by Ross on stoves inc. fascinating. This could
indeed be a working concept. Of course there will be details that would
have to be sorted out, but as a whole I think it is a potential win-win
situation.

I am game!

Etienne

PS Of course the capital required depends on the impact you want to make at
the start.
---------------------------------------------
Etienne Moerman E.Moerman@stud.tue.nl
Joh. Buyslaan 71 tel. +31-40-2571491
5652 NJ EINDHOVEN The Netherlands

From SCEDWJB at cardiff.ac.uk Wed Mar 20 06:53:32 1996
From: SCEDWJB at cardiff.ac.uk (DAVID W J BEEDIE)
Date: Tue Aug 31 21:34:51 2004
Subject: Welcome to "stoves"
Message-ID: <F9CB91D9C@nrd1s.cf.ac.uk>

Ron,

> Greetings to the stove list. Etienne and I are the moderators and I
> presume you have subscribed because of Etienne's notice on "bioenergy".

Yes.

> We alternate weeks for responses like this - but feel free to write to
> either of us for background. I am going to send the last two summaries,
> but feel free to ask for more. When you feel comfortable, be sure to
> introduce yourself to the full group (which is a great one of about 20)
>
> Ron
>
>
> ps - Jack - be sure to ask this group about rootfuels - it has come up a
> few times, but there have been no extended discussions of the possible
> need for stove modifications - or ways to optimize for other than wood.
>

Thanks. I'll read the group's exchanges for a while to find out if
I can contribute. By the way, my background is engineering
(various disciplines), and a just-completed PhD on a 200kW biomass
gasifier-combustor air-heater with a simple but effective
primary/secondary air control system - with ideas transferrable I
believe to other batch- loaded systems.

Bye for now. Dave.

*****************************************************
Dr.David Beedie
Division of Mechanical Engineering and Energy Studies
University of Wales, Cardiff
FAX: 01222 874317
Tel. 01222 874000 ext.6876
762197 (home)
*****************************************************

From aellegaard at nn.apc.org Wed Mar 20 07:12:17 1996
From: aellegaard at nn.apc.org (aellegaard@nn.apc.org)
Date: Tue Aug 31 21:34:51 2004
Subject: Welcome to "stoves"
Message-ID: <199603201316.NAA16570@nn.apc.org>

Welcome to the list David.
Youll see it quickly fills your mailbox...
I noticed you have worked on biomass gasification. Since I am working
as a consultant for the Stockholm Environment Institute I recall that we
are about to start a project on "bioelectrification", using (if my memory
serves me) gasifiers as primary movers. Maybe you would be interested to
contact Prof. Bjorn Kjellstrom c/o seihq@nn.apc.org to find out what they
are doing, and, who knows, put them on the best and most recent track.
Kjellstrom has been working on gasification since the 70s, I am sure you
know.
Regards
Anders Ellegard

From 73002.1213 at compuserve.com Wed Mar 20 09:25:25 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:51 2004
Subject: "Stoves" address
Message-ID: <960320142552_73002.1213_FHM57-7@CompuServe.COM>

Tom Miles et al:

I have finally figured out why I had a short list of stovers and everyone else
had a long one. Too long to explain, involves minor glitch of Compuserve and
Internet and Me. My apologies to all who havn't been receiving my notes and
answers.

Thanks for your patience Tom Miles.

Tom Reed

From 73002.1213 at compuserve.com Wed Mar 20 09:26:14 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:51 2004
Subject: Stove Commercialization
Message-ID: <960320142526_73002.1213_FHM57-2@CompuServe.COM>

Ross:

Thank you for your broad comments on commercialization, and thanks to the rest
of you who have so thoughfully replied. I'm keeping a file of the comments and
WHEN WE HAVE A STOVE WE CAN AGREE ON we can discuss these ideas in more detail.

Thanks again, TOM REED

From larcon at csn.net Wed Mar 20 11:37:10 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:51 2004
Subject: Welcome to "stoves"
In-Reply-To: <F9CB91D9C@nrd1s.cf.ac.uk>
Message-ID: <Pine.3.89.9603200901.A29647-0100000@teal.csn.net>

Dave:

Welcome again. Your background sounds just right. A few more
questions below.

On Wed, 20 Mar 1996, DAVID W J BEEDIE wrote:

> (various disciplines), and a just-completed PhD on a 200kW biomass
> gasifier-combustor air-heater with a simple but effective
> primary/secondary air control system - with ideas transferrable I
> believe to other batch- loaded systems.

1. What applications were you shooting for - bakeries? brickmaking, etc?

2. Could you describe the various dimensions, and the batch lifetime.

3. Could you describe the air control system.

4. Have you investigated the possibility of a charcoal by-product for your
combustor?

5. Materials? Costs?

6. Has the thesis been published yet in the open literature?

7. How did you find us?

Regards

Ron

From E.Moerman at stud.tue.nl Wed Mar 20 12:39:01 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: Piet Verhaart
Message-ID: <67263.s335192@popserver.tue.nl>

Maybe some of you have missed the responses of Piet Verhaart. Piet just send
me a fax and I can tell you that he is able to read at least some of the
messages, but he is not able to send anything. He did mention that he has
done a number of experiments and I am looking forward to welcoming him to
the group again and finding out more about his experiments.

Looking forward to Piet Verhaart's constructive comments and good ideas.

To Ron Larson: Ron, I will sent the stoves-digest volumes to Piet until his
internet problems are solved so there is no need for you to do so.

Etienne
---------------------------------------------
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 Wed Mar 20 13:14:00 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: Stove Commercialization: reply to Tom Reed 20-3.
Message-ID: <69357.s335192@popserver.tue.nl>

Tom R. said:
> comments and WHEN WE HAVE A STOVE WE CAN AGREE ON we can discuss these
> ideas in more detail.

Why wait this long. I thing we should pick a few (3?) promising stoves and
start. In the mean time other stoves can be developed, but we should never
wait until we have a (close to) perfect product.

Etienne
---------------------------------------------
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 Wed Mar 20 13:14:02 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:51 2004
Subject: Charcoal making stove: Realistic test results.
Message-ID: <69361.s335192@popserver.tue.nl>

I just remembered something I wanted to write a few days ago.

At the start of this list I heard optimistic results on the turn-down-ratio
that would be achievable with the charcoal making stove (inverse downdraft).
The past few days I noticed that some of you quoted achieved
turn-down-ratios of about 2.5 (max. for the moment). I would like to point
out that I already gave this estimate at the start of the discusion. I know
this sounds like 'I told you so' and of course it is. However why I brought
this up is that I wanted to point out that we should not get carried away
and make overly optimistic and unproven claims. Therefore I would also like
to point out that I think the fuel use for a given amount of food (specific
fuel consumption) for the charcoal making stove in its present form will be
too high to be acceptable (that is if I have a good image of the stove).

Still I wish the people working on this stove every succes, since I see some
interesting properties.

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

From bhatta at ait.ac.th Wed Mar 20 21:18:04 1996
From: bhatta at ait.ac.th (S.C. Bhattacharya)
Date: Tue Aug 31 21:34:52 2004
Subject: Stove Commercialization: reply to Tom Reed 20-3.
In-Reply-To: <69357.s335192@popserver.tue.nl>
Message-ID: <Pine.SOL.3.91.960321083657.26376B-100000@rccsun>

I was on a "Sabbatical leave" from the stoves group for some time and
have not yet finished reading all the daily mails that some one saved for
me in my stoves diskette.

I agree with Etienne's suggestion that we need not wait for the perfect
stove for commercialization/diffusion (C/D) efforts to start. Let us start
now (!) with 2 or 3 designs. I will be happy to spend some time for C/D
as free professional service for the community. The question is - is
there anything to offer?

My feeling is that probably fairly developed designs are available.
However the persons who have developed those (and probably have spent
considerable time) need clear recognition (and compensation?) to be
motivitated to offer their products. I suggest the following course
of action by the stoves group:

1) Call to the developers for declaration of their products (with full
performance details) without necessarily disclosing design details.

2) Discussion in the stoves Group how to recognise the developers.

3) Prepare strategy for dissemination.

Without any concrete line of action we appear to be dissipating much of our
energy in discussions that could be more fruitful otherwise.

-------------------------------------------------------------------
S. C. Bhattacharya Voice : (66-2) 524 5403 (Off)
Professor 524 5913 (Res)
Asian Institute of Technology Fax : (66-2) 524 5439
GPO Box 2754, Bangkok 10501 516 2126
Thailand e-mail: bhatta@ait.ac.th
-------------------------------------------------------------------

> Why wait this long. I thing we should pick a few (3?) promising stoves and
> start. In the mean time other stoves can be developed, but we should never
> wait until we have a (close to) perfect product.
>
> Etienne

From Peter_Verhaart at msn.com Thu Mar 21 05:30:03 1996
From: Peter_Verhaart at msn.com (Peter Verhaart)
Date: Tue Aug 31 21:34:52 2004
Subject: Fuzzy logic
Message-ID: <UPMAIL07.199603211032360399@msn.com>

Piet Verhaart
About Fuzzy Logic
As I understand it, fuzzy logic is the probable way organisms that adapt,
react to stimuli. A neural network consists of signal transmitters with
feedback. The actual process is trial and error, the organism or the network
changes transmitters and feedback and even adds units until the network reacts
to external stimuli apropriately e.g. the organism survives.
My problem is that I can't make the step from the actual network to using
neural networks to solve theoretical problems with woodburning stoves. I can
imagine a stove with lots of sensors and valve actuators, connected to a
neural network. After a shorter or longer time we might see that the stove
does most of the things we wrote down as specs. I understood a neural network
adapts to external stimuli but it does not know how it does it, we get the
system to work but it doesn't tell us how it works, the best it may come up
with is something like a cookbook recipe. Take a spoonfuls of sugar, mix with
flour, add b ml of water, add yeast, stir, wait, knead, put in tin, put tin in
oven, wait and out comes bread but don't ask me how it works.
Can somebody enlighten me?

From Peter_Verhaart at msn.com Thu Mar 21 05:30:16 1996
From: Peter_Verhaart at msn.com (Peter Verhaart)
Date: Tue Aug 31 21:34:52 2004
Subject: E-mail stufup
Message-ID: <UPMAIL07.199603211032320774@msn.com>

Dear Woodstovers,
As I said in a fax to Etienne, all Tom Reed's poltergeists, gremlins and Jinns
are here having a party in my computer or in the Internet servers. I can't get
connected to the CQU and on MSN I can only receive E-mail.
An MSN wizzard suggested recomposing a message and seeing whether it gets
sent. So here goes.

Piet

From Peter_Verhaart at msn.com Thu Mar 21 05:30:03 1996
From: Peter_Verhaart at msn.com (Peter Verhaart)
Date: Tue Aug 31 21:34:52 2004
Subject: E-mail, sent or not sent
Message-ID: <UPMAIL07.199603211032300310@msn.com>

My MSN keeps bugging me with the message "There are still messages in your
'Outbox', do you want to close? Yes No.

Just having sent a message and finding date and time sent on it and not on the
others I became so worried that I will risk annoying the recipients with
repeat messages. So, apologies if the other messages are no news to you. CQU,
my channel of preference, is returning gibberish or cutting me off
unceremoniously so have to use MSN and eat its uninvited crap.

Piet Verhaart

From 73002.1213 at compuserve.com Thu Mar 21 08:08:07 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Close coupled gasifier combustor
Message-ID: <960321130828_73002.1213_FHM57-5@CompuServe.COM>

Dave Beedie:

Since the stoves many of us are discussing are close coupled gasifier
combustors, we would appreciate a few paragraphs on what you developed in your
PhD.

Thanks

TOM REED

From prasad at tn7.phys.tue.nl Thu Mar 21 09:00:43 1996
From: prasad at tn7.phys.tue.nl (prasad)
Date: Tue Aug 31 21:34:52 2004
Subject: Stove Commercialization: reply to Tom Reed 20-3.
In-Reply-To: <Pine.SOL.3.91.960321083657.26376B-100000@rccsun>
Message-ID: <9603211355.AA08265@tn7.phys.tue.nl>

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From SCEDWJB at cardiff.ac.uk Thu Mar 21 09:52:43 1996
From: SCEDWJB at cardiff.ac.uk (DAVID W J BEEDIE)
Date: Tue Aug 31 21:34:52 2004
Subject: Close coupled gasifier combustor
Message-ID: <2A99A660DA@nrd1s.cf.ac.uk>

> Since the stoves many of us are discussing are close coupled gasifier
> combustors, we would appreciate a few paragraphs on what you developed in your
> PhD.
>
> Thanks
>
> TOM REED
>

The Summary of my thesis follows. This is rather a broad overview.
I could also provide more specific details, e.g.the Conclusions, if
you want.

Tom, did you receive the papers I sent you by mail a couple of weeks
ago, on my project and my colleague's gasifer-engine project?

Dave.
____________________________________________________________________
SUMMARY
Carefully implemented technology for the production of energy from
waste biomass has the potential to create local and global benefits,
by turning a disposal problem into a useful resource, in an
environmentally benign and sustainable manner. This thesis describes
research carried out in Cardiff under an EU project which provided
joint funding for Cardiff University and Universiti Teknologi
Malaysia. 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 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 is seen as a great advantage despite
the inevitable reduction in heat output, as there can be no problem
with contamination. There appears to be considerable opportunity for
such a system in rural Malaysia, where agricultural wastes are
plentiful; there is a need to improve upon existing solar and open-
fire-based crop drying systems; there is a desire to eliminate the
costs of diesel fuel or electricity where these energy sources are
currently used, and environmental considerations are of growing
importance. There are also potential niche market applications in
developed countries. The purpose of the research and development in
Cardiff was to develop techniques for analysis, and to characterise
and improve its operation.

The unit is 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.

Work commenced with trials to ascertain typical temperature levels
throughout the system, in order to characterise operation and
establish some baseline operating parameters. The unit was operated
without any automatic control or operator invention - except to
agitate the fuel as deemed necessary. These initial results were not
easy to interpret as the major fluctuations tended to swamp much of
the underlying trend. However they showed that the combustor was
capable of effectively burning out the gases produced by the
gasifier, sometimes producing very low emissions, but there were
considerable departures from optimum performance. In the second
phase of work, flow visualisation was undertaken on a cold model of
the combustion chamber to determine if the flow patterns were
satisfactory. It showed the combustion chamber requires further
development, concentrating on improvement of the flow patterns
associated with the first two air injection stages. This supported
observations made in the final phase of work that good burnout
requires the flame front to be located in the final stage.

In the third phase of work, steady thermal input tests - using a
diesel-fired burner instead of solid fuel - were carried out to
evaluate the thermal response of the system and its steady-state heat
exchange efficiency and heat losses, and to examine the variation of
these quantities with thermal input and overall excess air value.

In the final phase of work, an effective 'intelligent' automatic
control system was implemented, using economical sensors and
actuators, to enable the unit to operate at the optimum conditions
defined in the second and third phases. While developing the control
system, various essential modifications were made to the primary
chamber steelwork with several positive effects:
. reduction of the height of the gas path from gasifier to
combustor, eliminating the back-circulation of secondary air into the
primary chamber;
. restoration of the full grate area and addition of steeply
inclined side-plates to maximise exposure of the fuel to the primary
air and settling of the fuel to aerated grate area;
. addition of an extra air-jet-tube under the grate to provide
forced air when the unit is initially lit in order to encourage
accelerated warm-up.
These measures greatly improved the performance of the unit by
allowing the control system to stabilise the air:fuel ratio such that
the flame front was located in the final stage of the combustion
chamber. The on-line instrumentation was also improved in several
ways, leading to complete evaluation of the gasification/combustion
parameters on a continuous basis. Continuous mass balance quantified
the cyclic variation in the ultimate analysis of the volatilisation
compound, and it was concluded that a significant consequence of the
batch-loading system is the control necessary to regulate the
quantity of gas production over the duration of the fuel cycle, while
the quality of the gas in terms of the stoichiometric reaction
temperature probably varies little.

By regulating the gasifier air supply, the control system controls
the rate of gas production. The overall aim of the control strategy
is to minimise excess air, maximise the combustion temperature and
thus minimise the formation of the pollutants which result from
incomplete combustion, while the predominantly fuel-rich local
mixture ratio prevents excessive NOx formation. The controller thus
maximises burnout and minimises smoke and emissions; it also delivers
an audible warning to alert the operator when reload is necessary,
carefully timed to minimise emissions at this time.

While stabilisation of EXAV reduces the natural variation of thermal
input, complete stabilisation of thermal input does not result under
constant secondary air conditions as cyclic variations occur in both
primary air flow and gasification rate to compensate for the changing
fuel state. Modulation of the secondary air supplies in addition to
the primary air supplies would enable simultaneous control of thermal
input as well as EXAV.

From SCEDWJB at cardiff.ac.uk Thu Mar 21 10:35:05 1996
From: SCEDWJB at cardiff.ac.uk (DAVID W J BEEDIE)
Date: Tue Aug 31 21:34:52 2004
Subject: 200 kW Gasifier-Combustor Air-Heating Unit
Message-ID: <2B4F68297B@nrd1s.cf.ac.uk>

> On Wed, 20 Mar 1996, DAVID W J BEEDIE wrote:
>
> > (various disciplines), and a just-completed PhD on a 200kW biomass
> > gasifier-combustor air-heater with a simple but effective
> > primary/secondary air control system - with ideas transferrable I
> > believe to other batch- loaded systems.
>
> 1. What applications were you shooting for - bakeries? brickmaking, etc?
>
Crop-drying was the driving need. Timber-drying, fish-drying, batik-
making are all possibilities, as is anything else needing hot air.
Commercialisation will target crop-drying initially I imagine.

> 2. Could you describe the various dimensions, and the batch lifetime.
>
The unit weighs perhaps two tons, is 1.5m wide by 2m high by 3m long
very approximately. A batch of 40kg lasts ~1.5 hours at 125kW
average input. The variation up and down will depend on the turndown
ratio which I haven't attempted to determine but is I guess ~50-
200kW, i.e.4hrs-1hr...

> 3. Could you describe the air control system.
>
Proportional control of (natural draught) primary air by a combustion
temperature signal with a butterfly valve; on-off control of
(mechanical draught) secondary air; reload-warning alarm; automatic
shutdown. Implemented in a PC for laboratory development purposes.

> 4. Have you investigated the possibility of a charcoal by-product for your
> combustor?
>
I noticed that wood remaining in a cavity between the fuel support
plate and the main door, a space congruent with the gasification
chamber but not in the flow path of the primary air, turned very
nicely to charcoal. This space could easily be used for this purpose.

> 5. Materials? Costs?
>
Mainly mild steel; the heat exchanger tubes will be higher grade but
this is not yet determined; some of the combustion chamber surfaces
are refractory-lined.
The target of the original proposal was a system costing 8000ECU
(Euros?). The fabrication cost in Malaysia would be a good deal
less I believe. Accurate costings will depend on production rate
which is is a bit early to predict since extensive field trials are
needed first.

> 6. Has the thesis been published yet in the open literature?
>
It's not yet in the University of Wales library, but will be soon.

> 7. How did you find us?
>
I 'surfed the Internet' a bit looking for things Green, came across
SOLSTICE, saw BIOENERGY listed in its on-line introduction and signed
up. STOVES was mentioned by one of the BIOENERGY contributors. Goes
to show that surfing the Net isn't always a complete waste of time.

> Regards
>
> Ron
>

I also posted some other info to the group in response to Tom Reed's
request, about half an hour ago.

Regards, Dave.

From E.Moerman at stud.tue.nl Thu Mar 21 13:38:52 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Stoves: suggested models
Message-ID: <70844.s335192@popserver.tue.nl>

Prasad gave an interesting list with stoves. I think it is a good way to
start. However we should also collect the user requirements and specifically
try to solve these problems. General user requirements can be found in
countless publications and I assume that the contacts Prasad mentioned can
provide us with the bottlenecks of the models in their present form.

I am afraid I have little time to do that now, but I will get more involved
in a later stage when the bottlenecks have to be solved. Of course without
any charge. Now the question is who is willing to check a number of reports
and make a list of user requirements.

Etienne
---------------------------------------------
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 Mar 21 13:39:17 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Charcoal making stove: request for test data
Message-ID: <70841.s335192@popserver.tue.nl>

It looks like I finally managed to get stable solution for all realistic
parameters with my combustion model. However the charcoal yield that a
prelimenary calculation gave me is way off, therefore I request all you
people that are testing the charcoal making stove for information.
I would like to get data on:
-type of wood used (also density if possible)
-moisture content of the wood
-temperature at the place where the pyrolysis occurs
-how much of the charcoal is burning and how fast (color indication:
whitish red, orange, orange red, spots of black showing up)

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

From RURALNET at delphi.com Thu Mar 21 17:12:19 1996
From: RURALNET at delphi.com (RURALNET@delphi.com)
Date: Tue Aug 31 21:34:52 2004
Subject: Stoves: suggested models
Message-ID: <01I2LWLMBSOI95QKH9@delphi.com>

In terms of determining general user requirements and
collecting data on the bottlenecks associated with specific
stoves, I think we leave ourselves open to an impossible task
unless we narrow down the field to one or two stove designs
that we feel are particulary promising and to one or two
countries in which to begin prototype testing and marketing,
since I assume each country or region will have its own unique
user needs and fuel requirements.

I have also been trying to figure out what is the product being
marketed by the commercial organization we may establish. I
don't know if it is actually one or two particular stove
designs because of this need for local design modifications.
Instead, I see the "product" being more technical expertise in
assisting the local partner company in modifying a stove design
to meet the particular needs and realities of the local market.

If this is the case, does it first make sense to decide on one
or two countries to work in, based on such issues as potential
size and need of the local market, previous field
studies/testing done, potential local partner availability, the
availability of donor funding for prototype testing, etc. -
essentially choosing a marekt with the highest probability of
short-term success. Then, once a location and partner are
chosen, developing the best stove for that market.

Ross Losch
Solar Resources

From 73002.1213 at compuserve.com Fri Mar 22 11:30:59 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Stove fuels
Message-ID: <960322144634_73002.1213_FHM35-5@CompuServe.COM>

Tom Miles (and stovers):

This note is specifically to the Tom Mileses of this world, but the answer
should be of interest to all stovers.

The Tom Mileses are the WORLD experts on chipping, (grinding, chopping,.....)
wood and production of straws.
If our stoves are to serve the world, they must accept a variety of fuels. I
have a few questions here.

WOOD FUELS:
For the last year I have been using standardized Aspen chips, approx. 1X1X1/4
inch, kindly supplied by NREL (maybe from Tom?). I use from 0.2 to 0.5 kg in a
30-40 minute run, so a bushel goes a long way. They are running out and
forcing me to examine other options. I went to a nursery the other day to get
chipped wastes - and found that they don't chip, they grind into typically 1X1X4
inch "shards". I will dry these in the sun and try them out. However, I would
like to find a source of "standard" soft and hardwood chips. Is there likely to
be anyone selling them in Denver?

I intend to do more tests with the stick wood (branches) and split wood
(1/2X1/2XStove length)that others have found satisfactory.

OTHER FUELS:
Ron and I tested corn in the gasifier/pyrolyser and insufficient air passes
through it in natural draft. Corn cobs will be quite good. I will try dung.
Other candidates?

TINDER: Starting the stove is not trivial, and, much to Ron Larson's horror, I
usually use a propane torch (very non-third world). Fred Hottenroth markets
Celotex (compressed corn fibers) soaked in wax or oil. Works great, but doesn't
cover the whole area and the fire should spread laterally before it starts down
into the fuel mass.

To solve this I have been trying a coarse jute soaked in wax. I'll let you
know. Ron Larson finds that pine needles make a good starter and it has the
additional advantage that the gases coming from below are distributed uniformly
as they come through the pine needle char. In olden times "tinder" was used
with flint and steel for fire starting. Can any of you suggest other materials
serving the function of simple ignition combined with good gas distribution?

The weather is getting up into the 60s here in Denver so I'm anticipating a good
weekend of testing.

Onward,
TOM REED

From E.Moerman at stud.tue.nl Fri Mar 22 14:02:15 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Stove fuels
Message-ID: <72254.s335192@popserver.tue.nl>

Tom Reed:

Obviously I do not know anybody selling wood chips in Denver, however I have
a few suggestions for other fuels. Rice husk and coffee husk are both
possible, but obviously you will get the same problem as with corn. However
it is possible to make briquettes from rice husk, coffee husk, straw, char,
saw dust, etc. This stuff will do fine as long as you add a little wood, the
amount depends on the briquette you try to burn.

Regarding the use of pine needles as tinder, I think you should remember
that pine needles in most developing countries are more difficult to obtain
than propane burners. I don't know whether you have tried soaking 1 or 2
pieces of wood in kerosene for at least half an hour. I always find this a
convenient method, although I don't use branches for lighting.

Etienne
---------------------------------------------
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 Fri Mar 22 14:02:14 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Stoves: suggested models
Message-ID: <72247.s335192@popserver.tue.nl>

Ross wrote:
> In terms of determining general user requirements and
> collecting data on the bottlenecks associated with specific
> stoves, I think we leave ourselves open to an impossible task
> unless we narrow down the field to one or two stove designs
> that we feel are particulary promising and to one or two
> countries in which to begin prototype testing and marketing,
> since I assume each country or region will have its own unique
> user needs and fuel requirements.

I would like to add:
Of course we should concentrate on 1 or 2 cases. I would prefer to take the
local situation as a starting point and not a specific stove. The stove
should be adapted to the user, not the other way around.

Ross:
> .. does it first make sense to decide on one
> or two countries to work in, based on such issues as potential
> size and need of the local market, previous field
> studies/testing done, potential local partner availability, the
> availability of donor funding for prototype testing, etc. -
> essentially choosing a marekt with the highest probability of
> short-term success. Then, once a location and partner are
> chosen, developing the best stove for that market.

Etienne: I think it would provide a good example to start off with a project
with a high probability of succes.

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

From larcon at csn.net Fri Mar 22 14:12:56 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:52 2004
Subject: Response to Moerman on: Charcoal making stove
In-Reply-To: <70841.s335192@popserver.tue.nl>
Message-ID: <Pine.3.89.9603221127.A23254-0100000@teal.csn.net>

Comments below:

On Thu, 21 Mar 1996, E.Moerman wrote:

> It looks like I finally managed to get stable solution for all realistic
> parameters with my combustion model.

I wonder about the use of "combustion" here. I presume you can
control primary and secondary air in the model? The primary air
should be very small compared to secondary. The exit gases from the
pyrolysis zone should have very little O2.

> However the charcoal yield that a
> prelimenary calculation gave me is way off,

I wonder what this means - too high or too low?

> therefore I request all you
> people that are testing the charcoal making stove for information.
> I would like to get data on:

> -type of wood used (also density if possible).

I have not found any detectible difference and have used both high
density and low density woods. I think straws and very low density woods
will not work. I find it very important to stack the wood pieces
vertically. Dung did not work at all but a gourd root fuel worked well.

> -moisture content of the wood

Tom Reed is experimenting with this now; I have not. My
impression has been that the lowest possible is the best. I certainly
have troubles when the wood feels damp.

> -temperature at the place where the pyrolysis occurs

Sorry, no definitive data. See next.

> -how much of the charcoal is burning and how fast (color indication:
> whitish red, orange, orange red, spots of black showing up)
>
> Etienne

I believe the main charge is never burning - I almost never see
any ash. Even at the very top and very bottom, where it is obvious that
some charcoal has disappeared. Above the pyrolysis zone the charcoal is
black. At that zone, I would say from memory that it is dull red - but
it is of course difficult to see this region and I haven't run a test in a
while. (Too cold). When one looks in the primary air holes, I think one
can be fooled at the end of the run, but the temperature looks quite high
then. Clearly more detailed measurements are needed and Tom Reed is
doing that.

I am delighted to hear that your modeling is going well. My
expectation is that the modeling should show that half the carbon atoms
are left behind and half move on to the secondary air zone - relatively
independent of the wood type and moisture content.

Regards, Ron

From larcon at csn.net Fri Mar 22 14:45:03 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:52 2004
Subject: charcoal-making stove
In-Reply-To: <UPMAIL07.199603220550150608@msn.com>
Message-ID: <Pine.3.89.9603221204.A23254-0100000@teal.csn.net>

Peter:
I thought your letter deserving of going to the full list, so am
responding to all, even though I had started more privately.

On Fri, 22 Mar 1996, Peter Verhaart wrote:

> ----------
> From: Ronal Larson
> Sent: Friday, 22 March 1996 0:06
> To: Peter Verhaart
> Subject: Re: Sunrayce
>
>
> Dear Ron,
>
> You wrote
> Are you still using compressed air?
> Perhaps you can describe the stove dimensions you are working
> with. My first tests were not successful, but the design I sent had few
> problems.
>
> No, I constructed another stove, same dimensions 115 mm inside diameter and
> 300 mm tall, both halves of equal length.

Ron: I presume that both halves are 150 mm? If 300, then I would say
the upper draft might be excessive for this diameter

Bottom (fuel containing part fitted
> with a (patentable, Tom Reed?) valve, putting next to nothing in the way of
> air wishing to enter and capable of being hermetically closed to protect the
> cooling charcoal.

I'd like to hear more about the valve. I find the valve needs to
be almost closed during normal operation, being full open only during
startup.

> I used the insert in the top part and had a period of good burning, I would

Could you repeat what you might have said earlier about
"inserts".

> have put a pan of water on if it had been handy. But it was clear that the
> flaming combustion was very sensitive to almost everything.

I have had a great deal of difficulty with wind also, but
solvable with wind shields - shielding both the top and the secondary air
holes.

> When the flames went out, so nearly did mine,

This is not clear. I find that when the secoondary flame goes
out due to some misuse on my part, that I can usually restart quickly by
a match. Sometimes I can save the match by blowing downward.

>I had picked a windless day, which means the
> wind there is gently envelops the experimenter in dense clouds, making him
> feel like a belated Vietnam protester.

I know just what you mean. Protecting from the wind is critical.

> I had a slit between the stove halves of 4.5 mm

This sounds a tad large for this diameter (which I consider too
small for typical large families.)

> and the good combustion was
> very dependent on the correct setting of the bottom valve.

I'm not sure of your word "good". I find what seems to be
acceptable emissions with a turndown ration of 4-5 (15 minutes- 1.25
hours) and little smoke. What happens on each side of "good" and how
wide is "good".

> This was a 'wild' experiment. I always do that with a stove I have just
> finished.

Me too - I don't think there is any other way.

> I will do more and more responsible experiments in future.
>
> Cheers,
> Piet
>
It sounded responsible to me. I think a first necessity is one
more outer wind shield.

Best of luck

Ron

From larcon at csn.net Fri Mar 22 15:06:42 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:52 2004
Subject: Reply on Stove fuels
In-Reply-To: <960322144634_73002.1213_FHM35-5@CompuServe.COM>
Message-ID: <Pine.3.89.9603221247.A23254-0100000@teal.csn.net>

On 22 Mar 1996, Thomas Reed wrote:

> WOOD FUELS:

When I first got started, I found a surprising amount of good
branches along the highway. My wife got used to me chopping it up and
putting in the trunk.

Then I started mixing in some very un-natural wood shingles -
they are so easy to split and get to the right length that I easily
justify their use at this stage. However, in Ethiopia I had my choice of
different woods (no shingles) all day long - brought by donkey. Sorry
this won't help you, Tom.

> TINDER: Starting the stove is not trivial, and, much to Ron Larson's horror, I
> usually use a propane torch (very non-third world). Fred Hottenroth markets
> Celotex (compressed corn fibers) soaked in wax or oil. Works great, but doesn't
> cover the whole area and the fire should spread laterally before it starts down
> into the fuel mass.
>
> To solve this I have been trying a coarse jute soaked in wax. I'll let you
> know. Ron Larson finds that pine needles make a good starter and it has the
> additional advantage that the gases coming from below are distributed uniformly
> as they come through the pine needle char. In olden times "tinder" was used
> with flint and steel for fire starting. Can any of you suggest other materials
> serving the function of simple ignition combined with good gas distribution?
>
In Ethiopia, my landlady's cook regularly used a small piece of
old tire. She cut them to the right size herself. It was remarkably easy to
light and gave off a lot of heat.

I find pine-needles absolutely perfect. Etienne is correct that
they aren't everywhere, but I'll bet that local women have figured this
out almost everywhere. I will start trying various types of dried weeds next.

Since I had no pine-needles and found rubber tires very
objectionable, I used small pieces of charcoal, and found them to be ideal.

Regards

Ron

From E.Moerman at stud.tue.nl Sat Mar 23 12:13:59 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Charcoal making stove: modeling. Reply to Ron L. 22-3.
Message-ID: <65757.s335192@popserver.tue.nl>

Ron:

At the moment it is not my intention to predict the charcoal yield of the
charcoal making stove. I just need data to determine a number of parameters.
When I get reasonable values for these parameters I can try to predict
charcoal yields.

At the moment my model is a pyrolysis model; I should have avoided the term
combustion model. Since I neglect the char combustion at the moment the best
way to get relevant parameters and test the model appears to be comparison
with data from the charcoal making stove since charcoal combustion in that
case is limited according to all you people who are testing.

At the moment the model is a single particle combustion model and as a
results terms like primary and secondary air supply do not apply. Exit gases
from the pyrolysing particle have (obvioulsy) no O2 at all after a little
while after the start of the pyrolysis.

The charcoal yield; the mass fraction of charcoal after pyrolysis and
virgin wood; that I got was around 65%. Far too high.

I did not yet check the difference between high and low density woods. I
only tested 2 cases and I think there was little difference, however I did
not have a detailed look into this.

My 1rst request:
>> -moisture content of the wood
>>

Ron Larson's reply:
> Tom Reed is experimenting with this now; I have not. My
> impression has been that the lowest possible is the best. I certainly
> have troubles when the wood feels damp.
>
My reply to this:
Again I have not looked into the details of this, but I think the charcoal
yield was not seriously affected by the moisture content (as long as it
stays below some value that depends on the temperature of the fuelbed).
Of course the burning rate is influenced by the moisture content as is the
resulting temperature.

Regarding the temperature:
Ron do you think that about 600 C (875 K) is a reasonable value? I am
looking forward to Tom Reed's measurements.

Ron Larson's comment:
> I am delighted to hear that your modeling is going well. My
> expectation is that the modeling should show that half the carbon atoms
> are left behind and half move on to the secondary air zone - relatively
> independent of the wood type and moisture content.

My reply:
Since the charcoal yield is heavily dependent on the ratios of 2 reaction
rate I can predict about any number I want. However the way to go about this
is to use experiments to obtain estimates for this ratio and try to use this
result in predicting other cases hence my interest in the data of the
charcoal making stove.

Since temperature are slowly increasing again, and I assume some of you will
take up testing again, I wish you all a fruitful testing season.

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

From tduke at igc.apc.org Sat Mar 23 22:36:55 1996
From: tduke at igc.apc.org (Thomas Duke)
Date: Tue Aug 31 21:34:52 2004
Subject: Fire Truck Fumes
Message-ID: <199603240339.TAA10134@igc3.igc.apc.org>

To the Stovers:

Our township has a problem with fumes from diesel fire trucks. You
are the best people in the world associated with combustion. So I am
slipping this concern into our stove discussion.

They start the trucks then get their gear on. They are enveloped in a
cloud of poorly combusted diesel fumes as the trucks warm up. The
fire department wants to purchase filters for the trucks at 8,000
dollars each. The township says this costs too much. So I am opening
this to you for discussion.

Thanks,

Tom
Tom Duke
4363 Hunt Road
Burlington IA 52601-8917
The Renewable Energy Research Center & Farm (319)754-7384

From tduke at igc.apc.org Sat Mar 23 22:37:01 1996
From: tduke at igc.apc.org (Thomas Duke)
Date: Tue Aug 31 21:34:52 2004
Subject: Fuel
Message-ID: <199603240339.TAA10140@igc3.igc.apc.org>

Hi Stovers all:

I have good results with well seasoned Oak. I tried rolled up
magazines. I couldn't keep them lit. So I get better response from
some fuels.

A good clean burning stove may help get rid of some paper products
that would other wise go to the land fill. There is some chance that
the heat energy can be used for something useful. So I see our stove
work as having some potential for solving some problems close to home
also.

Thanks,

Tom
Tom Duke
4363 Hunt Road
Burlington IA 52601-8917
The Renewable Energy Research Center & Farm (319)754-7384

From tduke at igc.apc.org Sat Mar 23 22:37:13 1996
From: tduke at igc.apc.org (Thomas Duke)
Date: Tue Aug 31 21:34:52 2004
Subject: New Stove design?
Message-ID: <199603240339.TAA10152@igc3.igc.apc.org>

Hi Stovers:

I am thinking of testing a new (to me) configuration. Perhaps you
have already done this one. Or have some ideas about it. So I am
posing it here before I give it a try.

A six inch diameter can seven inches tall. The top cut out. The
bottom still in. A grate one inch from bottom. Holes in the side of
the can at bottom. A second can about 3.125 inches dia placed inside
the first can (six inch dia). The second can has no top and no
bottom. The second can (3.125 dia) has holes poked in it. So it is
like another grate, however a cylinderical grate. A lid to cover the
space between the two cans, so we have a central chimney 3.125 inches
dia.

I am planning on placing the wood in the space between the two cans.
Primary and secondary air come through the grate in the bottom of the
six inch diameter can. Primary air flows through the fuel bed between
the two cans. Combustable gasses flow from the fuel bed into the
second can, through the can walls (cylinderical grate). Secondary air
flowing up through the center of the grate in the 6 inch dia can
mixes with the combustable gasses inside the second can. Where a nice
blue flame burns.

This shortens our original stove to 1/2 it's heighth. However retains
a 7 inch tall chimney, in the center of the fuel bed (the small dia
can).

______ _______
| | | |
| | D | |
| | | |
| A | | A |
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
B-|--------------------|
| |
C | |C
| |
----------------------

A= Fuel
B= Grate
C= Air holes in sides
D= Chimney

Hot combustable gasses pass from fuel (A) through holes in chimney
walls (D) into chimney where they burn with a blue flame?

It is very similar to the successfully burning oil filters my friend
uses, so I expect it to work very well. I will let you know what
results I get, so you can use my experience in your work.

Sincerely,

Tom
Tom Duke
4363 Hunt Road
Burlington IA 52601-8917
The Renewable Energy Research Center & Farm (319)754-7384

From E.Moerman at stud.tue.nl Sun Mar 24 09:05:58 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Fire Truck Fumes
Message-ID: <54474.s335192@popserver.tue.nl>

Tom Duke:

I don't see how we can help with diesel fumes emitted by trucks. I think
this subject is so different from our experience that I would refer it to
engine designers. There must be a lot of them around, since that is where
the money is. As I see it the diesel fumes cannot be avoided (although they
can be filtered I suppose) with a cold start. We have the same problem
starting a woodfire.

I am living above a parking lot, so I know how sickening these fumes can be.
I hope you get the problem solved.

Etienne
---------------------------------------------
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 Sun Mar 24 09:06:02 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Fuel
Message-ID: <54478.s335192@popserver.tue.nl>

Tom Duke:

I don't see why you would want to send paper to a landfill, so I also don't
see why you would want to use paper as a fuel. In The Netherlands we have
been collecting paper for about 2 decades to rework it to paper and
cardboard. In Germany they have a similar system. Both are very succesfull,
I do not have detailed numbers but a number that stuck is that well over 70%
(or was it 80%) of paper is collected and reused.

Burning is not the answer to everything.

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

From 73002.1213 at compuserve.com Sun Mar 24 11:30:47 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Charcoal making stove: modeling. Reply to Ron L. 22-3.
Message-ID: <960324163219_73002.1213_FHM67-1@CompuServe.COM>

Ron and Etienne:

I think it highly unlikely that a model can predict the charcoal yield of our
stoves. As long as pyroysis temperatues don't exceed 600C, the Water-gas and
Boudouard reactions are asleep, so char yield = fixed carbon in the coal/biomass
analysis. Other factors affecting the yield are: hardwood vs softwood;
internal catalysts (such as ZnCl2) which favor the charring reactions; pressure
(Antal's patent) which decreases evaporation of the volatiles until they can
form char.

Practical factors in our stove: If I cut off too soon, I get come white or
brown chips which would make char yield seem higher (but volatiles up, char
actually down). If I cut off too late, the char begins to burn and roast the
the remaining char above. Since the flame is due to the volatiles burning, you
can tell when they are gone by the flame dying out. It is important to quench
the stove, cut off ALL air (easiest with a shallow layer of water covering
primary air holes, but no reaching the charcoal) and cover top.

Regards,
TOM REED

From 73002.1213 at compuserve.com Sun Mar 24 11:31:01 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Tinder and Bourbaki
Message-ID: <960324163232_73002.1213_FHM67-5@CompuServe.COM>

Etienne et Alia:

Thanks for the "tinder" comments. As I have passed through life and technology
I have found that the starting of processes is often as complicated as operating
them - and generally ignored until later. (Ir took 30 years after the invention
of the auto to develop the "self-starter".) So our practical stove developments
need to include practical starting.

In the tinder department I believe there are three functions to perform:
1) With a single match get the top of the fuel pile burning uniformly in under a
minute (fire needs to spread laterally)
2) After the tinder has burned it will leave some charcoal. This should not
interfere much with gases rising from below, but a slight uniform resistance
will have the effect of distributing the gases over the output area, making them
more easily accessible for air mixing/combustion. (I generally use a perforated
metal plate to do this, but may not be necessary if the tinder/char does a good
job. That's why I'm trying jute mesh.)
3) The tinder should produce a burst of clean heat to get a good draft going in
the chimney-burner and warm it up (cold chimneys don't "draw".)

Bourbaki: I tossed this out last week hoping that someone would know more that
I do. I believe it is the name of a group of French Mathematicians that worked
so closely together that they didn't want to sort out who did what; they
published under this name. I'll try to find out more. However, I think we are
in the same boat here talking about "the Internet Stove", whatever it happens to
be.

Smokeless TOM REED

From 73002.1213 at compuserve.com Sun Mar 24 11:31:00 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Pyrolysis temperature
Message-ID: <960324163229_73002.1213_FHM67-4@CompuServe.COM>

Hi:

I have recently measured the pyrolysis temperature by inserting a sheathed
thermocouple through an 1/8 in hole in the side of the middle of the stove. For
many minutes after starting it records the raw biomass temeprature; suddenly it
begins to go up at 50 C/min, rising quickly to 600 C. Then, being in the
mainstream of hot gas it may fall 20C until the pyrolysis is done. As soon as
the charcoal starts to burn it again goes up very fast. The signal could be
used to determine when the stove should be turned off - in the lab.

Onward TOM REED

From 73002.1213 at compuserve.com Sun Mar 24 11:30:45 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Stove modelling
Message-ID: <960324163221_73002.1213_FHM67-2@CompuServe.COM>

To Etienne and all modellers:

I am glad to hear that Etienne is working on modelling stoves. I would like to
insert a few comments here for all would-be modellers of stoves and gasifiers.

I have long collected models of gasification and generally been unhappy with
them. I felt that those involved had not sufficient acquantance with the
realities they were working on. In particular, 75% of the models of biomass
gasification copied the models for coal gasification. This is inappropriate,
since the principle problem for coal is converting the >80% fixed carbon to gas,
while the volatiles are generally captured unchanged. In the case of biomass
the 20% fixed carbon is the lesser problem compared to converting the >80%
volatiles to gas; nevertheless the focus was on charcoal gasification, ignoring
the volatiles (see for instance Groeneveld thesis).

A further problem was that papers claiming to "model" gasification typically
studied the ISOTHERMAL kinetics of char gasification. Char gasification is very
endothermic, so passing CO2 and H2O through the charcoal bed cools it
dramatically.

In 1984 I (and M. Graboski and B. Levie) then made a model of our stratified
downdraft gasifier that pleased me and others. It involved two separate stages.
(a) It considered the time required for the "flaming pyrolysis" (flaming
combustion in insufficient air) that occurs in the bed and related the time
required to dimensions and shape of particles. (b) lt predicted time and
distance required for charcoal gasification by the products of (a) based on
known kinetics of charcoal reaction rates. It then predicted necessary
dimensions of gasifier vs gas production. I facetiously called it a "PREDICTIVE
MODEL", since all models are supposed to be predictive, but weren't . (Grover
and Gaur also later published a "Predictive model".)
COMMENTS ON STOVE MODELLING:
I believe that the output of the pyrolytic gasifier (PG) section is easy to
predict as a function of air throughput. However, air throughput depends on
draft. In current stove models the draft in the PG section depends (a) on
porosity of bed; (b) on primary draft port (used for turndown) and (c) on draft
from the chimney-burner. Unless you have a very specific stove in mind, I find
it hard to see how you can make a relative model.

If you find these comments useful so far, I can supply other inputs.

GOOD LUCK MODELLERS ALL TOM REED

From E.Moerman at stud.tue.nl Mon Mar 25 07:21:20 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Fw: Re: microwave water heater
Message-ID: <48187.s335192@popserver.tue.nl>

On another list I found a few messages about microwave power for water
heaters. I thought I would send an example to state the idea to the stoves
list in case somebody is interested.

Etienne
------------------------------
From: Brendan A Niemira <niemirab@PILOT.MSU.EDU>
Sat, 23 Mar 1996 09:25:08 -0500
To: Multiple recipients of list AE <AE@SJSUVM1.bitnet>
Subject: Re: microwave water heater

> What if I were to make a water heater based on microwave technology? What if
> were to obtain a magnetron, modify it to heat water exclusively, and somehow
> anclose it in this huge symetrical, insulated tank where the microwaves can
> bounce around until they are totally absorbed by the water. I hav often
> wondered if the efficiency of this device would outpace a typical gas or
> electric heater. . .
>
> Any comments?

It's my understanding that microwave ovens work by heating the water that is in
food, so they already heat water "exclusively". As far as efficiency... didn't
somebody post something a while ago showing that those little resistive heating
coils one can use for a single cup of water actually consume less power per cup
of water heated than do microwave ovens?

As far as large-scale water heating... this seems an incredibly high-tech
solution to a pretty low-tech problem. Why not use the electricity to make
heat directly via resistive coils (electricity -> heat) instead of via
microwaves (electricity -> induction -> microwaves -> heat). Besides,
magnetrons are expensive to replace, and I find it hard to believe that you
wouldn't have to replace them more frequently than you would have to
repair/replace gas flame nozzles or resistive heating coils.

--
Brendan A. Niemira | Dulce et decorum est, pro scientia mori.
Dept. Botany and Plant Path. | Vi veri veniversum vivus vici.
Michigan State University | Crescat scientia vita excolatur.
niemirab@pilot.msu.edu | *Every* day is Earth Day.
--------------------------------------------------------------------------
"No, actually, I'm not going to buy Windows 95. I use OS/2 Warp." - BAN
re: microwave water heater R
---------------------------------------------
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 Mar 25 07:21:18 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Fw: Microwave water heating
Message-ID: <48191.s335192@popserver.tue.nl>

Another reply to the microwave waterheater. I think this will be the last I
forward.

Etienne
------------------------------
From: Simon Britten <simon_britten@MAIL.TAIT.CO.NZ>
Mon, 25 Mar 1996 09:24:19 +1200
To: Multiple recipients of list AE <AE@SJSUVM1.bitnet>
Subject: Microwave water heating

Sorry in advance for the lack of 'commenting-out' in this reply (oh for a
decent email program...)

MARK SQUIRE <mark.squire@DINUBA.COM> wrote...

Subject: Water heaters

<Snip>

Has anyone noticed how efficient a microwave oven is at heating
water? Or rather, how efficient it could be? Magnetrons can (if I
understand correctly) be tuned to heat water exclusively. Well, at the
moment there are (as far as I know) two flavours of water heaters: Gas,
and electric. From what I understand, the electric water heater is heated
by heating elements, while the gas heater heats it in other obvious ways.
But both ways are costly and inneficieny.

What if I were to make a water heater based on microwave technology?
<snip>
I have often wondered if the efficiency of this device would outpace a
typical gas or electric heater. . .

Any comments?
-----------------reply------------------
Simon speaking now:

This is such great lateral thinking that I hate to pour cold (hot :-) water on
your idea but I don't think it's a starter. I'm a telecommunications
engineer, & know more about microwave transmission than cooking or
water heating, so take this with as many grains of salt as is required:

Microwave ovens run at well below 100% efficiency. If you look at the
label on the back of, say, a 1000W microwave oven, you probably see
that it's power consumption is (say) 2kW ie 2000W ie 50% effieient. I
haven't one to look at right now so the numbers are just guesstimates.

So, a 1kW magnetron on the centre of a water cylinder would ratiate
1kW of microwave energy, which providing it was the right frequency
(approx 2.4 GHz I think), will be absorbed by the water which is thus
heated. However this would requirre 2kW of input power, the 'wasted'
1kW I imagine being lost as heating of the magnetron. This 'wasted' heat
would then be lost to the surrounding water. So for every 2kW in, you
would get 1kW of heating by microwave & 1kW by thermal conduction, ie
100% efficient heating.

By contrast, a cylinder with a 2kW electric element will convert 100% of
it's input power directly to heat - you can't get any more simple or
efficient than that!

Electric hot water cylinders are only inefficient 'cos they loose heat by
virtue of being less than perfectly insulated, not because of how the
water is heated in the first place.

PS Thanks Nick, I received and was able to print your WFW solar closet
paper, no sweat!

Simon
simon_britten@tait.co.nz

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

From prasad at tn7.phys.tue.nl Mon Mar 25 09:45:25 1996
From: prasad at tn7.phys.tue.nl (prasad)
Date: Tue Aug 31 21:34:52 2004
Subject: Stove modelling
In-Reply-To: <960324163221_73002.1213_FHM67-2@CompuServe.COM>
Message-ID: <9603251440.AA12876@tn7.phys.tue.nl>

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From 73002.1213 at compuserve.com Mon Mar 25 11:34:30 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Yes, New Stove design?
Message-ID: <960325163537_73002.1213_FHM68-8@CompuServe.COM>

Dear Tom Duke:

Yes, this is a new design to me. I might even try it if you don't mind. .

It is terribly confusing to try to follow your description and your "morse code"
picture is garbeled by word wrap. You say . "A lid to cover the
space between the two cans, so we have a central chimney 3.125 inches
dia." Does this mean that there is a septum preventing combustion gases exiting
the outer ring? It is also unclear whether the central "internal chimney" can
has unlimited accesss to the air under the grate (in which case, maybe none will
flow to the outer fuel section).

MORE PICTURES:
All of which brings me to the problem of our sending and receiving better
diagrams of our stoves. It is ridiculous for us to use 1000 words to describe a
picture that we can easily draw on our autocad/paintbrush/scanners. My
Compuserve mailer has a command "send file" and allows me to browse my files,
pick one and send it. I have done it to other Compuserve friends (my son in
Long Beach).

But Ron Larson says he can't receive it. Can you send receive? Can anyone out
there?
*****
TOOLS FOR STOVES: I have and use regularly in making my stoves:
Can opener for removing lids
Church Key (beer can opener) for making air holes, legs, spacers,...
Aircraft tin snips for cutting more complex holes
No-name snips that cut a running strip 1/8 in wide from a sheet
Long nose, etc. pliers
Electric drill with wide selection of bits, hole saws etc
28 gauge galvanized flashing and 26 gauge sheet, slightly stiffer
Pop rivets and popper
Nibbler from Radio Shack that starts from a small hole and takes 1/8 in nibbles
to make any other size.

I have just found a new (to me) tool. It puts 45 degree, 1/8 in wide crimps
around the edge of a stove pipe or tin can so that the diameter is reduced a few
% and you can insert a 4 in D, 5 in high can into another to make a 10 in can.

Are there other tools that some of you have found useful? Is there an electric
tin snips? (I tend to cut my hands as the metals curl away from the shears).
*****
I spoke at length to Ron Larson in church yesterday for the first time in 6
months and we exchanged penciled sketches of stoves. Very useful.

We discussed commercialization. I explained Bourbaki and we'll check further.
I suggested that we continue to understand the principles of clean gas stove
combustion and continue to evolve designs (with pictures I hope). From the
designs we will begin to understand the principles. We can then design many
stoves to fit the many occasions of the world's needs. With the net we can
communicate with others out there who are in a position to make tests and get
back to us.

So far, we have accumulated a lost of experience. Ron says I can get digests of
our discussions with "subscribe stoves-digest" sent to majordomo. He says we
are up to No. 6 now. One could go through this treasure trove and begin
selecting out principles.

I see the problem in the world stove design of the 1980s that it attracted many
mechanical engineers trying a potentially infinite number of combinations.
However, very few principles of design emerged to guide future steps. Second
problem is that most thought of wood burning stoves, not wood-gas burning as we
are doing.

Comments? Onward..... TOM REED

From 73002.1213 at compuserve.com Mon Mar 25 11:35:01 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Fire Truck Fume Relief
Message-ID: <960325163527_73002.1213_FHM68-4@CompuServe.COM>

Tom Duke, Etienne et al:

The diesel fumes that we all live with are an aerosol, as follows. The high
boiling diesel liquid (100-300C) is sprayed into the cold engine; some burns
but many droplets don't; the remainer pass out the exhaust.

As anyone interested in gasifiers knows, it is very difficult to filter out
these aerosols since the particles are too small (ie <20 microns) to settle out,
due to Brownian motion. However, there are agglomerating filters containing
glass fibers 1-2 microns in diameter which can intercept and drain the fuel. A
20 u particle approaching a 100 u filter element stays in the gas phase and goes
around. A 20 u particle approaching a 1 u fiber smacks into it, wets it and may
run off. (Gelman filters in the lab intercept down to 0.1 micron and cigarette
smoke passed through comes out invisible.) Still a very efficient agglomerating
filter for a big diesel could be $8,000 in our multi layered distribution
system. I''m passing this on to my co-author filter expert, Agua Das,
(Das@welcomehome.org) for comment.

Here's a possibility: The diesel engine was designed for low grade fuels (and
even coal), so its fumes reflect the impurities of diesel. There are refined
grades of kerosene - and there could be refined grades of kerosene or diesel for
startup - so with a small auxiliary tank one could have an odorless warmup.

Better yet, biodiesel from soy oil or waste cooking oil has a pleasant "french
fry" odor. It is available from Mr. Bill Ayres, 913 599 6911; 800 599 9209; FX
913 599 2121 - Agricultural
Environmental Products; AEP (Kansas City). He works with a large Iowa refiner
of oil to manufacture and distribute Soy-Diesel for many applications.

Can you find out for all of us how much fuel is required to get a diesel engine
up to a temperature where it doesn't smoke? An alternate fuel and fuel tank
could make sense if we are talking a liter or a gallon but not if it is 10 or
100 gallons. I started my methanol converted car in cold weather on propane
torch (1 pt) cylinders all winter.

Onward and preferably upward, TOM REED

From 73002.1213 at compuserve.com Mon Mar 25 11:35:07 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Legislatures vs Energy
Message-ID: <960325163531_73002.1213_FHM68-6@CompuServe.COM>

Re the discussion of Olson and Harry Parker on fossil fuel systems:

About 1910 John D. Rockefeller said that the state of New York had "the finest
legislature that money could buy". It would seem from the discussion now that
the US has the "finest legislature that money can buy".
However, this is not so for world oil and Harry's point is well taken that world
oil prices reflect an unsubsidized view of the "true costs" of oil in a
competitive market. ("True costs" do not include environmental costs, military
costs to protect the sources, replacement cost (ha ha) etc.)

Playing God can get awfully complicated, but the Internet gives a wider data
base to us human gods.
*****
I asked a while ago whether the set of all stovers was included in the set of
all bioenergy recipients, but didn't get an answer. I am addressing this to
both sets. Let me know if you receive it twice. Does majordomo look through
overlapping lists when he sends???

Regards to all,
TOM REED

From E.Moerman at stud.tue.nl Mon Mar 25 14:30:26 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Graphs with email
Message-ID: <70567.s335192@popserver.tue.nl>

Tom Reed,

I am afraid you missed my message last week. Last week I included a
wordperfect 5.1 file. This file contained a graph. I sent this as a test
since I also found it inconvenient talking about stoves instead of sending a
graph.

In my message last week I asked everybody to drop me a line if they were
able to see the graph. So far I have had no reaction at all. So I assumed
that this attempt was not successful, although I did receive the file
correctly.

Again let me know if you:
-received the message
-found the enclosed WP file
-were able to read the WP file
-were able to see the graph.

Etienne
---------------------------------------------
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 Mar 25 14:31:02 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Composition of Bioenergy and Stoves lists
Message-ID: <70570.s335192@popserver.tue.nl>

Tom Reed,

Tom Miles send a message that included part of the answer. In case you
missed that a little more explanation.
No the stove list is not a subset of the bioenergy list. However I think
most if not all people on the stoves list subscribe to the bioenergy list
too. Send "who bioenergy" and " who stoves" to majordomo and you will get a
list of people suscribed to the list. Majordomo doesn't cross check the
bioenergy and stoves lists, they are completely seperate.

Etienne
---------------------------------------------
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 Mar 25 15:10:57 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:52 2004
Subject: Stove modelling not possible?
Message-ID: <76373.s335192@popserver.tue.nl>

I would like to give a small reaction on Prasad's comments on stove
modeling. I think that the situation is not as bad as some of you make us
believe. Details on wood properties are difficult to find, but they are
available. Regarding heat conduction for wood (an anisotropic porous medium)
I refer to:
Principles of wood science and technology I - Solid wood
written by
F.F.P. Kollmann and W. A. Cote, Springer-Verlag Berlin, 1968.
Although dated it is excellent work containing lots of wood properties.
Some modern experimental work could add to the areas that are a bit vague in
this work.

Prasad-
> definition of anisotropy does is to duck this question (at least as far as I
> can gather). The effect of porosity is that there will be aie entrappedin
> these pores and heat transfer by convection and radiation plays a

Etienne-
This is exactly what I am and some others have been modeling.

Prasad-
> Of course there is the chemistry of pyrolysis. It is not at all clear to me
> from what I've read how important is this chemistry in determining the
> outcome of the process. For starters there doesn't seem to be consensus over
> whether the process is exothermic/endothermic. My own feeling is that it
> depends upon the temperature range one finds oneself in. At any rate the
> energy involved in these processes seem to be small compared to the energy

Etienne-
The last few years several experiments have shown that the
endo/exothermicity depends on the prevailing temperature indeed. I suppose
Tom Reed can give details on this, otherwise Di Blasi mentions this point
and gives some reports on it.

Prasad-
> elementary modeling in most of our work. It is not at all clear to me that
> we should attempt much more sophisticated modeling if we remember the lady

Etienne-
If we are serious about the charcoal making stove we should model the
pyrolysis process. While we shouldn't expect wonders it might help us in
advising charge sizes, charge intervals and power output. Of course a lot
can be done without detailed models of the pyrolysis process.

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

From 73002.1213 at compuserve.com Mon Mar 25 22:22:09 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Stove tests
Message-ID: <960326032337_73002.1213_FHM58-1@CompuServe.COM>

Stovers all:

Sometimes it is useful to back up and perform simple tests. STOVE TESTS
This will document some of the stove tests that I have entered in the BIOMASS
GASIFICATION notebook.

3/23/96
TESTS ON 4 in diameter, 5 ? in high pyrolysis/gas stove. This small stove
contains about 90 g aspen chips, generates gas for 15 min and is useful for
short run tests.
A. TESTS WITH VARIOUS CHIMNEY-BURNERS AND AIR GAPS:
Chimney burners for tests: #1: 6"x3 ? in OD riser sleeve; #2 12"x3in riser; #3
12" x 2 ? in riser; #4: 3 1/4X5 in high (dog food) can; #5: 3X5in can (tom
soup?)
The gasifier was fitted with three long screws 1/8 in below rim to support these
various chimneys.

The stove was lit at top with 1 in pine needles as tinder. Did not catch.
(Inadequate, soak in wax or oil.)

Relit with torch fired under chimney #1. Gave rapid start, active flames, no
smoke or odor, but some yellow in all flames today since draft area too large.
Observed that all the above chimneys, held over gas generator would collect all
the gas and burn it fairly well. #1 gave too large a draft and flame, others
less so. When chimneys were removed, there was initially a strong production of
gas and combustion over top area - but slowly dwindled to partial draft and
small coverage.
Stove out of fuel at 14 min - dumped and quenched.

B. AIR GAP :HEIGHT VS TURNDOWN, 3 ? IN CHIMNEY.
Lit through air gap with pine tinder. Again marginal lighting, good fire in 5
min. Held chimney at various heights and it collected flame up to 3 in above
rim. Flame even noisy. Volatiles out a at 11 min. Dumped.
C. TURNDOWN TEST
Torch-lit through gap. Slow to start. Needs waxed tinder to start and generate
high draft ASAP. Flames dropped down to wood surface; requires distributor to
keep at top. Added plate successfully. With 3 ? in chimney, bright yellow
flame. 1/8 in air gap gave hot blue flame on DP. Chimneys #$ & #5 also gave
good draft. Observed wandering blue flame on DP.

3/25/96:
EXPERIMENT SHOWING INVERTED DOWNDRAFT VS UPDRAFT DIFFERENCE
Performed a very simple experiment to determine the difference between Inverted
downdraft (flame on top passing down) and updraft (flame below, heating whole
charge).

Grate placed in bottom of a 3 in D X 5 in can, open bottom and top, clamped in
ring stand. Charged with 100 g dry aspen chips.

INVERTED DOWNDRAFT MODE: Charge lighted on top; after 2 min a gas flame burned
at top rim of can, initially 6 in, up to 8 in as flaming pyrolysis moved down.
No visible smoke between flame and charge in can. At 12 min fire reached grate.
At 15 min volatiles used up and fire out. One minute acrid smoke. Then char
burned another 5 minutes.

UPDRAFT MODE:
Lit bottom of can through grate. Initially a dense white smoke (mostly steam)
came out the top and wouldnt support combustion. After 6 min supported
combustion weakly, then stronger and stronger to 18 in high flame. Dense smoke
visible inside flame. AT 12 min gas inside flame transparent to bed, flame less
luminous, 6 in high. 13 min going out, acrid smoke. 14 min clean burning
charcoal fire. 21 min charcoal burned out.

These are very simple tests, but illuminating if you watch them thoughfully.

TOM REED

From 73002.1213 at compuserve.com Mon Mar 25 22:22:36 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:52 2004
Subject: Stove modelling vs Fiddling
Message-ID: <960326032341_73002.1213_FHM58-2@CompuServe.COM>

Prasad:

Thanks so much for your kind offer of your modelling book. (C.L.Zaror and
D.L.Pyle "The pyrolysis of biomass: A general Review" in WOOD HEAT FOR COOKING
(eds:K.Krishna Prasad and P.Verhaart), Indian Academy of Sciences). So Piet V
was a co-editor. I thought he sounded very knowledgable for an out back Aussie!

Yes, yes, please send. I would be happy to pay all expenses. Should it be
re-published by BEF Press? (I can make copies when yours run out for about $10
each and sell them for $20).

I'm presenting (with Siddhartha Gaur) a paper on the "HEAT FOR PYROLYSIS" at the
upcoming Thermochemical Conversion conference in Banff, and I have written on
this before, so I am fairly up on thermodynamics of pyrolysis.

You are so right that no two measurements of HEAT OF PYROLYSIS (ie, in the
narrow temperature range where the reactions occur, 300-400 C) or HEAT FOR
PYROLYSIS (HEAT OF plus sensible heats to reach pyrolysis temperature) will be
the same. Therefore, we need guidelines to evaluate situations when it it isn't
measurable.

When there is a high yield of charcoal (20-30%) the HEAT OF is exothermic and
Mike Antal has measured /\Hp as a function of char yield. For now I'll say that
the heat FOR slow pyrolysis is 10% (+/-4%) of the heat of combustion. In fast
pyloysis pyrolysis of small particles the char yield is 10% and more heat goes
into vaporization of the wood oil, so heat FOR pyrolysis is more like 20% of the
heat of combustion. I hope to review all this for our Banff paper. (Or better
yet, I hope Sid will.)
*****
You rightly ask whether studying wood pyrolysis amounts to "fiddling while the
forest burns". Yes and no. See my message this morning about Bourbaki. Making
new stove models without understanding the principles of combustion,
gasification and pyrolysis can also stand in the way of progress, and much
earlier stove research was hampered by what I would call a purely empirical
approach. Then there is the mass of graduate students who have done very
accurate work on irrelevant systems.
So ... I am so glad to have Stovers here who are willing both to try new models
and are patient enough to be interested in the principles involved. Maybe the
dual approach will now lead us to the promised land where neither could by
itself.

And I am all for SIMPLE modelling which can be continually compared to
experimental results.

Thanks again for the book offer.

Onward and upward TOM REED

From SCEDWJB at cardiff.ac.uk Tue Mar 26 05:26:17 1996
From: SCEDWJB at cardiff.ac.uk (DAVID W J BEEDIE)
Date: Tue Aug 31 21:34:52 2004
Subject: sending graphics to lists
Message-ID: <1051044328@nrd1s.cf.ac.uk>

Tom,

Regarding your wish to include good graphics with email to the
list(s), please don't ! Not because I wouldn't like to see good
graphics but because my mailbox is very limited in size and receives
about half its capapcity every day due to being on three lists. When
it overflows everything jams up, I miss lots and have to drop
everything to sort it out.

Being in the University gives me access to a standard (~1MB) amount
of resource; also the mail program is only geared for text. Can I
make an alternative suggestion: we ask our list coordinators to
hold graphics images for the list, which can then be accessed on
demand by interested parties by a 'Get ....' instruction to
the Majordomo.

Regards, Dave.

> MORE PICTURES:
> All of which brings me to the problem of our sending and receiving better
> diagrams of our stoves. It is ridiculous for us to use 1000 words to describe a
> picture that we can easily draw on our autocad/paintbrush/scanners. My
> Compuserve mailer has a command "send file" and allows me to browse my files,
> pick one and send it. I have done it to other Compuserve friends (my son in
> Long Beach).
>
> But Ron Larson says he can't receive it. Can you send receive? Can anyone out
> there?
> *****

From larcon at csn.net Tue Mar 26 07:40:22 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:53 2004
Subject: Legislatures vs Energy
In-Reply-To: <960325163531_73002.1213_FHM68-6@CompuServe.COM>
Message-ID: <Pine.3.89.9603260512.A13037-0100000@teal.csn.net>

On 25 Mar 1996, Thomas Reed wrote:

> I asked a while ago whether the set of all stovers was included in the set of
> all bioenergy recipients, but didn't get an answer. I am addressing this to
> both sets. Let me know if you receive it twice. Does majordomo look through
> overlapping lists when he sends???
>

I received both, and guess that most will have also. But there
are about 4-5 on the stove list who are not on the bioenergy list.

Ron

From prasad at tn7.phys.tue.nl Tue Mar 26 07:56:59 1996
From: prasad at tn7.phys.tue.nl (prasad)
Date: Tue Aug 31 21:34:53 2004
Subject: Legislatures vs Energy
In-Reply-To: <Pine.3.89.9603260512.A13037-0100000@teal.csn.net>
Message-ID: <9603261251.AA14308@tn7.phys.tue.nl>

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From E.Moerman at stud.tue.nl Tue Mar 26 08:52:48 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:53 2004
Subject: Graphs
Message-ID: <53577.s335192@popserver.tue.nl>

To all,

It is not possible to send graphs or pictures with the list. However David
came up with a good idea. The moderator can keep the graphs and send them to
people privately if requested. My problem is that my harddisk is almost
full, I cannot keep any phaotographs only a few simple graphs. In a few
weeks time I hope to have sufficient space again. I suggest that everbody
that wants to send a graph or a photograph contact me or Ron Larson, we can
then make arrangements.

I have a WP5.1 file containing a graph of how I think the charcoal making
stove looks like. Anybody interested? Size about 60Kb.

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

From aellegaard at nn.apc.org Tue Mar 26 11:05:03 1996
From: aellegaard at nn.apc.org (aellegaard@nn.apc.org)
Date: Tue Aug 31 21:34:53 2004
Subject: Graphs
Message-ID: <199603261708.RAA26373@nn.apc.org>

Dear Etienne,
That sounds interesting. I have always wanted to know how this stove looks.
I didnt think anybody but me was still using WP51! So how shall we proceed?
Anders

From tmiles at teleport.com Tue Mar 26 11:38:49 1996
From: tmiles at teleport.com (Tom Miles)
Date: Tue Aug 31 21:34:53 2004
Subject: Graphs
Message-ID: <2.2.32.19960326162249.008e16dc@mail.teleport.com>

Etienne et al,

Send your graphic images to one of the moderators:
Etienne Moerman E.Moerman@stud.tue.nl
Ronal Larson larcon@csn.net
Tom Miles tmiles@teleport.com

We will send them to CREST to put in the list archive. They can be retrieved
by sending a message to Majordomo@crest.org with the command

get stoves filename.extension (in lower case)

A list of the files in the archive can be retrieved at anytime by using the
command (again to Majordomo)

index stoves

Just this week a graduate student in Thailand retrieved a file from the
bioenergy archive and found it useful for his research. It is in PDF (Adobe
Acrobat) format which is useful for viewing and printing from either Mac and
Windows.

We can also post graphics on public web sites. I'll offer mine for posting,
or we can probably create a "Stoves Laboratory" site at CREST.

We have the tools. It's just a matter of using them efficiently.

Thanks for your cooperation.

Tom Miles

At 02:52 PM 3/26/96 +0100, E.Moerman wrote:
>To all,
>
>It is not possible to send graphs or pictures with the list. However David
>came up with a good idea. The moderator can keep the graphs and send them to
>people privately if requested. My problem is that my harddisk is almost
>full, I cannot keep any phaotographs only a few simple graphs. In a few
>weeks time I hope to have sufficient space again. I suggest that everbody
>that wants to send a graph or a photograph contact me or Ron Larson, we can
>then make arrangements.
>
>I have a WP5.1 file containing a graph of how I think the charcoal making
>stove looks like. Anybody interested? Size about 60Kb.
>
>Etienne
>---------------------------------------------
>Etienne Moerman E.Moerman@stud.tue.nl
>Joh. Buyslaan 71 tel. +31-40-2571491
>5652 NJ EINDHOVEN The Netherlands
>
>
----------------------------------------------------------------------------
-------
Tom Miles, Jr. Thomas R. Miles
tmiles@teleport.com, tmiles@ortel.org Consulting Design Engineer
http://www.teleport.com/~tmiles/ 5475 SW Arrowwood Lane
Tel (503) 591-1947 Fax (503) 292-2919 Portland, Oregon, USA 97225-1353

From CKEZAR34 at aol.com Tue Mar 26 18:48:34 1996
From: CKEZAR34 at aol.com (CKEZAR34@aol.com)
Date: Tue Aug 31 21:34:53 2004
Subject: Fire Truck Fumes 2
Message-ID: <960326185158_256693641@emout09.mail.aol.com>

RE: Diesel Fumes
During Desert Storm the Army had to use sulfur-free diesel fuel for a period
of time because there was no other fuel. The lack of sulfur ruined the fuel
pumps as the sulfur acted as a lubricant, but the normal black smoke from the
diesels was missing. It seems the soot particles form around the sulfur
molecule. I suggest contacting the Army or DOE fuels people who are
examining this situation. The solution is not simple because diesel fuels
need a lubricant and if not sulfur what? But a fuel shift might be better
than other solutions. This may not solve the air polution problem, but it
may reduce the black smoke. Possible contacts for the latest in this
research area are: Army Research Office PO Box 12211 Research Triangle
Park, NC 27709-2211 or <AMXRO_D@ARO-EMH1.ARMY.MIL> Possible point of contact
Dr. A. Crowson 991-549-4261 (Material Sciences Division) or call HQ Army
Research SARD-ZT Ms. Sharron Vannucci FAX 703-695-3600 Phone: 703-697-8432
and ask her for the Army expert in this area. Use my name with Sharron.
Regards, Chuck Kezar

From bhatta at ait.ac.th Wed Mar 27 06:58:12 1996
From: bhatta at ait.ac.th (S.C. Bhattacharya)
Date: Tue Aug 31 21:34:53 2004
Subject: No Subject
In-Reply-To: <53577.s335192@popserver.tue.nl>
Message-ID: <Pine.SOL.3.91.960327073944.12230B-100000@rccsun>

Yes, I am interested in your Figure (Graph?) of Charcoal making stove.

S.C. Bhattacharya

On Tue, 26 Mar 1996, E.Moerman wrote:

> I have a WP5.1 file containing a graph of how I think the charcoal making
> stove looks like. Anybody interested? Size about 60Kb.
>
> Etienne
> ---------------------------------------------
> 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 Wed Mar 27 08:16:21 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:53 2004
Subject: Fw: Re: Water heaters
Message-ID: <51497.s335192@popserver.tue.nl>

A possibility for diesel fume reduction?

Etienne
------------------------------
From: Alan Muller <amuller@DCA.NET>
Tue, 26 Mar 1996 21:56:10 -0500
To: Multiple recipients of list AE <AE@SJSUVM1.bitnet>
Subject: Re: Water heaters

>
>By the way, you are not alone in thinking about microwaves in appliances
>other than ovens. I have seen a lot of articles lately about a clothes
>dryer with a magnetron or klystron inside. Still expensive to buy, but
>cheap to run. I think it will happen when electricity is more expensive.
>
This is an application that makes sense, as there are potential efficiencies
in being able to heat the water in the clothes directly rather than via
heated air. There are other examples, one being the microwaving of diesel
exhaust particulate. Successful pplications of microwave heating are likely
to be ones where the advantage of precise energy targeting outway the losses
in conversion. Water hearing per se just doesn't seem like one of these.

Alan
Alan Muller
Alan Muller & Associates
444 Mansion House Rd.
Bear, DE 19701 USA
(302)834-3466
fax (302)836-3005

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

From bryden at cae.wisc.edu Wed Mar 27 10:40:34 1996
From: bryden at cae.wisc.edu (mark)
Date: Tue Aug 31 21:34:53 2004
Subject: pictures
Message-ID: <199603271543.JAA173988@audumla.students.wisc.edu>

At 11:35 AM 3/25/96 EST, Tom Reed wrote:
[snip]
>MORE PICTURES:
>All of which brings me to the problem of our sending and receiving better
>diagrams of our stoves. It is ridiculous for us to use 1000 words to
describe a
>picture that we can easily draw on our autocad/paintbrush/scanners. My
>Compuserve mailer has a command "send file" and allows me to browse my files,
>pick one and send it. I have done it to other Compuserve friends (my son in
>Long Beach).

[major snip]
>

Tom,

Although I am no expert in e-com stuff I regularly send and receive
drawings, pictures etc. The trick I think is to save them in a GIF format
and attach them to your document. If you are using Netscape the receipt and
viewing seems very easy. I usually don't use Netscape but use Eudora Pro in
this case I have a shareware GIF viewer that I use to view the drawing. If
you need help holler, I usually let my 14 yr. old son figure out how to do
this since I don't like to take the time to search out the ftp/www sites and
read the directions. (He does the same thing for his school, my office
partners, etc.)

Mark Bryden
Dept of Mechanical Engineering
University of Wisconsin
608-238-7421

From larcon at csn.net Wed Mar 27 20:16:12 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:53 2004
Subject: stoves
In-Reply-To: <199603262304.RAA134872@audumla.students.wisc.edu>
Message-ID: <Pine.3.89.9603271738.A3782-0100000@teal.csn.net>

Mark - I decided to send this to the full group, because the
issues are good ones.
Others - I am trying to get caught up and sent a brief message to
Mark, which generated the following.

On Tue, 26 Mar 1996, mark wrote:

> Ron,
>
> I have been going back through my stoves mail and trying to determine
> exactly where everyone is at. I have a couple of questions.
>
> 1. Tom Reed made the comment that you travel to Africa for six months of
> the year. It sounds like an exciting trip! What business or interest takes
> you there? I think you said that you are semi-retired (excuse me if I
> confused you with someone else). What did you retire from?
>
Response . The trip was great - in two 3 month parts. The first
was paid for by a group called IESC (Intl Exec. Service Corps). Mostly
on PV - for a small firm in Zimbabwe. The last part of that was a free
stay in Sudan where I worked on a USAID project in 1982-83.
I went back at my own expense to Zimbabwe for the ISES conference
in September and then worked for teh same firm at local wages for 6 weeks
and then same in Ethiopia - this last mostly on a big multi -kW injera
cooking stove.
I worked at NREL from 1977-1982, then Sudan, then since at solar
things only part time until 1993 when I retired. I am back to full time
renewables topics - of too many types,

> 2. I am confused by this statement. you made in February.
>
> >But with a charcoal maker, the fuelbed isn't "burning" - but
> >rather partly (75%) volatizing. My point was to emphasize that the flame
> >seems to stay constant for tens of minutes and that I'm uncertain as to
> >the exact reason as the pyrolysis front moves over tens of centimeters
> >(also not yet really studied in detail).
>
Now I might say 50% volatizing (of the initial carbon atoms). The
charcoal production is 25% by weight.

> I think my confusion may come in part from my mental picture of the
> "pyrolizing cook stove". I
> think that this is
> a) 2 tin cans with ends removed except for the bottom of the bottom can of
> the same size with a small (1-5 mm) gap between them.

Correct.

> b) The lower can is filled with sticks 2-3 cm in diameter such that the
> primary air from holes punched in the lower can runs lengthwise instead of
> crosswise

Correct.

> c) The stove is lit at the bottom (?)

Definitely not correct. In fact, I can't make it work at all
this way. Lit at the top.

> d) The uncombusted pyrolysis products (some are combusted in the pyrolysis
> zone to provide heat to sustain the pyrolysis reaction ... hence the need
> for primary air) and CO are combusted with the secondary air in the top can

Correct.

> and the blue flame is stabilized on the grill.

The flame is only partly blue - although perhaps the two Toms are
getting better. It is stabilized at the secondary air inlet holes. i
have been mostly trying to get the flame to disappear at the grill/cookpot.

>
> >From this I presume that the pyrolysis zone proceeds from the bottom upward,
> just like the transient operation of a combustor gasifier during startup.
> >From this it seems that the fuel bed is "burning". The phenomenon can be
> described and modeled using standard packed bed modeling equations and
> techniques. The biggest issue being the natural circulation and resulting
> numerical hassles to find the solution due to the sympathetic coupling
> between the air flow rate and the combustion rate in the fuel bed.
>
> Is this basically correct or am I missing something? Please correct any
> misconceptions that I have.

See above corrections. The issue of stability of the thermal
output over many tens of minutes is possibly solved by Etienne's
observation on the change of resistance due to temperature - but I
haven't had time to think that one through.

>
> 3) What are you trying to model?

I am hoping that a good model will show how to optimize the
various dimensions - balancing off efficiency, CO or hydrocarbon
production, etc. There is currently some disagreement about the value of
moisture content.

I thnk this is an expecially interesting geometry to model because
it is azimuthally symmetric and almost time-independent. The fact that
the pyrolysis and combustion zones are well separated should be a help to
modelers.

I think an early interesting simpler model could be two
semi-infinite slabs separated by about 1-2 mm with upward flowing air and
downward-moving pyrolysis zone might be particularly tractable. I
believe that the anisotropy of the diffusivity will be particularly
important.
>
> The papers you asked for should be in the mail tomorrow.
>
> Thanks for your time,
>
> Mark Bryden
>

And yours -
Regards Ron Larson

From tduke at igc.apc.org Thu Mar 28 02:43:06 1996
From: tduke at igc.apc.org (Thomas Duke)
Date: Tue Aug 31 21:34:53 2004
Subject: Fire Truck Fumes Progress
Message-ID: <199603280504.VAA14085@igc3.igc.apc.org>

Hi,

I want to let you know your suggestions for protecting our fire
fighters from diesel fumes are being put to work. So I am sending
this little up-date.

The suggestions you have posted so far are printed and were delivered
to our fire chief this afternoon. So I expect to have a visit with
him in a few days to discuss the issue.

Personally I feel that preheating the trucks with electric heaters is
good. Also that adding some biodiesel to the fuel (I think 20% is
recommended for busses)is also a good Idea. Then I think a smaller
(cheaper) filter will do some good (when used together with preheat
and biodiesel). Starting the engines on a cleaner fuel also sounds
attractive - perhaps starting on 100% biodiesel. Microwave heaters
may also be helpful in cleaning up the exhaust. So I feel we have
some very good leads. Leads that don't cost much.

I don't know which ideas will most appeal to Ken (our fire chief) so
I will let you know what he says. Also I will continue to take any
more suggestions you make to him, because this is a serious problem
with fire trucks in other places also. If he likes your ideas I know
he will share them with other fire departments.

Thanks,

Tom
Tom Duke
4363 Hunt Road
Burlington IA 52601-8917
The Renewable Energy Research Center & Farm (319)754-7384

From tduke at igc.apc.org Thu Mar 28 03:07:35 1996
From: tduke at igc.apc.org (Thomas Duke)
Date: Tue Aug 31 21:34:53 2004
Subject: Model
Message-ID: <199603280504.VAA14141@igc3.igc.apc.org>

Hi,

Wednesday March 27 Ron Larson wrote this:
> I am hoping that a good model will show how to optimize the
>various dimensions - balancing off efficiency, CO or hydrocarbon
>production, etc. There is currently some disagreement about the value of
>moisture content.

I am putting together a model based on this note. So any additonal
information you can give me will help a lot. I am going from general
to specific in my model, so what I need first are the basic cause and
effect relationships. The direction of the relationship will be very
helpful at first. Later I will add the degree of change. This model
can grow and develop as we get more experience. So here is a list of
my beginning relationships.

Chimney height <and> draft
fuel height <and> draft
Fuel-bed diameter <and> power
Efficency <and> CO / hydrocarbons
Primary air inlet size <and> power
Secondary air inlet size <and> flame quality
Fuel air mixing <and> flame quality
Fuel moisture <and> efficency

All I need are the relationships that are involved in producing what
we are concerned about. So if our concerns are efficency, flame
quality, power, CO/hydrocarbons then I need those relationships
related to these things. So let me know if my list is complete.

There are many things that we may consider like temperature of fuel
bed, temperature of gas in mixing chamber, molecular interactions,
quantity of oxygen used, and so on. Some of these may be essential to
the cause and effect relationships connected to the information we
want to know and many of these are interesting to know but not
necessary to create our model. So let me know what additional
relationships we need to consider. Then I will attempt to bring our
model to life.

Ready to make a model,

Tom
Tom Duke
4363 Hunt Road
Burlington IA 52601-8917
The Renewable Energy Research Center & Farm (319)754-7384

From tduke at igc.apc.org Thu Mar 28 05:24:44 1996
From: tduke at igc.apc.org (Thomas Duke)
Date: Tue Aug 31 21:34:53 2004
Subject: Yes, New Stove design?
Message-ID: <199603280504.VAA14106@igc3.igc.apc.org>

Tom Reed wrote:
> Date: 25 Mar 96 11:35:38 EST

> Dear Tom Duke:
>
> Yes, this is a new design to me. I might even try it if you don't mind. .

I tried this design and it has potential. So if you get a chance to
try it I will be very pleased. It was a little harder to light but
did some very interesting things. At times I had some very nice blue
flame. At times it acted like a very large bunsen burner with the air
not properly adjusted. I experienced some very interesting and
unexpected air flow patterns in the fuel bed. So I feel we can learn
something by running a few tests.

I had many holes in the sides of the inside can. Possibly too many
holes. Because of yellow flame after the fire got well established.
Not totally yellow flame. But flame extending above the top of the
stove much like the flame of a very large bunsen burner. However this
part of the flame was mostly yellow. So my first guess is that too
much fuel gas is flowing into the mixing chamber.
>
> It is terribly confusing to try to follow your description and your "morse code"
> picture is garbeled by word wrap.

Sorry the picture didn't come through. I have used this picture
sending technology to a friend in Scotland successfully. So I was
hoping it would open a way for us also to share drawings. I wonder
how your word wrap is functioning? I wonder if it is wrapping in
addition to the normal carriage returns that these e-mail note pads
use? I suspect however that my characters per line is set longer then
yours. Which means that my text also comes out a little garbeled.

I would be willing to try again and work out a system that your
e-mail reader can handle. So let me know how your system functions
ie. how many characters per line and does word wrap retain the
original carriage returns?

> You say . "A lid to cover the
> space between the two cans, so we have a central chimney 3.125 inches
> dia." Does this mean that there is a septum preventing combustion gases exiting
> the outer ring?

Yes, there is a septum. I placed it on after I lit the fire. It was
not a tight fit, so some nice blue flame leaked out around it.

>It is also unclear whether the central "internal chimney" can
> has unlimited accesss to the air under the grate (in which case, maybe none will
> flow to the outer fuel section).

Yes, the internal chimney has unlimited access to the air under the
grate. And it appears that possibly some of the gasses from the fuel
are sucked under the grate then up the chimney. But I had put some
sawdust in the chimney to help get the fire started. So I am not
certain that the gases came from the fuel supply. Because they may
have come from a little sawdust still in the chimney. So this is one
of those interesting airflow patterns that I want to examine more.

>
> MORE PICTURES:
> All of which brings me to the problem of our sending and receiving better
> diagrams of our stoves. It is ridiculous for us to use 1000 words to describe a
> picture that we can easily draw on our autocad/paintbrush/scanners. My
> Compuserve mailer has a command "send file" and allows me to browse my files,
> pick one and send it. I have done it to other Compuserve friends (my son in
> Long Beach).
>
> But Ron Larson says he can't receive it. Can you send receive? Can anyone out
> there?

Yes, I can receive attached files. We have the software to open most
file types. We need the extension on the file name to help us
determine which system to open the file with. Paintbrush is often
pcx. Scanners are often Tiff. JPEG is a favorite of some. And of
course GIFS are popular. But there are many others, so let me know.

I agree that our work requires that we design a system for sharing
drawings. So I will work with you in this task.

> *****
> TOOLS FOR STOVES: I have and use regularly in making my stoves:
> Can opener for removing lids
> Church Key (beer can opener) for making air holes, legs, spacers,...
> Aircraft tin snips for cutting more complex holes
> No-name snips that cut a running strip 1/8 in wide from a sheet
> Long nose, etc. pliers
> Electric drill with wide selection of bits, hole saws etc
> 28 gauge galvanized flashing and 26 gauge sheet, slightly stiffer
> Pop rivets and popper
> Nibbler from Radio Shack that starts from a small hole and takes 1/8 in nibbles
> to make any other size.
>
> I have just found a new (to me) tool. It puts 45 degree, 1/8 in wide crimps
> around the edge of a stove pipe or tin can so that the diameter is reduced a few
> % and you can insert a 4 in D, 5 in high can into another to make a 10 in can.
>
> Are there other tools that some of you have found useful? Is there an electric
> tin snips? (I tend to cut my hands as the metals curl away from the shears).

Watch a furnace man. They have a way of cutting. Also wear gloves.
There is a tool that we used to make our furnace ducts that is some
thing like an end mill. It fits into an electric drill and allows you
to mill out any shape hole. The mill is about 1/4 inch in diameter.
Your local furnace repair people probably have one. They can also
give you some very good tips and show you their tools. So if you get
a chance the furnace people realy know some good procedures.
> *****
> I spoke at length to Ron Larson in church yesterday for the first time in 6
> months and we exchanged penciled sketches of stoves. Very useful.
>
> We discussed commercialization. I explained Bourbaki and we'll check further.
> I suggested that we continue to understand the principles of clean gas stove
> combustion and continue to evolve designs (with pictures I hope). From the
> designs we will begin to understand the principles. We can then design many
> stoves to fit the many occasions of the world's needs. With the net we can
> communicate with others out there who are in a position to make tests and get
> back to us.

I agree, there is a lot of knowledge about gas burning because of the
natural gass industry. So I feel our major contribution is in making
the gas. I think there are lots of excellent gas burner arrangements
all completely engineered that we can draw from. so I think we have
an open door on the burner end (most of the work already done for us
there).
>
> So far, we have accumulated a lot of experience. Ron says I can get digests of
> our discussions with "subscribe stoves-digest" sent to majordomo. He says we
> are up to No. 6 now. One could go through this treasure trove and begin
> selecting out principles.

I would like to see your summary of principles. So if you get a
chance to post it I will enjoy it.
>
> I see the problem in the world stove design of the 1980s that it attracted many
> mechanical engineers trying a potentially infinite number of combinations.
> However, very few principles of design emerged to guide future steps. Second
> problem is that most thought of wood burning stoves, not wood-gas burning as we
> are doing.

It is a matter of motive Tom, as we draw from our experience to help
individuals solve their problems, then we will design succesful
stoves.
>
> Comments? Onward..... TOM REED
>
>
Tom Duke
4363 Hunt Road
Burlington IA 52601-8917
The Renewable Energy Research Center & Farm (319)754-7384

From prasad at tn7.phys.tue.nl Thu Mar 28 05:31:56 1996
From: prasad at tn7.phys.tue.nl (prasad)
Date: Tue Aug 31 21:34:53 2004
Subject: Model
In-Reply-To: <199603280504.VAA14141@igc3.igc.apc.org>
Message-ID: <9603281026.AA17467@tn7.phys.tue.nl>

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From prasad at tn7.phys.tue.nl Thu Mar 28 05:56:11 1996
From: prasad at tn7.phys.tue.nl (prasad)
Date: Tue Aug 31 21:34:53 2004
Subject: Stove modelling vs Fiddling
In-Reply-To: <960326032341_73002.1213_FHM58-2@CompuServe.COM>
Message-ID: <9603281051.AA17570@tn7.phys.tue.nl>

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From bryden at cae.wisc.edu Thu Mar 28 08:29:24 1996
From: bryden at cae.wisc.edu (mark)
Date: Tue Aug 31 21:34:53 2004
Subject: Yes, New Stove design?
Message-ID: <199603281332.HAA61969@audumla.students.wisc.edu>

At 10:21 PM 3/27/96 +0000, Tom Duke wrote:

>
>I agree, there is a lot of knowledge about gas burning because of the
>natural gass industry. So I feel our major contribution is in making
>the gas. I think there are lots of excellent gas burner arrangements
>all completely engineered that we can draw from. so I think we have
>an open door on the burner end (most of the work already done for us
>there).

Tom Duke,

I'm not sure the correlation between this case and natural gas is one to
one. You have different heat contents and flame speeds. If I'm not
mistaken you will need harken back to the days of producer gas. The tools
for designing burners are readily available but I'm not aware of any work in
this area.

Mark Bryden

From prasad at tn7.phys.tue.nl Thu Mar 28 09:16:38 1996
From: prasad at tn7.phys.tue.nl (prasad)
Date: Tue Aug 31 21:34:53 2004
Subject: Model
In-Reply-To: <199603280504.VAA14141@igc3.igc.apc.org>
Message-ID: <9603281411.AA17885@tn7.phys.tue.nl>

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From verhaarp at janus.cqu.edu.au Thu Mar 28 19:10:56 1996
From: verhaarp at janus.cqu.edu.au (Peter Verhaart)
Date: Tue Aug 31 21:34:53 2004
Subject: char stove: ground-based charcoal-making stoves
Message-ID: <9603290013.AA08768@janus.cqu.edu.au>

Hi, Stovers all, elderly and otherwise.

The Poltergeists, Hantu's, Spooks, Jinns and Trolls evidently found someone
who is even more fun. In short, I am back on line at cqu.edu.au. Last night
was the night. I got through and there were 67 messages, some with familiar
content as they had also been sent via msn.com.
Well, I must have found the right incantation, here behind the keyboard, I
feel sure I tried them all, including some new ones inspired by sheer
frustration. The only tangible thing I did was reinstall Mosaic and that
must have kicked the invaders in the right place. I still don't see the
logic of it. I reinstall Mosaic and all of a sudden not only Mosaic connects
but so do the lot, Cyberjack, Eudora, MS Internet Explorer, the lot!

Now some comment on part of some of the messages.

>A few days ago Ron L. wrote:
>> 3. In a conversation on this yesterday, Ron West asked whether there
>> will be sufficient draft to achieve the downward flowing secondary outer
>> air (and prevent smoke exiting through this region between the cones).

Why do you need a shield going up from the bottom of the slit, why not have
the shield extend downward from the top of the slit so between it and the
outer wall of the charring compartment there will be some extra draft
assisting the process. We probably need all the draft we can squeeze out of
our setups.

>> prevent backflow. (Incidentally does anyone know of a good comprehensive
>> reference on the chimney, preferably containing experimental and
>> theoretical results? None of the heat transfer texts I have even mention
>> the chimney.)

A long time ago I came across an article in Brennstoff, Waerme, Kraft,
probably early in the 70's, in my water period. I don't remember the
author's name. I remember coming across power outputs of several MW's, he
was looking into chimneys of thermal power stations. It was in German.

>> b. Getting an optimal spacing (1-2 cm?) for the vertically rising gases
>> can be achieved with a supplementary cylindrical shield matched to each
>> specific pot.

Yes, what would be the ideal gap width for a stove with an inside diameter
of 115 mm. I have used 6, 4.5 and 3 mm but not in a systematic way, not
being a spontaneously systematic person.

Good to be back again.
Cheers

Piet Verhaart

From CKEZAR34 at aol.com Thu Mar 28 21:31:31 1996
From: CKEZAR34 at aol.com (CKEZAR34@aol.com)
Date: Tue Aug 31 21:34:53 2004
Subject: Fire Truck Fumes Progress
Message-ID: <960328213434_364855151@mail06>

Hi
The BioDiesel sounds good if the fuel has no Sulpher
Chuck Kezar

From E.Moerman at stud.tue.nl Fri Mar 29 20:05:15 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:53 2004
Subject: Stoves: simulation data.
Message-ID: <7629.s335192@popserver.tue.nl>

The past few days I had my computer do some number-crunching, so have did
not do much about my email. I hope to get up to date with my email this
weekend. However at the moment I would like to share some of the simulation
results. I think they are interesting.

I checked the influence of the wood density on the charcoal yield for 0%
moisture and a constant irradiation at one surface of 84kW/m2 equivalent to
a blackbody temp of 1103K.
wooddensity kg/m3 char yield (% of weight of dry virgin wood)
900 43%
650 43%
400 43%
The effect only shows in the third significant digit.

Also I checked the influence of the moisture content. Same irradiation level
and for a 650kg/m3 wooddensity.
moisture (% on dry matter basis) charcoal yield %
0 43
10 42
20 41.8
30 41.7
Again hardly any effect.

Finally I checked the influence of the irradiation levels for 20% moisture
and 650 kg/m3.
irradiation (kW/m2) equivalent black body temp (K) char yield (%)
37.5 900 42.7
60 1014 42.2
84 1103 41.8
And again hardly any influence on the char yield.

It must be said that the charcoal yields are not completely realistic and
can be adjusted to obtain more realistic values, but the trend (virtually
constant charcoal yields) is not expected to change.

Another important point to consider is that the pyrolysis in the model
simulation occurs in a 'fuel chamber' with a constant temperature. This is
usually not so for a real stove. Although in the simulation the ultimate
yield of charcoal seems to be the same the time it takes to get to this
point can differ substantially (easily a factor of 5). A real stove cools
down during this period and in practice it can be expected that the charcoal
is harvested far before the ultimate yield due to pyrolysis is reached.

I hope to come with more results next week, although I have to do some more
writing first.

Go on crunching.

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

From 73002.1213 at compuserve.com Sat Mar 30 08:06:25 1996
From: 73002.1213 at compuserve.com (Thomas Reed)
Date: Tue Aug 31 21:34:53 2004
Subject: Simple Modelling with experiments
Message-ID: <960330130733_73002.1213_FHM45-1@CompuServe.COM>

Prasad, Tom Duke, Etienne and other potential modellers:

I applaud the interest in modelling here and Prasad's most recent comments.

I think you underestimate the value (a) of experiment and (b) of sitting and
thinking. The problem with thinking by itself if that you can't a priori order
the relative importance of the competing effects. However, with simple
experiments you can often eliminate the less important ones. Reflect on the
very few experiments available to Einstein on which he based all of his Physics
and Physical Chemistry results.

I hope that we will move toward a simple (Boyles and Charles law type) model
that stove builders can comprehend and modify to suit local needs. We don't
need a differential equation fluid flow second virial type model requiring a PhD
to comprehend and inapplicable when one input is changed.

Obviously some of you have been institutionalized too long. 80,000-150,000
Guilders indeed! If the purpose is to support an army of graduate students and
a 150% overhead for the University, this is probably a good figure. If the
purpose is to supply a low cost, close coupled gasifier stove for 2 billion
people, it is a red herring.

As a not-too-retired, not-too-rich scientist. I am quite happy in my present
laboratory (garage #3) with instrumentation I have accumulated over a decade
costing less than $2000. Here's my list: Absolutely, a good balance; better
yet, one accurate to a few mg in a few kg and another accurate to a few g in 100
kg; hopefully, thermocouples; possibly a data logger, but I find that by the
time I have gotten it running and calibrated, I could have run the experiment
ten times, logging with a pencil in my notebook. Just as the data logger is
ready, I change the experiment so need different sensors. I do occasionally
long for a gas chromatograph and good gas analyses. Acquiring that could put
off the good stove another few years. NREL is setting up a "user facility" and
I hope to be able to cadge the necessary skills and equipment. I listed useful
tools the other day. And I need lots of pots and containers.

I am thinking of the "principles" list that I would propose, but not ready yet.
I will be travelling with my wife to Illinois and Indiana next week, but expect
to keep in touch on the Net.

Onward and Upward Tom Reed

From larcon at csn.net Sat Mar 30 10:34:14 1996
From: larcon at csn.net (Ronal Larson)
Date: Tue Aug 31 21:34:53 2004
Subject: Stoves: simulation data.
In-Reply-To: <7629.s335192@popserver.tue.nl>
Message-ID: <Pine.3.89.9603300836.A3659-0100000@teal.csn.net>

Etienne: This isvery interesting data. Could you describe a little
more about the model? More comments below on a truncated version of your
material.

On Sat, 30 Mar 1996, E.Moerman wrote:

> wooddensity kg/m3 char yield (% of weight of dry virgin wood)
> 900 43%
> 650 43%
> 400 43%
> The effect only shows in the third significant digit.

I have reported 25% consistently - but this was on the basis of
moist fuel - so the yield was higher - and independent of type.

>
> Also I checked the influence of the moisture content. Same irradiation level
> and for a 650kg/m3 wooddensity.
> moisture (% on dry matter basis) charcoal yield %
> 0 43
> 10 42
> 20 41.8
> 30 41.7
> Again hardly any effect.
>
Can you add anything about other aspects of the combustion that
might be affected by moisture?

> Finally I checked the influence of the irradiation levels for 20% moisture
> and 650 kg/m3.
> irradiation (kW/m2) equivalent black body temp (K) char yield (%)
> 37.5 900 42.7
> 60 1014 42.2
> 84 1103 41.8
> And again hardly any influence on the char yield.
>
> It must be said that the charcoal yields are not completely realistic and
> can be adjusted to obtain more realistic values, but the trend (virtually
> constant charcoal yields) is not expected to change.
>
What adjustments are you thinking of?

> Another important point to consider is that the pyrolysis in the model
> simulation occurs in a 'fuel chamber' with a constant temperature. This is
> usually not so for a real stove.

But it is true in a pyrolyzing stove (after the pyrolysis front
reaches the point in question). See Tom Reed's report last week.

> Although in the simulation the ultimate
> yield of charcoal seems to be the same the time it takes to get to this
> point can differ substantially (easily a factor of 5). A real stove cools
> down during this period and in practice it can be expected that the charcoal
> is harvested far before the ultimate yield due to pyrolysis is reached.

Are you talking here only of the ordinary stoves? The
charcoal-making stove harvests nothing until all wood has turned to
charcoal - with essentially no cooling.
>
> I hope to come with more results next week, although I have to do some more
> writing first.
>
> Go on crunching.
>
> Etienne

Thanks for this contribution. Ron

From E.Moerman at stud.tue.nl Sat Mar 30 17:57:12 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:53 2004
Subject: Simple Modelling with experiments
Message-ID: <86345.s335192@popserver.tue.nl>

Tom Reed:

I don't think I do underestimate the value of experiments, but I limit my
experiments to about 10 a year. The remainder of the year I am trying to
squeeze out all the info I can. Using advanced models give enormous
additional directly usuable info. I also do a few simple experiments to
check a few ideas developed.

Tom Reed, original text:
> I hope that we will move toward a simple (Boyles and Charles law type) model
> that stove builders can comprehend and modify to suit local needs. We don't
> need a differential equation fluid flow second virial type model requiring
> a PhD to comprehend and inapplicable when one input is changed.

Etienne, comment:
I don't think something as simple as Boyles law is possible, however I am
looking for ways to condense the differential equations for fluid flow into
much simpler equations.

Tom Reed, original text:
> Obviously some of you have been institutionalized too long. 80,000-150,000
> Guilders indeed! If the purpose is to support an army of graduate students

Etienne, comment:
I am afraid Prasad overestimated the cost of equipment:
For 15,000-20,000 US$ you can have a well equiped lab including gas
analysis. Of course the most important cost is the cost for good personnel.
Creative personel can do quite advanced experiment even with simple
equipment.

Etienne
---------------------------------------------
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 Sat Mar 30 17:57:07 1996
From: E.Moerman at stud.tue.nl (E.Moerman)
Date: Tue Aug 31 21:34:53 2004
Subject: Stoves: simulation data II.
Message-ID: <86340.s335192@popserver.tue.nl>

Ron:

I am glad that you found the results interesting even though they are still
limited. I will answer your questions below copying relevant text.

> Etienne: This isvery interesting data. Could you describe a little
> more about the model? More comments below on a truncated version of your

The model exist of a pyrolysis process consisting of the following primary
reactions:
WOOD -> GAS
WOOD -> TAR
WOOD -> CHAR
where GAS stands for volatile components that are in gas phase at room
temperature while TAR stands for gas components that are a liquid at room
temperature, but are a gas at the pyrolysis temperatures.
Further I consider the secondary reaction:
TAR -> GAS
All reactions have their own reaction rate, described by an Arrhenius
equation.

In addition to the pyrolysis process I take into account evaporation and
condensation of the moisture in the wood.

Continuity equations are the usual ones, using the Arrhenius type reaction
rates wherever appropriate.
The momentum equation is the Darcy equation.
Energy equation is also the usual energy equation.

It would take far too much text and time to write down all the details I
consider, but if you have specific questions let me know and I will try to
answer them. A detailed description is hopefully available in about 2
months.

Ron Larson wrote:
> I have reported 25% consistently - but this was on the basis of
> moist fuel - so the yield was higher - and independent of type.

Etienne replies:
My yields depend on the frequency factors and activation energies that I
choose. I will try to get estimates for these from experimental values.

Ron Larson asked:
> Can you add anything about other aspects of the combustion that
> might be affected by moisture?

Etienne replies:
I can give you about any info you want. However it will take quite a lot of
calculation time. More details will follow as I write things down in a more
formal way. If you want any specific info let me know and I will make sure
that I save the relevant info during the simulations.

Etienne, original text:
>> It must be said that the charcoal yields are not completely realistic
>> and can be adjusted to obtain more realistic values, but the trend
>> (virtually constant charcoal yields) is not expected to change.
>>
Ron Larson's question:
> What adjustments are you thinking of?

Etienne, reply:
The frequency factors and activation energies I mentioned earlier.

Etienne, original text:
>> Although in the simulation the ultimate
>> yield of charcoal seems to be the same the time it takes to get to this
>> point can differ substantially (easily a factor of 5). A real stove
>> cools down during this period and in practice it can be expected that
>> the charcoal is harvested far before the ultimate yield due to pyrolysis
>> is reached.

Ron's comment:
> Are you talking here only of the ordinary stoves? The
> charcoal-making stove harvests nothing until all wood has turned to
> charcoal - with essentially no cooling.

Etienne, reply:
What is important here is the temperature of the main pyrolysis area and its
immediate environment. In the charcoal making stove this is probably ok.
However lab analysis shows 20% pure char content. A 25% yield would mean
that the result is a comnination of 5% wood and 20% char. This is the result
of too slow reactions. Increasing the reaction rates by increasing
temperature would also increase the combustion of charcoal (not yet included
in this simulation) thus reducing the charcoal yield. For better judgement
of these points a more detailed look is required and it will take several
weeks before I can provide that.

BioEnergy Lists: Improved Biomass Cooking Stoves

March 1996 Biomass Cooking Stoves Archive