BioEnergy Lists: Improved Biomass Cooking Stoves

From tmiles at TRMILES.COM Sat Aug 2 14:33:48 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:34 2004
Subject: Headline - Another charcoal-stove group commits suicide
Message-ID: <SAT.2.AUG.2003.113348.0700.TMILES@TRMILES.COM>

A reminder of the hazards of carbon monoxide:

Another charcoal-stove group commits suicide

URL: http://www.smh.com.au/articles/2003/05/25/1053801280870.html

May 26 2003

One man and two women were found dead in an apartment in Kyoto over the
weekend, in yet another charcoal-stove suicide pact organised in Japan
through internet connections. The three apparently died from carbon monoxide
poisoning several days earlier.

A clay stove with burnt pieces of charcoal was found in a sealed room in the
apartment owned by the 30-year-old man, police said.

Police said they searched the room late on Saturday and found a suicide note
which read: "I am dying because I feel pessmistic about this world."

The women were from different Japanese cities. They came to the apartment
after they contacted each other through an internet site encouraging group
suicide.

The man was found to have logged on to the site, police said.

Japan has been shocked by a string of suspected internet suicide pacts
involving Japanese youths, which since February 11 have claimed the lives of
15 people.
Last Wednesday, three men in their 20s were found dead in a car parked on a
country road in Ueno village, about 120 kilometres north-west of Tokyo.

The car was sealed and filled with carbon monoxide from a charcoal stove.

AFP

From elk at WANANCHI.COM Wed Aug 6 19:37:25 2003
From: elk at WANANCHI.COM (Elsen Karstad)
Date: Tue Aug 10 18:30:34 2004
Subject: Ashden Award 2004
Message-ID: <WED.6.AUG.2003.163725.0700.ELK@WANANCHI.COM>

Stovers;

This just in:

The Ashden Trust is inviting submissions for the Ashden Awards for
Sustainable Energy 2004. We hope to offer five first prizes of up to
?30,000 each will be awarded to outstanding sustainable energy projects
(three for developing
countries and two for the UK). The awards are for community-based renewable
energy and full details of criteria and application instructions can be
found on thewebsite: www.ashdenawards.org. Overseas applicants will be
asked to send a two-page concept note by 14th November 2003 (forms will be
available on the website from mid-September). The closing date for UK
applicants is 15th January.

We hope to publicise the awards as widely as possible.

We look forward to receiving submissions in due course, and by the 14th
November 2003 deadline (overseas applicants), but potential applicants
should read the website carefully to find out how to apply.

Yours sincerely

 

Jane Shepherd
The Ashden Trust

 

The Ashden Awards for Sustainable Energy
The Sainsbury Family Charitable Trusts
Allington House (1st Floor)
150 Victoria Street
London SW1E 5AE

Direct Line: 020 7410 7044
Swtichboard: 020 7410 0330
Fax: 020 7410 0332

--------------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi, Kenya

From solar1 at ZUPER.NET Mon Aug 11 21:58:56 2003
From: solar1 at ZUPER.NET (Sobre la Roca: Energ=?ISO-8859-1?B?7Q==?=a Solar para el
Desarrollo)
Date: Tue Aug 10 18:30:34 2004
Subject: Peru 2 - Counterflow heat exchange in cooking
In-Reply-To: <00df01c38ea0$6cea1ea0$576c0443@net>
Message-ID: <MON.11.AUG.2003.215856.0400.SOLAR1@ZUPER.NET>

On 10/9/03 15:16, "Ron Larson" <ronallarson@QWEST.NET> wrote:

> Stovers: In #1 I said:
>
>
> Ps - wood (split and maybe 1/2 meter long) was available in at least one
> location for 5 "Soles" ($1.50) per quintal - which I think is 100 kg. Can
> anyone confirm the last value?
>
Ron, here in Bolivia 4 arobas (25 pounds) = 1 quintal (100 pounds)
--
"Most people aim at nothing in life. . .and hit it with amazing accuracy."

David Whitfield
Director
Sobre la Roca
P.O. Box 4723
La Paz Bolivia South America
591-2-2414882 office 591 715 16356 cellular

solar1@zuper.net
aguaviva@zuper.net
dewv@yahoo.com

http://www.solarcooking.org/media/broadcast/whitfield/bio-whitfield.htm

http://www.thehungersite.com

From robertoescardo at ARNET.COM.AR Tue Aug 12 16:56:07 2003
From: robertoescardo at ARNET.COM.AR (=?iso-8859-1?Q?Roberto_Escard=F3?=)
Date: Tue Aug 10 18:30:34 2004
Subject: Peru 2 - Counterflow heat exchange in cooking
Message-ID: <TUE.12.AUG.2003.175607.0300.ROBERTOESCARDO@ARNET.COM.AR>

How much does a quintal weigths?
In Argentina, used mostly for grains, is 100 kg, but.in Per? is probably
the spanish "metrified" , I guess 50 kg and not 46.
Many ancient units are "metrified" in latin America, ex: a "legua" is just 5
kilometers and not 4.2 as the "original" spanish.
A very nice place about units: http://www.unc.edu/~rowlett/units/
Regards
Roberto.

----- Original Message -----
From: "Sobre la Roca: Energ?a Solar para el Desarrollo" <solar1@ZUPER.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Monday, August 11, 2003 10:58 PM
Subject: Re: [STOVES] Peru 2 - Counterflow heat exchange in cooking

> On 10/9/03 15:16, "Ron Larson" <ronallarson@QWEST.NET> wrote:
>
> > Stovers: In #1 I said:
> >
> >
> > Ps - wood (split and maybe 1/2 meter long) was available in at least one
> > location for 5 "Soles" ($1.50) per quintal - which I think is 100 kg.
Can
> > anyone confirm the last value?
> >
> Ron, here in Bolivia 4 arobas (25 pounds) = 1 quintal (100 pounds)
> --
> "Most people aim at nothing in life. . .and hit it with amazing accuracy."
>
> David Whitfield
> Director
> Sobre la Roca
> P.O. Box 4723
> La Paz Bolivia South America
> 591-2-2414882 office 591 715 16356 cellular
>
> solar1@zuper.net
> aguaviva@zuper.net
> dewv@yahoo.com
>
> http://www.solarcooking.org/media/broadcast/whitfield/bio-whitfield.htm
>
>
> http://www.thehungersite.com

From rdboyt at YAHOO.COM Tue Aug 12 23:32:57 2003
From: rdboyt at YAHOO.COM (Richard Boyt)
Date: Tue Aug 10 18:30:34 2004
Subject: Finding Clay Update
Message-ID: <TUE.12.AUG.2003.203257.0700.RDBOYT@YAHOO.COM>

Subject: Ceramics for Stoves: Finding Clay, Part 1, Update.

Several months of gathering and testing nearby deposits of native earthenware clay started with breaking up damp clumps dug from the sides of an excavated pond, and tumbling them into a strainable slurry with rocks tumbling in a cement mixer. A much better and faster way, I have found, is to wade out into the pond and scoop up buckets of the sometimes knee-deep mud. The closer you are to the edge where the water drains into the pond, carrying its load of sediment, the coarser the particles of sediment clay, mixed with appreciable amounts of sand. The furthest, out toward the middle of the pond, I find the finer particles of clay mixed with diminished amounts of finer sand. This is explained by the fact that rapidly running water can carry with it fairly large and heavy particles. But when the stream slows as it enters the pond, the larger particles settle out rather quickly, allowing the finer lighter particles to move further out into the pond, where they finally settle in the now
still water. This uses nature's sediment settling process to save the considerable time required to break solid chunks of dry clay for straining and refining.

I refine this clay by adding enough water to make a thin soup, allowing it to pass through three successively finer screens to remove unwanted organic material and the few pebbles that found their way into the mix.

 

---------------------------------
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software

From robertoescardo at ARNET.COM.AR Tue Aug 12 23:42:38 2003
From: robertoescardo at ARNET.COM.AR (=?iso-8859-1?Q?Roberto_Escard=F3?=)
Date: Tue Aug 10 18:30:34 2004
Subject: About units
Message-ID: <WED.13.AUG.2003.004238.0300.ROBERTOESCARDO@ARNET.COM.AR>

Thanks Derick. I copy your answer to the list because it is very
instructive. Possible my guess is wrong and in Peru also the quintal is 46
kg.
In our Argentina, and Chili as long as I know, we keep the ancient spanish
or english names as abbreviations for exact metric quantities, so if you go
to the carpenter and ask for a 1 (feet) by 1 (inch) 3 meters (yes, lenght is
measured in meters) board you will actually get a 30 by 2,5 (exactly)
centimeters 3 meters long one!! Some very funny histories about it, most of
them surely not true.
BTW: In our country wood is often sold by volume, but "un metro" (one meter)
is actually a 1 x 1 x 0.3 meters stack, 1/3 cubic meter!! Other measures are
"one bolsa", a standart potatoes sack: something like 90 x 50 centimeters
empty or a "chata": the load of a pick-up. In urban areas it is usually sold
by weight, always in kilos or (metric) tons.
Regards
Roberto.

----- Original Message -----
From: "Derick Calderon" <entre16@intelnet.net.gt>
To: "Roberto Escard?" <robertoescardo@ARNET.COM.AR>
Sent: Tuesday, August 12, 2003 10:27 PM
Subject: Re: [STOVES] Peru 2 - Counterflow heat exchange in cooking

> Here in Guatemala we use one pound equals 460 grams and a quintal weighs
> 100 pounds therefor as you mention a quintal is also equivalent to 100
> pounds or 46 Kilograms.
>
> Cordialy
> Derick Calderon
> Tel 502 3671197 Fax 502 3671196
> 7 Ave 15-79 Guatemala 001010
> ----- Original Message -----
> From: "Roberto Escard?" <robertoescardo@ARNET.COM.AR>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Tuesday, August 12, 2003 3:56 PM
> Subject: Re: [STOVES] Peru 2 - Counterflow heat exchange in cooking
>
>
> > How much does a quintal weigths?
> > In Argentina, used mostly for grains, is 100 kg, but.in Per? is probably
> > the spanish "metrified" , I guess 50 kg and not 46.
> > Many ancient units are "metrified" in latin America, ex: a "legua" is
just
> 5
> > kilometers and not 4.2 as the "original" spanish.
> > A very nice place about units: http://www.unc.edu/~rowlett/units/
> > Regards
> > Roberto.
> >
> >
> > ----- Original Message -----
> > From: "Sobre la Roca: Energ?a Solar para el Desarrollo"
<solar1@ZUPER.NET>
> > To: <STOVES@LISTSERV.REPP.ORG>
> > Sent: Monday, August 11, 2003 10:58 PM
> > Subject: Re: [STOVES] Peru 2 - Counterflow heat exchange in cooking
> >
> >
> > > On 10/9/03 15:16, "Ron Larson" <ronallarson@QWEST.NET> wrote:
> > >
> > > > Stovers: In #1 I said:
> > > >
> > > >
> > > > Ps - wood (split and maybe 1/2 meter long) was available in at least
> one
> > > > location for 5 "Soles" ($1.50) per quintal - which I think is 100
kg.
> > Can
> > > > anyone confirm the last value?
> > > >
> > > Ron, here in Bolivia 4 arobas (25 pounds) = 1 quintal (100 pounds)
> > > --
> > > "Most people aim at nothing in life. . .and hit it with amazing
> accuracy."
> > >
> > > David Whitfield
> > > Director
> > > Sobre la Roca
> > > P.O. Box 4723
> > > La Paz Bolivia South America
> > > 591-2-2414882 office 591 715 16356 cellular
> > >
> > > solar1@zuper.net
> > > aguaviva@zuper.net
> > > dewv@yahoo.com
> > >
> > >
http://www.solarcooking.org/media/broadcast/whitfield/bio-whitfield.htm
> > >
> > >
> > > http://www.thehungersite.com
> >
>
>

From crispin at NEWDAWN.SZ Wed Aug 13 10:14:38 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:34 2004
Subject: Gasifying Newspaper
Message-ID: <WED.13.AUG.2003.161438.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers and Newspaper Readers

Last Friday night David Hancock (the famous) and I tried cooking on a Vesto
with newspapers only, meaning they were simply folded and rolled up into a
hollow tube and lit - no wood, no starters. The idea was to avoid having to
make a briquette.

This was surprisingly successful. The problems revolved around keeping it
lit as when bottom lit it tended to smoke a great deal which was OK but the
wind would enhance the production of smoke (which was burning very nicely on
top) and chooke the fire by using all the oxygen.

More successful was top lighting as it worked like a gasifier.

It was important to try toget it burning on the outside because the air
jetting in through the side of the combustion chamber would work little
blowtorches and did a good job of charcoaling then burning the papers.
After a time it turns into a stiff black charcoaling lump looking rather
like a ragged full toilet roll.

Another problem was that the un-attached papers would burn beautifully
inside the hole and then peel over and block the air.

All thing considered, having tried different tube heights, the roll should
be about 150mm high and not have a centre hole. It should clear the side
walls by a few mm and be top lit. It works as a true gasifier in this
condition as there isn't enough air to burn well at the bottom. It makes
masses of smoke which is burned immediately above the newspaper in a clean
if rather 'leaflet' filled flame. It is a little messy but it did give off
a useful heat for an hour. That took one "Mail and Guardian" which is a
modest sized weekly broadsheet.

I think it would benefit from some sort of screen (mantle) on which the
combustion takes place. I have calculated the total draft at 4 Pascals so
it dances well.

Regards
Crispin

PS I have pics if anyone wants.

From tombreed at COMCAST.NET Thu Aug 14 08:38:15 2003
From: tombreed at COMCAST.NET (tombreed)
Date: Tue Aug 10 18:30:34 2004
Subject: Gasifying Newspaper
Message-ID: <THU.14.AUG.2003.063815.0600.TOMBREED@COMCAST.NET>

Dear Crispin:

Congratulations on your toplit newspaper gasifier stove. I presume it was
natural draft.

The problem with natural draft toplit gasifiers is that they require a short
or longer section above the combustion air holes to provide natural draft.
(Even the flame of a match produces its own draft - but not much.)

A < 1 watt blower into the secondary air holes will provide the equivalent
draft of a 10 foot chimney.

~~~~~~
Newspapers are usually hard to burn, but at least they are typically dry.
We have operated our WoodGas Stoves with up to 30% moisture, but more than
that will probably be better bottom lit.

I hope others will take this up. Lots of junk mail in the world.....

~~~~~~~~~~

Yes please, I'd like some pictures...

Onward

TOM REED

 

Yours truly,

Dr. Thomas Reed
tombreed@comcast.com
www.woodgas.com
----- Original Message -----
From: "Crispin" <crispin@newdawn.sz>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Wednesday, August 13, 2003 8:14 AM
Subject: [STOVES] Gasifying Newspaper

> Dear Stovers and Newspaper Readers
>
> Last Friday night David Hancock (the famous) and I tried cooking on a
Vesto
> with newspapers only, meaning they were simply folded and rolled up into a
> hollow tube and lit - no wood, no starters. The idea was to avoid having
to
> make a briquette.
>
> This was surprisingly successful. The problems revolved around keeping it
> lit as when bottom lit it tended to smoke a great deal which was OK but
the
> wind would enhance the production of smoke (which was burning very nicely
on
> top) and chooke the fire by using all the oxygen.
>
> More successful was top lighting as it worked like a gasifier.
>
> It was important to try toget it burning on the outside because the air
> jetting in through the side of the combustion chamber would work little
> blowtorches and did a good job of charcoaling then burning the papers.
> After a time it turns into a stiff black charcoaling lump looking rather
> like a ragged full toilet roll.
>
> Another problem was that the un-attached papers would burn beautifully
> inside the hole and then peel over and block the air.
>
> All thing considered, having tried different tube heights, the roll should
> be about 150mm high and not have a centre hole. It should clear the side
> walls by a few mm and be top lit. It works as a true gasifier in this
> condition as there isn't enough air to burn well at the bottom. It makes
> masses of smoke which is burned immediately above the newspaper in a clean
> if rather 'leaflet' filled flame. It is a little messy but it did give
off
> a useful heat for an hour. That took one "Mail and Guardian" which is a
> modest sized weekly broadsheet.
>
> I think it would benefit from some sort of screen (mantle) on which the
> combustion takes place. I have calculated the total draft at 4 Pascals so
> it dances well.
>
> Regards
> Crispin
>
> PS I have pics if anyone wants.
>

From rmiranda at INET.COM.BR Thu Aug 14 08:53:43 2003
From: rmiranda at INET.COM.BR (Rogerio Carneiro de Miranda)
Date: Tue Aug 10 18:30:34 2004
Subject: Peru 2 -
In-Reply-To: <007701c391b8$f9610180$bc6c0443@net>
Message-ID: <THU.14.AUG.2003.095343.0300.RMIRANDA@INET.COM.BR>

Ron:

In Central America, 1 quintal means 100 pounds, about 45 kg.

Regarding soap stone, here in Minas Gerais state, Brazil, soap stone pots
for cooking is quite common, you can buy them in the roadsides near Ouro
Preto. Also they are selling plates of about 2 cm thick X 30 to 45 cm in
diameter, with copper holders, that people are using for baking pizza for
instance. You have to use only wooden spoons for these pots.

Soap stone pots are very common in brazilian cuisine self-serve
restaurants operated by woodstoves. Usually it is a large masonry
woodstove with a cast iron griddle, clay chimney, oven and water heater
where food is keep there warm, inside soap stone pots, and clients come to
the stove to serve it self and pays for the food based on weight. They are
kind of traditional looking restaurants that has became very popular in the
past 20 years. Lots of restaurants now advertise that they are operated by
woodstove, which is a good marketing strategy here.

In Peru also near Cuzco I saw many houses without chimney, but with a
window opening in the roof just above the stove, like an eave, you can
open and close it as need with a stick. Did you see those?

rogerio

At 10:53 a.m. 13/10/03 -0600, Ron Larson wrote:
>Sobre:
>
> Thanks for the update. Sorry that you too haven't gotten yet completely
>to all-metric. 100 kg sounded like too heavy a load for a convenient
>measure. What is your price in different parts of Bolivia?
>
> I should have listed the Peruvian quintal price not at US$1.50 - but
>rather at $1.45. This makes the price in parts of Peru about 3.2 US cents
>per kilo.
>
>Ron
>
>----- Original Message -----
>From: Sobre la Roca: Energ?a Solar para el Desarrollo <solar1@zuper.net>
>To: Ron Larson <ronallarson@qwest.net>; <STOVES@listserv.repp.org>
>Sent: Monday, August 11, 2003 7:58 PM
>Subject: Re: [STOVES] Peru 2 - Counterflow heat exchange in cooking
>
>
> > On 10/9/03 15:16, "Ron Larson" <ronallarson@QWEST.NET> wrote:
> >
> > > Stovers: In #1 I said:
> > >
> > >
> > > Ps - wood (split and maybe 1/2 meter long) was available in at least one
> > > location for 5 "Soles" ($1.50) per quintal - which I think is 100 kg.
>Can
> > > anyone confirm the last value?
> > >
> > Ron, here in Bolivia 4 arobas (25 pounds) = 1 quintal (100 pounds)
> > --
> > "Most people aim at nothing in life. . .and hit it with amazing accuracy."
> >
> > David Whitfield
> > Director
> > Sobre la Roca
> > P.O. Box 4723
> > La Paz Bolivia South America
> > 591-2-2414882 office 591 715 16356 cellular
> >
> > solar1@zuper.net
> > aguaviva@zuper.net
> > dewv@yahoo.com
> >
> > http://www.solarcooking.org/media/broadcast/whitfield/bio-whitfield.htm
> >
> >
> > http://www.thehungersite.com
> >
> >
> >

From tmiles at TRMILES.COM Fri Aug 15 18:37:14 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:34 2004
Subject: [ethos] charcoal recipe
Message-ID: <FRI.15.AUG.2003.153714.0700.TMILES@TRMILES.COM>

Boiler Point is published by Intermediate Technology Development Group
(ITDG). Editor Liz Bates Boiling.Point@itdg.org.uk does a great job.

http://www.itdg.org/home.html?html/energy/boilingpoint.htm~mainFrame

Dean must be referring to an upcoming issue which should be No. 49

Tom Miles

----- Original Message -----
From: "AES" <aes@bitstream.net>
To: "Dean Still" <dstill@epud.net>; "ethos" <ethos@vrac.iastate.edu>;
"Elizabeth Bates" <elizabethb@itdg.org.uk>
Sent: Friday, August 15, 2003 2:44 PM
Subject: Re: [ethos] charcoal recipe

> Where is the Boiling Point journal available??
>
> Thanks, Bruce
>
>
> ----- Original Message -----
> From: "Dean Still" <dstill@epud.net>
> To: "ethos" <ethos@vrac.iastate.edu>; "Elizabeth Bates"
> <elizabethb@itdg.org.uk>
> Sent: Thursday, August 14, 2003 2:42 PM
> Subject: [ethos] charcoal recipe
>
>
> > Dear ETHOS:
> >
> > Answering how to make a 6 brick Rocket stove charcoal/clay combustion
> > chamber...Is this clear? Look for all the recipes and more in Boiling
> Point
> > 47 coming soon to a stover near you. If you don't get Boiling Point, the
> > world's best vernacular cooking journal, I think that it's free to those
> > interested!
> >
> > Best,
> >
> > Dean
> >
> > CHARCOAL/CLAY BRICK RECIPE
> >
> > Filler : Charcoal dust (fine) 500 grams
> >
> > Clay (damp, 18% water) : 900 grams
> >
> > Water: 800 grams
> >
> > Fired at : 1050 C
> >
> > Density : 0.671 gr/cc
> >
> > Damon's advice is to follow this recipe first, then change as needed.
The
> > material is runny in the mold, you need to leave material in mold for
> > several days to a week until dry. Will shrink appreciably when
fired...You
> > will need more than this to fill our standard mold...
> >
> > Here are the dimensions for the Rocket six brick combustion chamber
molds.
> > TAKE A DEEP BREATH... You will need 6 molds per stove...
> >
> > Draw a horizontal line on a piece of paper that is 2 and 5/8 inch long.
> Use
> > a protractor and draw two lines at 60 degrees from the two ends of the
> > horizontal line. These lines at 60 degrees create a bucket not a
triangle,
> > OK? The two lines at 60 degrees are 3 inches long...
> >
> > Connect the ends of these two 3 inch long lines creating a line
parrallel
> to
> > the first line drawn. This newest line is 5 and 5/8 inches long...You
> should
> > now have a trapazoid on your paper. The two parrallel lines are 2 and
3/4
> > inch apart.
> >
> > Because there are 360 degrees in a circle and we are making six bricks
to
> > create a hollow cylinder the most important sides are those at 60
degrees.
> > Everything else is less important...Larry's advice is to make 6
trapazoids
> > out of plywood and join them together making sure that they form a
> cylinder
> > of the proper dimensions. Then make 12 equally sized trapazoidal pieces
> from
> > wood or plywood. Make the sides of the mold from plywood. The two sides
> are
> > 12 inches long by 3 inches wide...The sides are glued , screwed or
nailed
> to
> > the trapazoidal end pieces creating a mold to be filled with ceramic
> > material.
> >
> >
> > BEST OF LUCK!!!!
> >
> > Dean
> >
> >
> >
> >
>
>

From dstill at EPUD.NET Sat Aug 16 18:15:44 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:34 2004
Subject: Testing Stoves
Message-ID: <SAT.16.AUG.2003.151544.0700.DSTILL@EPUD.NET>

Dear Friends,

I've been working with Rob Bailis, Damon Ogle and Dr. Alan Berick comparing
water boiling tests for wood burning cooking stoves for the last several
months. The PHU water boiling test that we used at the ETHOS Stove Testing
and Design Seminar in June was obviously wrong: stoves that would do well at
cooking did not score as well as stoves that just made a lot of steam. I had
not realized before that experience of looking at many stoves at the same
time that the Percent Heat Utilized test often rewards production of excess
steam. Tami Bond had made this point in discussion with Emma George but I
was too dim to catch her meaning.

Cooking food is accomplished most effectively if the stove can deliver both
high power and then turn down successfully. In simmering we want to replace
energy lost keeping the water at a constant temperature below full rolling
boil. A stove that uses the least amount of wood to accomplish simmering
will usually be most fuel efficient because simmering food like beans goes
on for long periods of time. High power is usually used for shorter periods
of time...

These realizations on my part are due to ignorance: Prasad '84, Baldwin '87,
Visser '03, VITA'85 had gone through this reasoning and proposed alternate
testing methods, like specific consumption, that do predict cooking
performance. Using the new tests, which establish fuel use at high and low
power, focused my attention on how low a good stove needs to turn down.
When lids are used on pots it takes very little wood burning per minute to
maintain water temperatures just below full boil, around THREE TO FOUR GRAMS
PER MINUTE or so depending on stove and pot in my experiments! High power in
the Jiko, Three Stone and Rocket uses between 23 to 28 grams of wood per
minute. (I am using 5 litres of water in my experiments.) The insulated
stove, by the way, boils the water in about half the time.

As I've said, all of this has been written before, most recently I suppose
by Visser '03. But reflecting on how little wood is needed for simmering has
been instructive for me...

All Best,

Dean

From kchisholm at CA.INTER.NET Sun Aug 17 21:43:52 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:34 2004
Subject: Testing Stoves
Message-ID: <SUN.17.AUG.2003.224352.0300.KCHISHOLM@CA.INTER.NET>

Dear Dean

A few months ago, Lanny Hanson addressed the issue of meaningful tests for
stoves, and derived a test based on the grams of wood required to cook a
meal.

Wouldn't this be a real and very practical and very meaningful test protocol
to follow?

Kindest regards,

Kevin Chisholm

----- Original Message -----
From: "Dean Still" <dstill@epud.net>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, August 16, 2003 7:15 PM
Subject: [STOVES] Testing Stoves

> Dear Friends,
>
> I've been working with Rob Bailis, Damon Ogle and Dr. Alan Berick
comparing
> water boiling tests for wood burning cooking stoves for the last several
> months. The PHU water boiling test that we used at the ETHOS Stove Testing
> and Design Seminar in June was obviously wrong: stoves that would do well
at
> cooking did not score as well as stoves that just made a lot of steam. I
had
> not realized before that experience of looking at many stoves at the same
> time that the Percent Heat Utilized test often rewards production of
excess
> steam. Tami Bond had made this point in discussion with Emma George but I
> was too dim to catch her meaning.
>
> Cooking food is accomplished most effectively if the stove can deliver
both
> high power and then turn down successfully. In simmering we want to
replace
> energy lost keeping the water at a constant temperature below full rolling
> boil. A stove that uses the least amount of wood to accomplish simmering
> will usually be most fuel efficient because simmering food like beans goes
> on for long periods of time. High power is usually used for shorter
periods
> of time...
>
> These realizations on my part are due to ignorance: Prasad '84, Baldwin
'87,
> Visser '03, VITA'85 had gone through this reasoning and proposed alternate
> testing methods, like specific consumption, that do predict cooking
> performance. Using the new tests, which establish fuel use at high and low
> power, focused my attention on how low a good stove needs to turn down.
> When lids are used on pots it takes very little wood burning per minute to
> maintain water temperatures just below full boil, around THREE TO FOUR
GRAMS
> PER MINUTE or so depending on stove and pot in my experiments! High power
in
> the Jiko, Three Stone and Rocket uses between 23 to 28 grams of wood per
> minute. (I am using 5 litres of water in my experiments.) The insulated
> stove, by the way, boils the water in about half the time.
>
> As I've said, all of this has been written before, most recently I suppose
> by Visser '03. But reflecting on how little wood is needed for simmering
has
> been instructive for me...
>
> All Best,
>
> Dean

From steve at SUSTAINABLEVILLAGE.COM Mon Aug 18 07:53:43 2003
From: steve at SUSTAINABLEVILLAGE.COM (Steve Troy)
Date: Tue Aug 10 18:30:34 2004
Subject: briquette making workshop
In-Reply-To: <200308180400.h7I40q520194@ns1.repp.org>
Message-ID: <MON.18.AUG.2003.055343.0600.STEVE@SUSTAINABLEVILLAGE.COM>

Dear friends,
I'd like to make sure everyone on this list knows about Richard
Stanley's briquette making workshop in Colorado on September 30th.
http://www.sustainableresources.org/sr2003/pre-conf/stanley.html

Using agricultural waste instead of firewood for heating and cooking
could shift the momentum of desertification, prevent many health and
environmental problems as well as creating many new microenterprises.
Blending it with all the work you've done with stoves could really
increase that benefit. As far as I can tell, Richard has as much or
more experience and knowledge about briquetting as anyone in the
world.
All the best,
Steve Troy
--

===============================================================
The Sustainable Village, LLC 717 Poplar Ave.
Boulder, CO 80304
email: steve@sustainablevillage.com web site:
http://www.sustainablevillage.com
voice 303-998-1323 ext. 100, 888-317-1600 fax 303-449-1348
Sustainable Resources 2003
http://www.sustainableresources.org
"Resources for the Developing World"

From crispin at NEWDAWN.SZ Mon Aug 18 10:24:44 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:34 2004
Subject: Gasifying Newspaper
Message-ID: <MON.18.AUG.2003.162444.0200.CRISPIN@NEWDAWN.SZ>

Dear Tom

>...toplit newspaper gasifier stove. I presume it was natural draft.

Natural draft is all I have! I calculate 3.8 to 4 Pascals total for the
stove (remembering that the input air is heated going downwards so it has to
be subtracted) at the temperatures and moles of gas produced during
combustion.

You commented:
>1 watt blower into the secondary air holes will provide the equivalent
>draft of a 10 foot chimney.

At what temperature is that calculated?

I have worked out that combusted wood (gases) going into the chimney at 275C
and leaving at 175 C gives 17.184 Pascals of draft in a 3 metre chimney.
Does that seem reasonable?

Regards
Crispin

From Carefreeland at AOL.COM Mon Aug 18 17:55:53 2003
From: Carefreeland at AOL.COM (Carefreeland@AOL.COM)
Date: Tue Aug 10 18:30:35 2004
Subject: Gasifying Newspaper
Message-ID: <MON.18.AUG.2003.175553.EDT.>

In a message dated 8/13/03 10:17:23 AM Eastern Daylight Time,
crispin@newdawn.sz writes:

>
> Last Friday night David Hancock (the famous) and I tried cooking on a Vesto
> with newspapers only, meaning they were simply folded and rolled up into a
> hollow tube and lit - no wood, no starters. The idea was to avoid having to
> make a briquette.
>
>
DD Crispin, I take a section of the newspaper and fold then twist itso it
expands back into a 2" small log. Lights and combusts well.
Daniel Dimiduk

From rdboyt at YAHOO.COM Thu Aug 21 17:03:12 2003
From: rdboyt at YAHOO.COM (Richard Boyt)
Date: Tue Aug 10 18:30:35 2004
Subject: Ceramics For Stoves: Finding Clay, Update #2
Message-ID: <THU.21.AUG.2003.140312.0700.RDBOYT@YAHOO.COM>

Stovers:

So, you need clay, but you are miles from a river, stream, lake, or pond, and there are no close road cuts or excavations, and none of the old folk remember where clay used to be dug. So where to look? I picked the center of a gently sloping meadow that had a relatively bare spot where even weeds did poorly. I guessed that the reason might be a layer of clay close to the surface that resisted root penetration.

I am digging a hole about 36 cm (15 inches) deep, and about 30 cm (one foot) across. The first 12 cm (5 inches) was, by volume, largely roots and debris, which, when turned to "soup" and strained, resulted in a strange clay of pudding consistency. The next 25 cm (10") strained out at about half rock and half a clay that looks more promising. I use water to soften the earth and an old truck axle to pry it out. I'm trying for 58 cm (2 feet), hoping to hit more clay and less rock. I made a strainer by stretching some old window screen wire over a large hole cut in the bottom of a much-shortened 5-gallon plastic pail.

A welcome note from Derick Calderon from Guatemala wisely suggested that I could use a hammermill to pulverize the clay clumps and a "normal mixer to stabilize the clay." These would be enormously labor saving if you are preparing large quantities of clay, but for now, I want to use very simple tools that a primitive potter might easily acquire. A sharp stick can dig clay. A clay-lined woven basket can carry water. A shallow pit in the ground can settle out and refine clay. Mosquito netting, cheese cloth, or even an old sock might substitute for screen wire.

I used to break up chunks of raw clay with a cement mixer, using water and fist-sized rocks to tumble the clay chunks into a slurry. Now, I use my hands. Just how many primitive third-world potters have access to a cement mixer? My goal in this series of letters is to find information, and write of what I find in the hope that it might prove useful in underdeveloped countries. Sometimes I forget to keep it simple.

I welcome help in reaching this goal.

Sincerely,

Dick Boyt

 

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From messinger.roth at AFRICA-ONLINE.NET Fri Aug 22 05:00:03 2003
From: messinger.roth at AFRICA-ONLINE.NET (Christa Roth)
Date: Tue Aug 10 18:30:35 2004
Subject: Fw: [STOVES] Ceramics For Stoves: Finding Clay, Update #2
Message-ID: <FRI.22.AUG.2003.110003.0200.MESSINGER.ROTH@AFRICAONLINE.NET>

Dear stovers, just a contribution on clay preparation from Africa, namely Malawi in response to the contribution from Dick Boyt: Here in Malawi most of the potters use the same method of pounding clay than they use for pounding flour: you take a wooden log and pound your (moist) clay heap on the ground until the big lumps are gone and the clay is soft. They usually use an empty maize bag or a mat to prevent the clay mixing with the material form the ground.
Then you sort the clay carefully using your hands and remove all stones and vegetative material. After all the hands are the most sensitive tools you
can use for that. Some other people also pound the clay when it is dry (leaving the clay lumps to sundry previously) and then remove the bigger
particles sifting it through the same sieve they use for the flour. This is a bit more labour intensive, but the sifting is normally done by the
children. Then the sifted clay is wetted and left to 'mature' for 2 or 3 weeks in a pit in the ground before use, keeping it moist all the time by covering it with either old rugs or banana leaves, which are abundant in this area. I was trying to include a picture, showing two women pounding clay, but I learnt that this is not possible on the stoves-listserver. If you want to see the photo, check it out on the Hedon-website http://ecoharmony.net/hedon/howto.php
This all is using purely locally available materials and techniques the women already know very well. We are in the fortunate position to be in an area where clay is readily available and we don't have to dig deep.
Christa Roth, Food Processing and Household Energy Advisor at the Integrated Food Security Programme Mulanje, Malawi, P.O. Box 438 Mulanje (Malawi), Phone + 265 - 1- 466 279, Phone/Fax 466 435,

----- Original Message -----
From: "Richard Boyt" <rdboyt@YAHOO.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, August 21, 2003 11:03 PM
Subject: [STOVES] Ceramics For Stoves: Finding Clay, Update #2
> Stovers:
> A welcome note from Derick Calderon from Guatemala wisely suggested that I could use a hammermill to pulverize the clay clumps and a "normal mixer to
stabilize the clay." These would be enormously labor saving if you are preparing large quantities of clay, but for now, I want to use very simple
tools that a primitive potter might easily acquire. A sharp stick can dig clay. A clay-lined woven basket can carry water. A shallow pit in the ground
can settle out and refine clay. Mosquito netting, cheese cloth, or even an old sock might substitute for screen wire.
>
> I used to break up chunks of raw clay with a cement mixer, using water and fist-sized rocks to tumble the clay chunks into a slurry. Now, I use my
hands. Just how many primitive third-world potters have access to a cement mixer? My goal in this series of letters is to find information, and write
of what I find in the hope that it might prove useful in underdeveloped countries. Sometimes I forget to keep it simple.
> > I welcome help in reaching this goal.
>
> Sincerely,
>
> Dick Boyt
>
>

Christa Roth, c/o Integrated Food Security Programm Mulanje, Malawi
P.O. Box 438 Mulanje (Malawi)
Phone + 265 - 1- 466 279, Phone/Fax 466 435,
cell +265- 8-860 936 (Christa), +265-8-860 937 (Christoph)

From ventfory at IAFRICA.COM Mon Aug 25 04:53:57 2003
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:30:35 2004
Subject: Holey briquette gasifying stove
Message-ID: <MON.25.AUG.2003.105357.0200.VENTFORY@IAFRICA.COM>

Greetings to all stovers

Please visit the stove pages to view our holey briquette gasifier report and accompanying diagram (We really owe Tom a sincere thanks for his help in putting it up). http://www.repp.org/discussiongroups/resources/stoves/

This report is open to anyone interested to comment and replicate for their own testing and feedback. The stove design will ultimately revolve around the physical shape and blend of the briquette that is being used and would have to be altered somewhat to suite other types of briquettes. We are not looking into the continuous feed aspect for now, nor is the top pot holder being pursued in depth at this time but these are considerations for the future once we get the "gasification-only" design established and fully tested.

Once we get started on working prototypes we will send pictures and progress reports to the list for comment as well. We apologise for the lack of pictures at this point.

Further details can be obtained from the report or from Richard Stanley rstanley@legacyfound.org

Regards

Kobus Venter

From rdboyt at YAHOO.COM Tue Aug 26 22:04:14 2003
From: rdboyt at YAHOO.COM (Richard Boyt)
Date: Tue Aug 10 18:30:35 2004
Subject: Practical Tips For Potters Making Improved Cooking Stoves
Message-ID: <TUE.26.AUG.2003.190414.0700.RDBOYT@YAHOO.COM>

Practical Tips For Potters Making Improved Cooking Stoves, Part 4-- Materials That Can be Added to Make a Better Mixture.

The following material is the fourth part of a condensation from the booklet "Practical Tips For Potters Making Improved Cooking Stoves" Prepared by Tim Jones, Illustrated by Debbie Riviere. Published by Hofman Systems Engineering b.v., PO Box 642, 3100 AP Schiedam, The Netherlands (1993).

"A very sandy clay found alongside a plastic clay would be ideal, but usually sand as a separate ingredient has to be added. Sand opens up the clay to allow it to dry more evenly to prevent cracking. The only problem with sand is that it consists of silica, which goes through a process called the 'silica or quartz change.' This means that the sand grains expand quite suddenly as they get heated in the kiln, then shrink again at the same temperature as it cools down. If too much sand/ silica is in the mixture, cracks can occur during firing.

"Sieved fine sawdust, if added to a clay mixture, will do four things: it will open up the clay (make more pores), and help with the drying process by allowing the water to leave the drying stoves more easily and evenly. The sawdust burns out during the firing, and so increases the porosity of the fired clay, which is an advantage, as long as it is not too much and weakens the stove.

"The addition of rice husk or rice husk ash has been found to really help with the strength and durability of fired clay stoves. It is often preferable to [use] sawdust, if a choice is available.

"Grog is the name for fired clay that is crushed down to a powder and sieved. It helps the stoves to dry more evenly, without the problem of the 'silica change' that comes with the use of sand. It is a good use for broken pots that would otherwise be wasted. Other things that have proved to be good when added to the clay mixtures used to make cooking stoves are charcoal dust and any sieved ash.

My reactions to the above quotations from "Tips for Potters":

1: Sand, as an addition to a clay body can be a mixed blessing, and can be overdone. It certainly reduces plasticity, and poses the problem of a rather sudden two percent expansion at about 590 degrees C (1,100 F) as the temperature rises. As the clay cools, there is an equal contraction at the same temperature, so passing either way through this temperature should be done slowly. The problem is that thick sections of clay do not heat evenly, or cool evenly, and so internal stresses can build up that can cause fractures to occur, sometimes well after the finished clay object has been put into service.

2: Not having access to rice husks, or its ash, I've never tried it, but I have used shredded newspaper, shredded corrugated cardboard, and various sizes of sawdust and charcoal. Of them all, charcoal is the only one that does not shrink as it dries. This can be an advantage in arriving at a clay mix with relatively low drying shrinkage. The size of the charcoal particles may be an important variable. Dean Still says it should be very fine, but that breaks the cell walls of the wood that had been made into char. If the cell wall is lost, the cell itself could fill with clay. A coarse char might prove to provide more air pockets in the finished product.

3: Grog is a very good addition to the clay mix, but does not necessarily reduce the problem of silica expansion/ contraction, if the grog itself contained an excess of sand, which may be why the pot it was made from cracked in the first place.

Hope this makes sense. There's a lot I don't know, but I'm gaining on it!

The next entry, Part 5 will probably be "Mixing Up Clay Mixtures and Testing Them".

Dick Boyt

 

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From rdboyt at YAHOO.COM Tue Aug 26 22:05:47 2003
From: rdboyt at YAHOO.COM (Richard Boyt)
Date: Tue Aug 10 18:30:35 2004
Subject: Ceramics For Stoves: Drying Formed Clay Shapes
Message-ID: <TUE.26.AUG.2003.190547.0700.RDBOYT@YAHOO.COM>

Ceramics For Stoves: Drying Formed Clay Shapes

Stovers:

Just how and why does plastic clay change as it dries? I know just enough to know that I don't know very much.

Books tell me that tiny particles of clay are a bit like playing cards. In a loose scattered stack, these platelets interlace and, if lubricated with water, easily slide over each other. This is why clay can take and hold most any shape you give it. This property is generally called "plasticity". Dry the clay by removing the water, and the particles can no longer slide. The drying clay now becomes hard and rigid, and loses its plasticity. Tests I have recently made indicate that clay shrinks quite steadily as it dries. As long as it retains its plasticity, rapid uneven drying does not present a serious problem. However, as the clay loses plasticity, care must be taken to dry it evenly, to prevent shrinkage stresses that can cause fractures in the clay to occur. As long as all portions of the clay remain plastic, you can safely air dry. Drying evenly usually means slow drying. This is particularly important if an object made of clay has great differences in thickness. Outside surfaces
tend to dry faster than inside surfaces. Thin sections tend to dry more quickly than thick sections. Top surfaces tend to dry faster than bottoms.

If you want to dry clay evenly, it is hard to beat putting it inside a polyethylene plastic grocery bag with just a bit of an opening at the top, well above the top of the clay. As water evaporates from the surface of the clay, it cools and dampens the air in the bag surrounding the clay. The cool damp air sinks, filling the plastic bag. The slightly open top permits a very slow air exchange with warmer, drier outside air, and so the clay dries and shrinks slowly, evenly, and thus with minimal stress. After the clay has dried enough to loose plasticity, and to change to a lighter color, you can usually finish drying it in the open air.

So just how long should it take to dry a clay shape? It depends upon the size, the shape, and the thickness of the clay object. The temperature and humidity of the air, the openness (porosity) of the clay, the size and position of the hole at the top of the plastic bag, and just how much water the clay holds. How do you know when its dry? The most obvious clue is when it becomes hard enough to resist a fingernail impression, and it changes color, usually becoming a lighter shade. A typical coffee cup shape might safely dry in a day or two. A 3" diameter solid clay ball might take a week or two.

If, in spite of all your efforts, for whatever reason, your clay fails, as long as it hasn't been fired, you can reclaim it by re-mixing with water, and start over.

 

Good luck!

Dick Boyt

 

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