November 1999 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 btremeer at dds.nl Fri Apr 2 10:08:31 1999
From: btremeer at dds.nl (Grant Ballard-Tremeer)
Date: Tue Aug 31 21:36:17 2004
Subject: Household Energy Development Organisation's Network
Message-ID: <000501be7d1a$e49bf3c0$2f0deed4@blackthorn>

Dear Stovers

I'm writing to introduce a new Internet resource for development
organisations. It's called the Household Energy Development Organisation's
Network (HEDON). As the name implies it aims to link organisations working
in household energy: in such fields as housing and kitchens, forestry for
fuel, health and air pollution, cottage industries, policy, social impacts,
and naturally, cooking stoves.

HEDON is an informal consultative forum dedicated to improving social,
economic, and environmental conditions in the South, through promotion of
local, national, regional and international initiatives in the household
energy sector and has been in existence for over 9 years. The Internet part
of the network makes two electronic resources available: a homepage at
http://www.energy.demon.nl/hedon/ and an email list. Membership of the email
list will put your organisation in touch with a growing group of like-minded
organisations world-wide. In addition you will receive a monthly email
newsletter. In order to join you should be:
* working in the field of household energy (with interest in environment,
health, technical development, dissemination, etc.)
* involved with less developed countries, urban and rural; and,
* involved in research, policy, or development work.

The email list can be joined by filling in the form on the WWW (surf to
http://www.energy.demon.nl/hedon/ and select "Join the network").
Alternatively send a message to hedon@energy.demon.nl requesting information
on how to join and I will email the form to you.

With best wishes
Grant

-------------------
Grant Ballard-Tremeer
btremeer@dds.nl; http://www.energy.demon.nl
-------------------

Stoves List SPONSORS and ARCHIVES:
http://solstice.crest.org/renewables/stoves-list-archive/
Stoves Webpage
http://www.ikweb.com/enuff/public_html/Stoves.html
For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From Alex.English at adan.kingston.net Fri Apr 2 20:58:30 1999
From: Alex.English at adan.kingston.net (*.english)
Date: Tue Aug 31 21:36:17 2004
Subject: Conference in 2000
Message-ID: <199904030158.UAA05263@adan.kingston.net>

Dear Stovers,
An announcement of the International Conference on Biomass based Fuels
and Cooking Systems has been posted on the Stoves Webpage. A link to
it can be found in the NOTICE section, just below the NEW section.
The link will remain there until the after the conference.

Alex

Alex English
RR 2 Odessa, Ontario, Canada
K0H2H0 613-386-1927
Fax 613-386-1211
Stoves List SPONSORS and ARCHIVES:
http://solstice.crest.org/renewables/stoves-list-archive/
Stoves Webpage
http://www.ikweb.com/enuff/public_html/Stoves.html
For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From larcon at sni.net Sun Apr 4 01:08:51 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:17 2004
Subject: Topic 3. Efficiency measurementss
Message-ID: <v01540b03b318dfdbeffe@[204.131.233.48]>

Stovers: In this note I want to describe efficiency measurements on both
typical traditional stoves and of the new improved stoves they are adding.
These were performed by some associates (and sub-contractors) of
Rogerio/Prolena and were done for the Nicaraguan Department of Energy to
establish a base line for the country. I was not actually present for all
of either of the two measurements made while therw, but I think the
following was fairly accurate and Rogerio can still get definitive answers
on technique without difficulty. He has also promised a report to the
group on the efficiencies found after the tests are further along.

I am mainly writing about this to start a dialog on standardization
of tests - and some of this is to see if anyone wants additional data
collected..

1. Equipment The test equipment for any efficiency measurement
is pretty easy to obtain and their's all seemed standard - needing mainly a
scale for weighing wood and water.
a. weight scales. The first day they used an eletric-powered
accurate laboratory-type scale - possible because there is such widespread
availability of electricity in Nicaragua. However, it failed on the second
day and they borrowed a less accurate market type scale - undoubtedly
losing some accuracy - but this is not a long term measurement problem.
b. liquid measure. Used for approximate measures, but weight was
the reported measure for both wood and liquids.
c. temperature. I didn't look closely, but presume these were
standard laboratory thermometers.
d. Time - I believe temperature at each of two pots was monitored
every five minutes while coming to a boil and then every ten minutes.
Several other temperature measurements were made of various stove and
chimney surfaces at the same times.

e. Technique - After the (previously measured weights of) wood
were essentially consumed and I think as pot temperatures were beginning to
decline, the remaining water was weighed for each pot and then the weight
of all remaining hot charcoal and ashes were weighed together (not an easy
task).

I am presuming that they will use standard formulas for calculating
the efficiency and that Rogerio will share those with us as he reports the
results later.

Questions - Q1. There was no measuement made (nor was one likely to be
easy) on the moisture content of the wood (which had been purchased in the
local market and was likely to be roughly the same for each stove tested).
Does any list member think this is a major defect in the testing protocol
and how should it be rectified?

Q2. Should the researchers have asked the regular users of the
stove to do the tests, so as to include this variable in their results?
And Why?

Q3. Should any one stove have several different tests - so as to
average out such variables as wind speed, etc.?

Q4. The air quality tests were conducted on these two stoves were
conducted with regular cooking and the regular cook (I can't remember
whether the same type of wood, but certainly a different and I believe an
unmeasured amount at a different time (with techniques in the next note).

Q5. Has anyone seen an extensive report on the importance of these
or any other specific variable when measuring the efficiency of such large
heavy stoves (which will be defined more thoroughly later)? Again, the
intent of this note is to help Rogerio and the researchers do the most
meaningful tests.

2. Standardized pan dimensions. Two new aluminum pans of
different sizes were used for the tests, with tare pot weights and amounts
of water that I don't now have, but which were of course recorded. I
presume that these same two pans will be used for all tests. The tests were
conducted with tops on each pot. (In the past, when I have used water
quantity evaporated as a means of determining efficiency, I have always
kept the top off.).

Does anyone care to comment on a recommended standardization
procedure for how full each pot should be and/or on how the pot sizes might
effect the eventually stated efficiencies?
Does the above matter if the tests are essentially the same at all
sites?

I took notes on stove dimensions at each site and there was a
considerable variation. I left these with Rogerio and presume the
researchers will continue getting these. At this time, I think they are
mostly trying to get a baseline and not yet to try to fix each up better
(the subject later this week).

Stovers: Any other questions or comments on things that are really
important to look out for in these efficiency tests? Thanks in advance.

Rogerio - please translate this for Leonardo and Rosaria. I now
wish I had taken better notes and had stayed throughout at least one full
efficiency test and that I had a chance to see the computations. I may
have left out a lot of important steps that they will wish to add to.
Please wish them good luck in their further tests.

Ron

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

From larcon at sni.net Sun Apr 4 01:08:53 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:17 2004
Subject: Topic 4. Pollution measurements
Message-ID: <v01540b04b318e1474583@[204.131.233.48]>

Topic #3 (on efficiency) was written a long time ago. This one (and as
many more as I can will be done in a rush as I head off tomorrow (Alex
taking over again). I apologize for the rush - caused by being hugely
involved in fighting a new TV tower down the road. Fortunately, I ad made
an outline a long time ago, so I at least have some idea of what I wanted
to write about.

I hope that a dialog can go on in my absence - as I will try to
give some more report on stoves in Ethiopia in about a month

Stovers:

1. Equipment being used. Rogerio's contractor is using two
measures: 1) a CO meter that was monitored periodically
2) a filter with pump that was run for 1.5 hours. The filter was weighed
before and after each test (used just once of course).

Both of these tests were run twice - with and without the stoves
being operated.

As I said in the last one - these were not done at the same time as
the efficiency measurements.

The exact equipment can be provided later, but appeared to be of
high quality - and came from a University setting.

2. need for a standard distance?

There didn't seem to be any standard distance employed. Has anyone
ever proposed such a distance (such a a few meters, which was the
approximate distance used)?

3. need for a standard height.

Both measurements were at about eye height, with the same tripod
holder used for all tests. Any recommendations?

4. How should wind be handled?

I don't believe that this was treated uniformly (I saw about 4
tests). The wind was gusty, and from several directions - but I believe
could have been a big feature. Is it perhaps best to be down wind as best
one can?

Stovers: Any questions on this topic?

Ron

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

From larcon at sni.net Sun Apr 4 01:08:57 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:17 2004
Subject: Topic 5. Chimney valves
Message-ID: <v01540b05b318e18052e6@[204.131.233.48]>

Stovers: My (very brief) thoughts on chimney valving:

1. Not being installed. The new stoves that I saw being tested
did not have any chimney valving to allow control of the chimney draft. I
have seen leterature saying this is an important stove control variable and
should always be used.

Anyone able to give an authoritative answer?

2. John Gulland theory. I believe John Gulland feels that it is
better to control the primary air supply to minimize turbulence within the
chimney. But I never saw any control there either.

Any support or disagreement with John?

3. Too much or too little draft? In general there seemed to be
two sections (2 meters I think) of concrete sewer pipe for the chimney. In
some cases, this barely made in through the roof. I think it was about 15
cm ID

Anyone have a favorite means of determining appropriate length?

4. What size?

Are the above dimensions OK - can it be smaller ID to drop the costs?

Stovers: Any questions?

Ron

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

From larcon at sni.net Sun Apr 4 01:09:02 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:17 2004
Subject: Topic 6. Height reduction under pot #2
Message-ID: <v01540b06b318e20471ee@[204.131.233.48]>

Stovers:
The typical newly constructed Nicaraguan stove that I saw did not
have the usual reduction under the second pot that I see in the literature
(although some did).

1. Experience in testing. By the time I left, there were no
efficiency measurements to report, so I can't tell if Rogerio and Leonardo
have seen the impact of this construction "failure". However, this is an
easy and no-cost fix to make, so there is no permanent harm.

2. Any analysis or experiments seen? This seems like a likely
topic for some good past experiments - but I can't remember seeing this
topic in data form. Anyone want to report on the best height under both
the first and the second pot?

3. Reason for the test program: Although the height reduction
should have been there, I applaud Rogerio for getting the funds to go out
to check on how well installation had actually occurred by the various
implementing NGOs around Managua (all trying mostly to improve air
quality).

Stovers: Any other questions or comments for Rogerio?

Ron

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

From larcon at sni.net Sun Apr 4 01:09:14 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:17 2004
Subject: Topic 9. Hoods
Message-ID: <v01540b09b318e2738c1f@[204.131.233.48]>

Stovers: To get high stove efficiency, it appears that one needs to get the
flame and/or combustion gases passing vertically past the pots - not
horizontally under (a small part of) them. This is the approach put forward
by Approvecho in the rocket stove, by shielded open flames and those of us
working on the Charcoal making stoves (CMS).

However this attempt to avoid a chimney can lead to poor air
quality (no good test data yet on the CMS). One possible way to get both is
to use a venting hood over the cookpot. I don't recall any discussion on
this list, nor do I remember reading anything about the general subject of
venting hoods. I wonder if any list member has any experience with them
and when they are best to be employed.

In Nicaragua I saw hoods in use in several indoor barbecue chicken
establishments. They were doing a partial, but not complete, job, as smoke
still sometimes was engulfing the cook - and sometimes the customers. They
are used in many American kitchens for both electric and gas cooking - to
remove cooking odors - almost always with a fan (which we probably want to
avoid in most cases). With the much lower temperatures available and much
cold air entrainment, is it impossible to get sufficient draft to do a good
job of venting?

Any experts on the list on this topic?

Ron

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

From larcon at sni.net Sun Apr 4 01:09:07 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:17 2004
Subject: Topic 7. Plancha issues
Message-ID: <v01540b07b318e23d7f62@[204.131.233.48]>

Stovers:

1. Definition. I think "plancha" means the steel cooking surface.
. Rogerio's experience in Honduras showed a great preference for replacing
the usual two hole design with a sizeable piece of steel. This was heated
from below by the combustion gases and followed immediately by the stove
pipe (no cook pot holes typically, but one or more cook pot holes could
also be used.

2. advantages 1). The cook pot does not get dirty.
2) One can cook certain foods directly on the "plancha"

3. Disadvantages 1) The large heated surface is not all used and
the area is not controllable - kleading to some inefficiencies. 2) It
adds extra costs.

4. Preference - tradeoffs? Has anyone looked at the differences
at all closely? When should the Plancha type stove be recommended? Should
hot gases come up past the metal plate as opposed to going laterally past
it?

5. Dean Still (28 March) and Ted Keller (20 March) have much more
knowledge than I in these stoves and have spoken authoritatively. However,
thre may be others who wish to jump in.

Stovers: Any more?

Ron

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

From larcon at sni.net Sun Apr 4 01:09:11 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:17 2004
Subject: Topic 8. Volcanic material
Message-ID: <v01540b08b318e25885c7@[204.131.233.48]>

Stovers: This topic on using a light weight lava stone. I saw this being
very widely used in Managua - for building walls and yard enclosures.
There was a considerable awareness of earthquakes in Nicaragua, so after
several layers, there was a layer of steel-reinforced concrete. Elsen
Karstad has recently reported something similar being used in Kenya. It
seems not to be used in Nicaragua for stoves (Rogerio did not remember ever
seeing it used).

1. Appearance. This looks outwardly like any heavier stone or
(the smaller) cast concrete block. The typical color was gray - some were
a little tan. One could see the the circular saw marks used to cut them
out of the mountain.

2. Size. Every unit I measured was 60 by 40 by 13 cm. I think
when a smaller one was needed (as on the corner of a building it was
chiseled out of a larger one. I only saw a few which might have been 40 x
40 X 13.

3. Cost. They were a little under $1.00. This seems to be
cheaper than anything else - based on its widespread use.

4. Use in stoves. I think the volcanic material has great
potential in stoves. But maybe I am wrong. Has any list member any more
data to report? The thermal resistance characteristics? The lifetime
under elevated temperatures?

Ron

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

From larcon at sni.net Sun Apr 4 01:09:23 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:17 2004
Subject: Topic 11. Rocket stove * 2 (with blocks)
Message-ID: <v01540b0bb318e2b99c85@[204.131.233.48]>

Stovers:

In previous notes I have mentioned the possible use of volcanic
blocks, and the efficiency advantage of the Approvecho "Rocket" stove and
of using parallel flues (rather than series) for cooking with two pots.

In fooling around with these ideas on my last day with Rogerio, I saw
a way of using two of the insulative blocks on the sides, with a few bricks
as spacers to create two parallel chimneys with a firebed on another two
volcanic blocks underneath for the fire to sit on. These could be
separated laterally by maybe 10 cm to allow a grate and better (and maybe
controllable air flow to the combustion zone. Wood could be fed in from
either or both ends.

Sorry I don't have a means at this late date of getting a diagram
in to Alex - but maybe Rogerio could try it and send it on for others if it
seems to work. Bricks could be used instead - but the cost would go up. As
Dean Still points out, there is an advantage in using less material and
this doesn't use much.

This should act something like two Rocket stoves in parallel with a
single combustion zone. The two metal parts of the Rocket stove would be
replaced by the solid insulating blocks/bricks. If one wanted only a
single pot to be in use, you could close up either of the two chimneys with
a top "brick".

If combustion wasn't clean enough - maybe a hood?

Just an idea. Any comments?

Ron

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

From larcon at sni.net Sun Apr 4 01:09:27 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:18 2004
Subject: Topic 12. New Charcoal-making stove ideas
Message-ID: <v01540b0cb318e2e8a7a2@[204.131.233.48]>

Stovers:

Rogerio felt I should give a demonstration of Charcoal-making
stoves (CMS) while in Managua, so on my last day I did talk (Rogerio as
trannslator) to about 10 stove workers who Rogerio had brought together.
I decided to not bring any of my old cans down, but rather see what could
be made locally

About two weeks before the talk, before even meeting Rogerio, I
went to the local market as a tourist and found locally-made, scrap-steel
charcoal burners with legs selling for about 25 cordovas ($2.25). Armed
with some instructions I went to try to find the maker - and eventually
found another person who thught he could make my sketch for something the
same size for 100 cordovas (I thought).

With Rogerio to help in picking it up, and bargaining by Rogerio,
the final price was kept at only 200 cordovas - $18 . This was fairly good
looking, (and the first time I had legs - albeit shorter than I thought I
had ordered) ). I think that with competition, it should be in the $5.00
range.

2. Because I wanting to work some with the volcanic material, I
bought one large block (less than $1.00) and tried some "chiseling" through
the 13 cm dimension, which seemed like enough to get enough draft. I was
planning on just using an ordinary can below for the fuel/pyrolysis zone.

Unfortunately, because I chose a block with a pre-existing crack
(just being dumb), the block didn't make it all the way through my first
clumsy attempts. Still, I'm sure that with the right hole-drilling tools,
it can be worked as well as the techniques used to get the slabs at such
low cost.

This material needs more work that I hope someone will try, It is
not often that I see tough, cheap, light-weight material like this.

3. Old (free) cans. Rogerio's supply of old cans wasn't too great, but he
had some short ones that I thought would work to display to Rogerio my
usual techniques with baling wire or "strap" means of holding the cans a
bit apart to get the right amount of secondary air in. However, instead I
thought of using a pair of pliers to crinkle the sides of the can a bit to
be able to force one inside the other. (Better tools are available for the
crinkling than pliers)

By doing this twice, I was able to get a longer chimney with one of
the "joints", but more importantly to nicely get the secondary air in at
the lower "joint" . In retrospect, I should have tried for a little more
secondary air - but the idea basically worked.

4. concrete blocks. Because I was wandering around several construction
sites looking at the volcanic block, and because we had a chance at one
efficiency test site to try a quick test, I eventually got Rogerio to buy
two concrete blocks ($.55-60 cents each). The secondary air supply was
created by 3 large nails separating the blocks (pebbles could have been
used). The primary air control was achieved by using a stick and moving
dirt/sand undernerth the lower block.

I think concrete blocks may have also have some potential for
cracking off pieces of fuel wood at the correct length. Before thinking of
that, I usd a small hatchet and I prepared all the wood for the three
next-day tests from wood trimmings Rogerio had lying around.

5. Actual test. We started them in the order described about (#1, #3,
#4). The last two didn't light as well as I am used to but eventually all
had a fairly good flame and some controllability. None went to completion
- as I choked of the pyrolysis at the end of the "lecture" (really a
demonstration), rather than at the end of the burn. Some charcoal was
obvious for all three cases - but the quality had not been too good (I
wasn't happy with my grates for any of the tries). There was a bit more
smoke tha I would have liked but all three burned moderately cleanly, A
small amount of water came to a boil quickly enough - no efficiency or
pllution tests performed.

So there is nothing really new to report on CMSs, but I have two
new approaches to try some more (and I would like to work more with the
volcanic material as well - but too far away from having a good source).

End of the Nicaragua series . Again - sorry for delaying and then
having to hurry. Hope to have some ideas and answers waiting for ame in a
month. I don't have time to reread all - so please accept my apologies for
the may typos I am sure are in,

Ron

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

From larcon at sni.net Sun Apr 4 01:09:17 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:18 2004
Subject: Topic 10. Series vs parallel
Message-ID: <v01540b0ab318e29493b4@[204.131.233.48]>

Stovers:

The Lorena stove (and almost every other two-burner stove I have
seen) uses a series approach rather than a parallel approach. This was
common in Nicaragua.

I remember reading something (probably from an Eindhoven report)
pointing otr the benefits of doing the two burners in parallel rather than
in series (higher efficiency as well as better control). I seem to recall
someone else saying this recently on this list but can't find it now.

Can anyone remember seeing this and can they find a way to get the
original (or others) to Alex for the web page?

Does anyone have data to prove or disprove this>

Is it perhaps better to use two separate stoves - or (as in next
message) to perhaps have one fire and two updrafts going to the two
separate pots?

Ron

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

From larcon at sni.net Sun Apr 4 10:38:47 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:18 2004
Subject: Topic 9. Hoods
Message-ID: <v01540b01b32d2b8e188b@[204.131.233.37]>

Maybe my last effort at home to send this on (and a few more like it).
Please don't send anymore to me. See you all in a month. Ron

>Date: Sun, 04 Apr 1999 05:39:20 -0300
>From: Kevin Chisholm <kchishol@fox.nstn.ca>
>MIME-Version: 1.0
>To: "Ronal W. Larson" <larcon@sni.net>
>Subject: Re: Topic 9. Hoods
>
>Dear Ronal
>
>Ronal W. Larson wrote:
>
>del...
> However this attempt to avoid a chimney can lead to poor air
>
>> quality (no good test data yet on the CMS). One possible way to get both is
>> to use a venting hood over the cookpot. I don't recall any discussion on
>> this list, nor do I remember reading anything about the general subject of
>> venting hoods. I wonder if any list member has any experience with them
>> and when they are best to be employed.
>>
>> In Nicaragua I saw hoods in use in several indoor barbecue chicken
>> establishments. They were doing a partial, but not complete, job, as smoke
>> still sometimes was engulfing the cook - and sometimes the customers. They
>> are used in many American kitchens for both electric and gas cooking - to
>> remove cooking odors - almost always with a fan (which we probably want to
>> avoid in most cases). With the much lower temperatures available and much
>> cold air entrainment, is it impossible to get sufficient draft to do a good
>> job of venting?
>
>Hoods inherently cannot help the basic combustion, in that the draft effect
>which they generate cannot be transmitted to the combustion zone.
>
>There are two kinds of smoke from a cooker: Combustion smoke, and cooking
>smoke.
>Gernerally, combustion smoke is not wanted, because it is a result of poor fuel
>efficiency. However, it may be wanted for flavor effects. Cooking smoke can be
>far more significant in volume than combustion smoke. In general, it is always
>possible to vent combustion smoke, but cooking smoke may be so much in
>quantity,
>and so low in temperature, that there is insufficient residual heat to cause it
>to be drawn away by a gravity hood. Note also that many cooking hoods have a
>grease filter to reduce grease fallout in the vent stack, and a very real fire
>hazard. Filter design can have a very significant effect on the ability of a
>natural draft stack to take away combustion and cooking fume. Now here is a
>significant conflict: A gravity stack with a suitable grease filter may
>not work
>adequately, but it may work adequately if the grease filter is removed. The
>problem here, of course, if the fire hazard created. Cooking hood and stack
>design is not at all a trivial matter, because of the fire consideration. Many
>Jurisdictions specify stainless steel ducting for cooking hood exhaust because
>of the fire hazard. Fires can happen is third world countries just as
>readily as
>in the first world. Most likely, an exhaust fan will be required to overcome
>grease filter resistance.
>
>Note also that many restaurants in conler countries have insufficient make-up
>air, in an efort to save on winter energy heating. The effect is to put the
>building under suction. Perhaps you have been to a restaurant and noticed that
>the door was difficult to open? The same effect can occur in hot climates,
>where
>the make-up air system is choked or insufficient, to save on air conditioning
>load. (Make-up air must be supplied to the building to replace that which is
>drawn out by the venting system.) The problem can be very real and not
>intuitively obvious in a gravity venting system: with the doors and windows
>closed, the very meagre gravity ventillation system hasn't got a hope of
>adequately removing cooking and combustion fume.
>
>Kindest regards,
>
>Kevin Chisholm

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

From larcon at sni.net Sun Apr 4 10:40:11 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:18 2004
Subject: Topic 8. Volcanic material
Message-ID: <v01540b02b32d2bf02f77@[204.131.233.37]>

Same intro. Kevin has helped . Thanks. Ron

>Date: Sun, 04 Apr 1999 05:39:29 -0300
>From: Kevin Chisholm <kchishol@fox.nstn.ca>
>MIME-Version: 1.0
>To: "Ronal W. Larson" <larcon@sni.net>
>Subject: Re: Topic 8. Volcanic material
>
>
>
>Ronal W. Larson wrote:
>...del...
>
>> 4. Use in stoves. I think the volcanic material has great
>> potential in stoves. But maybe I am wrong. Has any list member any more
>> data to report? The thermal resistance characteristics? The lifetime
>> under elevated temperatures?
>
>I would suggest that the relevant properties are:
>
>1: Thermal conductivity
>2: Melting point
>3: Thermal mass
>4: Spalling tendancy. (Note: "When "dry" this lava may not spall, but it may
>absorb water if left out in the rain. If the initial fire is a fast hot one,
>absorbed water may cause cracking or spalling, or even a small steam
>explosion.)
>5: Thermal expansion characteristics over its expected operating range.
>6: Chemical reactivity: Usually, light colored lavas are high is silica, ie,
>"acid" and dark colored lavas are high in iron, calcium and magnesium.
>("basic") Depending on lava chemistry, stove operating temperatuer, and ash
>chemistry, there may be a tendancy for the ash to flux the lava.
>
>Kindest regards,
>
>Kevin Chisholm

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

From larcon at sni.net Sun Apr 4 10:40:58 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:18 2004
Subject: Topic 5. Chimney valves
Message-ID: <v01540b03b32d2c4242cf@[204.131.233.37]>

Ditto intro.

>Date: Sun, 04 Apr 1999 05:39:35 -0300
>From: Kevin Chisholm <kchishol@fox.nstn.ca>
>MIME-Version: 1.0
>To: "Ronal W. Larson" <larcon@sni.net>
>Subject: Re: Topic 5. Chimney valves
>
>
>
>Ronal W. Larson wrote:
>
>> Stovers: My (very brief) thoughts on chimney valving:
>>
>> 1. Not being installed. The new stoves that I saw being tested
>> did not have any chimney valving to allow control of the chimney draft. I
>> have seen leterature saying this is an important stove control variable and
>> should always be used.
>>
>> Anyone able to give an authoritative answer?
>>
>> 2. John Gulland theory. I believe John Gulland feels that it is
>> better to control the primary air supply to minimize turbulence within the
>> chimney. But I never saw any control there either.
>>
>> Any support or disagreement with John?
>
>In that most such systems have marginal to insufficient draft under the best of
>conditions, I would suggest no valving on the stack, and that the rate of
>burn be
>controlled by control of inlet air.
>
>Note that it is vitally necessary to hare EITHER a primary and secondary
>control
>OR to have such a primary-secondary air split engineered into the basis system
>design, with the one air valve controlling primary and secondary air.
>
>> 3. Too much or too little draft? In general there seemed to be
>> two sections (2 meters I think) of concrete sewer pipe for the chimney. In
>> some cases, this barely made in through the roof. I think it was about 15
>> cm ID
>
>Too much draft can be controlled readily by restricting air inlet. Too little
>draft is a serious problem.
>
>> Anyone have a favorite means of determining appropriate length?
>
>The length has to be such that the desired burning performance is attained. The
>best way, I feel, would be empirical.
>
>> 4. What size?
>
>> Are the above dimensions OK - can it be smaller ID to drop the costs?
>
>Basically, the stack has to be tall enough to get through the roof, as a bare
>minimum requirement. Then preferably, at least a meter above the roof, to
>minimize variability in performance due to wind direction. Preferably, it
>should
>be above the ridge of the roof.The diameter is dependant on height, and desired
>fuel burn rate. If the height is preselected from house considerations, the
>diameter will probably be determined relatively easy from practical
>considerations: if pipe is used, a "tall height" intuitively requires a bigger
>diameter. A 4" pipe (10 cm) to a height of 12 feet would look skinny and
>inappropriate, and people would intuitively install a 6" or 8" pipe. These
>generalities are not much help specifically, but there are too many
>variables to
>calculate a "minimum required diameter.
>
>Kindest regards,
>
>Kevin Chisholm
>
>>
>>
>> Stovers: Any questions?
>>
>> Ron
>>
>> Ronal W. Larson, PhD
>> 21547 Mountsfield Dr.
>> Golden, CO 80401, USA
>> 303/526-9629; FAX same with warning
>> larcon@sni.net
>>
>> Stoves List SPONSORS and ARCHIVES:
>> http://solstice.crest.org/renewables/stoves-list-archive/
>> Stoves Webpage
>> http://www.ikweb.com/enuff/public_html/Stoves.html
>> For information about CHAMBERS STOVES
>> http://www.ikweb.com/enuff/public_html/Chamber.htm
>

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

From larcon at sni.net Sun Apr 4 10:42:38 1999
From: larcon at sni.net (Ronal W. Larson)
Date: Tue Aug 31 21:36:18 2004
Subject: Kevin's fourth Re: Topic 4. Pollution measurements
Message-ID: <v01540b04b32d2c6f4d58@[204.131.233.37]>

Kevin thanks for four very thoughtful response - that I skimmed only.
Anyone else? Ron

>Date: Sun, 04 Apr 1999 05:39:42 -0300
>From: Kevin Chisholm <kchishol@fox.nstn.ca>
>MIME-Version: 1.0
>To: "Ronal W. Larson" <larcon@sni.net>
>Subject: Re: Topic 4. Pollution measurements
>
>Dear Ronal
>
>I am not sure that I totally understand your setup, but I would suggest that
>the only meaningful test for pollution would be at a point equivalent to the
>end of the flue, just before the gases leave the system. If there is not the
>equivalent to a "end of stack", then one should be made, if only for test
>purposes.
>
>With a stack of known area, one has the potential to get a meaningful
>indication of pollution concentration. Knowing the temperature, area, and
>velocity, one can then calculate the weight of pollutants emitted, in relation
>to the fuel being burned, and in relation to the heat being liberated.
>
>Taking a sample "upwind" will give perfect indicated results, regardless of
>actual results. The downwind sample can also be equally meaningless..... simply
>sample the area slightly above or slightly below the pollution plume to get
>perfect indicated results..
>
>In the case of an "open top cooker, that does not normally have a stack, I
>would suggest that one must be made to funnel the off-gases to a consistent
>sample point. In this case, the results could be marginally better than
>actual, in that the suggested "test stack" would marginally help the draft.
>However, the potential error here would be far less significant than a "no
>stack" sample. It would be far less prone to manipulation of the placement of
>the sample point to get good indicated performance.
>
>Kevin Chisholm
>
>Ronal W. Larson wrote:
>...del...
>
>> 1. Equipment being used. Rogerio's contractor is using two
>> measures: 1) a CO meter that was monitored periodically
>> 2) a filter with pump that was run for 1.5 hours. The filter was weighed
>> before and after each test (used just once of course).
>>
>> Both of these tests were run twice - with and without the stoves
>> being operated.
>>
>> As I said in the last one - these were not done at the same time as
>> the efficiency measurements.
>>
>> The exact equipment can be provided later, but appeared to be of
>> high quality - and came from a University setting.
>>
>> 2. need for a standard distance?
>>
>> There didn't seem to be any standard distance employed. Has anyone
>> ever proposed such a distance (such a a few meters, which was the
>> approximate distance used)?
>>
>> 3. need for a standard height.
>>
>> Both measurements were at about eye height, with the same tripod
>> holder used for all tests. Any recommendations?
>>
>> 4. How should wind be handled?
>>
>> I don't believe that this was treated uniformly (I saw about 4
>> tests). The wind was gusty, and from several directions - but I believe
>> could have been a big feature. Is it perhaps best to be down wind as best
>> one can?
>>
>> Stovers: Any questions on this topic?
>>
>> Ron
>>
>> Ronal W. Larson, PhD
>> 21547 Mountsfield Dr.
>> Golden, CO 80401, USA
>> 303/526-9629; FAX same with warning
>> larcon@sni.net
>>
>> Stoves List SPONSORS and ARCHIVES:
>> http://solstice.crest.org/renewables/stoves-list-archive/
>> Stoves Webpage
>> http://www.ikweb.com/enuff/public_html/Stoves.html
>> For information about CHAMBERS STOVES
>> http://www.ikweb.com/enuff/public_html/Chamber.htm
>

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

From john at gulland.ca Sun Apr 4 13:04:23 1999
From: john at gulland.ca (John Gulland)
Date: Tue Aug 31 21:36:18 2004
Subject: Topic 5. Chimney valves
In-Reply-To: <v01540b03b32d2c4242cf@[204.131.233.37]>
Message-ID: <000101be7ebd$1692f100$21053ad8@JohnGulland>

Ronal wrote about the use of chimney key dampers:

>> 2. John Gulland theory. I believe John Gulland feels that it
is
>> better to control the primary air supply to minimize turbulence within
the
>> chimney. But I never saw any control there either.
>>

The reason was not to minimize chimney turbulence but to promote turbulence
in the combustion chamber. This is what I wrote in my report on the chimney
physics workshop in Honduras:

13. It is better to control air/gas flow through the firebox before the fire
(using a fitted door) than after the fire (using a key damper in the pipe)
because:
* air entering the firebox through small holes and gaps around the door is
more turbulent, which is good for
combustion (if you reduce flow by dampering the chimney, air enters the
firebox lazily)
* chimney pipe dampers restrict flow and draft, even when open
* chimney dampers collect creosote tar and get sticky

The full report is here: http://www.gulland.ca/prowork.htm

I might also point out that any sort of damper downstream of the firebox has
been shown in NA experience to be one cause of indoor air pollution through
errors in their use. That is, users sometimes open the loading door to add
wood without first opening the key damper and the result is smoke roll-out
from the loading door. Where control of the fire is provided upstream of
the fire, this problem is eliminated.

Regards,
John

From english at adan.kingston.net Sun Apr 4 20:52:02 1999
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:36:18 2004
Subject: Forward John Gulland on Efficiency and emissions testing
Message-ID: <199904050049.UAA24989@adan.kingston.net>

------- Forwarded Message Follows -------
From: owner-stoves@crest.org
Date: Sun, 4 Apr 1999 12:39:51 -0400 (EDT)

Stovers,
Thanks to Ron for his reports about his experiences in Nicaragua. The issue
of test methodology is the part of stove development that most interests me.
This is because for twenty years I have watched the evolution of North
American (NA) stove technology and witnessed a transformation that occurred
when a reasonably effective test methodology was agreed upon (actually
mandated by the US Environmental Protection Agency - EPA). Before EPA-style
testing emerged in the mid-to-late 1980s, there were hundreds of stove
manufacturers all making outrageous and unsubstantiated claims for the
special design features that made their product the best, most efficient,
cleanest burning, and so on. After EPA standardised testing, the outrageous
claims disappeared and steady incremental improvements in stove combustion
design began to appear on the market. Now, looking back after more than 10
years of evolution one can easily see how dramatic the changes have been and
how much has been learned. My wish for warm climate cooking stove
technology is the same dramatic transformation that has occurred in NA cold
climate heating stoves. I think the means to achieve it lies constructing a
solid foundation in the form of a reliable test methodology.

I do not, for a moment, suggest that the EPA methodology is right for warm
climate cooker testing -- it is not. However, the knowledge and experience
that underlie it are definitely transferable, and, I would submit, essential
to a successful methodology. For any scientific experiment or test to
useful at all, it must be repeatable, with subsequent test results falling
within a reasonably narrow band. This requirement is most difficult to
achieve with batch-fed woodburning devices because of the irregular form of
the fuel, the more or less random progression of combustion and the absence
of a meaningful steady state combustion. The difficulty in achieving
repeatability from test to test has led NA stove developers and testers to
adopt practices that appear at first to obsessively precise, even fussy.

As an introduction to the methods used in NA, I have produced a web page of
an excerpt from the Wood Energy Technical Training reference manual used in
Canada for the training and certification of wood energy professionals like
retailers, installers, chimney sweeps and inspectors. This excerpt
describes the method mandated by EPA and adapted by a committee of the
Canadian Standards Association (CSA) as standard CSA B415. I warn you: the
text is not scientifically rigorous because the users of the manual needed
only an overview. But it does give you an idea of the equipment and
methodology. Perhaps this introduction will prompt some discussion of how
the underlying knowledge can be adapted.

Here is the link: http://www.gulland.ca/wetteff.htm
And here is the source page that I just put up.
http://www.gulland.ca/stovers.htm
It also has the link to the report of the chimney physics workshop I
delivered in Honduras last December, some of the content of which was
mentioned by Ronal. Please let me know if you find problems loading
anything: I've thrown up and reorganised a fair number of web pages to offer
this and I have done it quickly.

This is all just the beginning of what I hope will be a long and intricate
discussion of stove testing. Hope you find this useful.

Regards,
John
This is for business: http://www.gulland.ca/
This is for pleasure: http://www.wood-heat.com/

From dstill at epud.org Mon Apr 5 00:38:12 1999
From: dstill at epud.org (Dean Still)
Date: Tue Aug 31 21:36:18 2004
Subject: Topic 3. Efficiency measurementss
Message-ID: <01BE7EE4.D0FDF4A0@dialport70.epud.net>

Thanks Ronal for this discussion!

We find that the size of the pot and how full it is very much effect tests. The fuller the pot, the higher the efficiency. Also as the pot gets bigger so rises efficiency.

This can makes tests incomparable.

But, that isn't really important if we just accept it. Until we all use the same pot, filled with the same amount of water, tests from one place cannot be compared to tests done on other places.

Rogerio's tests will accurately give a comparison of the stoves there, which is great and really the important thing..

I was worried by covering the pot, though. Then you end up testing the tightness of the lid more than anything else. By uncovering the pot steam is free to leave equally in all tests. Maybe uncovered pots would be more accurate a test for this reason.

Heat exchange to the pot has the greatest effect on stove fuel efficiency in our tests. A simple skirt (a cylinder) of sheet metal around the pot, leaving a gap of 3/16" will most likely double the stoves efficiency. It's incredible how powerful the skirt can be!

Our tests are the same as Rogerio's:

use two pounds of wood, for example.

Fill the pot 4/5 full. In our pot this means 10 pounds of water. Take start. Temp. of the water

Keep a steady flame during the test

Burn all the wood, keep test going as long as steam rises from the pot.

Figure that the water got to 212F. if it boiled. Figure amount of sensible heat that raised the temperature of the water. Then add the latent heat which is figured at 1,005 BTU per pound of water turned to steam.

We figure that there are 8,600 BTU's per pound of wood. The number doesn't really matter as long as we all use the same one.

We used two pounds of wood so we have theoretically released 17,200 BTU's.

For example, in a test done this week by students, a high mass sand and clay Rocket stove with a skirt, put 4816 BTU's into the pot in a test that took more than an hour. That's 28% efficiency, which is ok for that kind of stove. If you used a larger pot or more water, the efficiency would rise. The highest efficiencies that I've seen were around 40% but that was with expert help and insulated skirts, etc.

I like to use new interns to do tests. They don't yet know how to cheat and make scores higher. (I can cheat on these tests by flooding the pot with flame initially and then cutting back on fuel use, using one or two twigs at a time, just keeping the rolling boil.) Amateur testers helps to get rid of the bias of the experimenter.

Just as an idea, Ronal: at some conference someone should give out the WORLD TESTING POT. If we all agreed on only using one same pot then we could compare %.

Best Regards,

Dean Still
Aprovecho

----------
From: Ronal W. Larson[SMTP:larcon@sni.net]
Sent: Saturday, April 03, 1999 10:17 PM
To: stoves@crest.org
Subject: Topic 3. Efficiency measurementss

I am mainly writing about this to start a dialog on standardization
of tests - and some of this is to see if anyone wants additional data
collected..

I am presuming that they will use standard formulas for calculating
the efficiency and that Rogerio will share those with us as he reports the
results later.

Q2. Should the researchers have asked the regular users of the
stove to do the tests, so as to include this variable in their results?
And Why?

Q3. Should any one stove have several different tests - so as to
average out such variables as wind speed, etc.?

Stovers: Any other questions or comments on things that are really
important to look out for in these efficiency tests? Thanks in advance.

Ron

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

From btremeer at dds.nl Mon Apr 5 11:49:21 1999
From: btremeer at dds.nl (Grant Ballard-Tremeer)
Date: Tue Aug 31 21:36:18 2004
Subject: Kevin's fourth Re: Topic 4. Pollution measurements
In-Reply-To: <v01540b04b32d2c6f4d58@[204.131.233.37]>
Message-ID: <000501be7f7b$d01cb5c0$2f0deed4@blackthorn>

Dear stove testers

There are essentially three different types of emission testing: direct
measurement; indirect measurement; and exposure measurement. I have quoted a
bit of my thesis at the end of this email that describes these methods...
those wanting more details can access the full thesis at
http://www.energy.demon.nl. The best one to use depends on the purpose of
the testing. I believe direct measurements are best for making stove design
improvements (see appendix E of my thesis), indirect methods are best for
establishing baselines for indoor air pollution standards, and exposure
measurements are best for medical studies and intervention assessment (the
full impact of stove, ventilation, behaviour etc.).

I must admit that I can't fully identify which method is being used in
Nicaragua (it sounds like an exposure method), but Kevin Chisholm is
certainly advocating the direct method. What worries me most about the
method Ron has described is that I think the tests will measure kitchen
ventilation conditions and current weather conditions more than the
emissions of the stove! At best it is a type of exposure measurement, but,
unless enough repeated tests are carried out (so as to smooth out the
weather variations) they could be misleading.

Kevin Chisholm wrote:
>In the case of an "open top cooker, that does not normally have a stack, I
>would suggest that one must be made to funnel the off-gases to a consistent
>sample point. In this case, the results could be marginally better than
>actual, in that the suggested "test stack" would marginally help the draft.
>However, the potential error here would be far less significant than a "no
>stack" sample. It would be far less prone to manipulation of the placement
of
>the sample point to get good indicated performance.

I have done extensive measurements of the effect of the test stack. See
http://www.energy.demon.nl/thesis/PhDch3.htm.

A useful background document on emissions called "Lowering Exposure of
Children to Indoor Air Pollution to Prevent Acute Respiratory Infections:
The Need for Information and Action," by Dr. Nigel Bruce is available on the
EHP web site at: http://www.crosslink.net/~ehp/products.htm

I hope this helps in the discussions.
Best wishes
Grant

A quote from my thesis:

"A few studies have been undertaken in an attempt to propose methods of
emission measurement of stoves used by the rural poor. In contrast, many
studies have been carried out on wood-burning stoves used for heating in the
homes of the more affluent (these are occasionally referenced in this thesis
where findings are relevant). The methods can be divided into two broad
categories depending on whether they involve the direct or the indirect
measurement of the pollutants. A third category, receptor or exposure
measurements involve the study of exposure levels experienced by people
within the environment. They are particularly useful in medical studies
where health risks can be accurately assessed. Emission levels measured in
these types of test are complex functions of person, environment, and stove.
a) Direct measurement
Direct measurement of stove emissions involves measurement at the source -
the stove. A hood placed over the stove to capture the emissions is
frequently used. Butcher et al (1984) attempted to design a low cost simple
measurement system for determining simultaneously the emissions and
efficiency of stoves. The method involved the direct measurement of carbon
monoxide and total suspended particulates passing through a hood at a
measured flow rate. Nangale (1992) repeated this work and included an
indicator of hydrocarbon activity by passing the sampling stream through
cold water and measuring the change in acidity of the water.
b) Indirect measurement
Indirect methods measure the influence of the stove on a dilution chamber (a
room simulating a rural dwelling). The emission source strength is
calculated by performing a mass balance for the pollutant in the chamber.
The majority of emission measurement studies relating directly to rural
development focus on indirect measurements using the 'chamber method'"

-------------------
Grant Ballard-Tremeer
btremeer@dds.nl; http://www.energy.demon.nl
-------------------

From btremeer at dds.nl Mon Apr 5 11:49:23 1999
From: btremeer at dds.nl (Grant Ballard-Tremeer)
Date: Tue Aug 31 21:36:18 2004
Subject: Forward John Gulland on Efficiency and emissions testing
In-Reply-To: <199904050049.UAA24989@adan.kingston.net>
Message-ID: <000601be7f7b$d1a66300$2f0deed4@blackthorn>

Thanks John for the background information (nice web page). I fully endorse
the idea of building on the foundations of what has gone before.

>From the point of view of a warm climate cooker a huge amount of work has
been done. Most of it took place before I finished high school - I have on
my shelf a document from 1985 called "Testing the Efficiency of Wood-burning
Cookstoves: International Standards", published by Volunteers in Technical
Assistance, Arlington, Virginia (1985).

I think a major problem is that, although 'standards' were developed so many
years ago there is now no organisation promoting and endorsing the methods
and keeping them up to date. Perhaps after some discussion on the 'stoves'
list, the 1985 standards can be updated? We can also put some thought into
the right organisation to endorse them and keep them 'living'...

By the way, VITA publications are obtainable from Volunteers in Technical
Assistance, 1815 North Lynn Street, Suite 200, Arlington, Virginia
22209-2079, USA. I can't remember how expensive it is and I'm not sure
whether copies are still available: - I'll contact them and see - if not
I'll see if I can somehow get it onto the HEDON web page and let you know.

Other useful reading is S. Baldwin, Biomass Stoves: Engineering Design,
Development & Dissemination, Volunteers in Technical Assistance, Arlington,
Virginia (1987); and B. Stewart, Improved Wood, Waste and Charcoal Burning
Stoves ? A Practitioners' Manual, Intermediate Technology Publications,
London (1987).

All the best
Grant

-------------------
Grant Ballard-Tremeer
btremeer@dds.nl; http://www.energy.demon.nl
-------------------

-----Original Message-----
From: owner-stoves@crest.org [mailto:owner-stoves@crest.org] On Behalf Of
*.English
Sent: 05 April 1999 03:53
To: stoves@crest.org
Subject: Forward John Gulland on Efficiency and emissions testing

------- Forwarded Message Follows -------
From: owner-stoves@crest.org
Date: Sun, 4 Apr 1999 12:39:51 -0400 (EDT)

This is all just the beginning of what I hope will be a long and intricate
discussion of stove testing. Hope you find this useful.

Regards,
John
This is for business: http://www.gulland.ca/
This is for pleasure: http://www.wood-heat.com/

From btremeer at dds.nl Mon Apr 5 11:49:27 1999
From: btremeer at dds.nl (Grant Ballard-Tremeer)
Date: Tue Aug 31 21:36:18 2004
Subject: Dean Still on Topic 3. Efficiency measurements
In-Reply-To: <01BE7EE4.D0FDF4A0@dialport70.epud.net>
Message-ID: <000701be7f7b$d3393800$2f0deed4@blackthorn>

I partly agree with Dean Still about the pot lid question if evaporated
water is used as the indicator of energy entering the pot. However
evaporation is (usually) not the real aim of cooking and we are in danger of
developing stoves that evaporate water efficiently... does this imply that
they cook efficiently I wonder?

I have a problem with the method of 'taking a given amount of fuel and
burning it virtually to completion' that is used in Dean and Rogerio's
tests. It means that we will gradually develop stoves that burn 'two pounds'
(or whatever quantity) of wood efficiently. Different stoves have different
optimum loading levels (and optimum fuel size incidentally). I think that
Dean's finding that efficiency increases when the pot is fuller is one of
the results of this and shows a flaw in this method - as water quantity is
increased the ratio of 'heating up' to 'vigorous boiling' to 'simmering'
changes substantially - essentially the required 'task' changes between
tests. In tests I have done (where an optimal amount for each stove was used
to complete the task - heat to boiling and simmer for 30 minutes as
specified in the 1985 VITA standards) no statistically significant effect of
the quantity of water could be detected. This is as I would expect - all
other things being equal, the water is merely measurement meter for energy
delivered to the pot. My test results can be found at
http://www.energy.demon.nl/thesis/PhDch4.htm. Incidentally the VITA
standards recommend filling pots to 2/3s

Enough for now... a closing thought: I think we should answer carefully 'why
am I testing?' Surely our efficiency measure should be "Fuel used per task"
(or energy per a local standard meal) since in the long run that is what we
are aiming to improve! Perhaps we should have a standard stove which we can
each test in a way that most conforms to local usage conditions and needs.
The we could say: my new stove is 1.5 times better than the standard stove
for 'such-and-such task'. I have a problem with a standard pot... if the pot
is important, all the more reason to use the same pot that the end user will
use.

Three cheers for what Dean wrote here: "Rogerio's tests will accurately give
a comparison of the stoves there, which is great and really the important
thing..". Yes! This means local pots, wood loading, fire tending, etc. etc.

Ok - I have to stop for now... I look forward to the ensuing debate.
Best wishes
Grant

PS. Here's a relevant quote from the intro of chapter 4 of my thesis:
"All emission studies reported in the literature have been conducted using
lids on pots but efficiency studies are usually conducted without pot lids.

The use of pot lids in efficiency measurements has been the subject of
considerable debate. Initially the VITA standards recommended the use of
lids (December 1982 first edition). It is recommended that lids are not used
in the revised edition (VITA 1985). The reasons (suggested by Baldwin
1987:262,263) are that "lids proved to be cumbersome in practice and
additionally did not reduce the scatter in the data but rather increased
it."
The amount of water evaporated when pot lids are used is partially dependent
on how well lids fit, and partially dependent on the fire power. If the
water temperature during the simmering phase is below boiling very little
water vapour will escape, but if the water boils the lid will be pushed
open. The Specific Fuel Consumed (SFC), the 'standard' measure of
efficiency, which is defined as fuel used during a test divided by the mass
of water evaporated (VITA 1985:7) is extremely sensitive to the use of lids.
The VITA standards, however, erroneously allow the use of lids "if they are
needed to reduce the effect of drafts on evaporation rate" (1985:4).
Baldwin points out that "by not using a lid, evaporation rates are higher
and the stove must be run at a somewhat higher power to maintain the
temperature than is the case with a lid." (1987:263). This means that
without a lid low power is not really achieved during the simmering phase."
//Grant

-------------------
Grant Ballard-Tremeer
btremeer@dds.nl; http://www.energy.demon.nl
-------------------

-----Original Message-----
From: owner-stoves@crest.org [mailto:owner-stoves@crest.org] On Behalf Of
Dean Still
Sent: 04 April 1999 21:33
To: 'stoves@crest.org'
Subject: RE: Topic 3. Efficiency measurementss

Thanks Ronal for this discussion!

We find that the size of the pot and how full it is very much effect tests.
The fuller the pot, the higher the efficiency. Also as the pot gets bigger
so rises efficiency.

This can makes tests incomparable.

But, that isn't really important if we just accept it. Until we all use the
same pot, filled with the same amount of water, tests from one place cannot
be compared to tests done on other places.

Rogerio's tests will accurately give a comparison of the stoves there, which
is great and really the important thing..

I was worried by covering the pot, though. Then you end up testing the
tightness of the lid more than anything else. By uncovering the pot steam is
free to leave equally in all tests. Maybe uncovered pots would be more
accurate a test for this reason.

Heat exchange to the pot has the greatest effect on stove fuel efficiency in
our tests. A simple skirt (a cylinder) of sheet metal around the pot,
leaving a gap of 3/16" will most likely double the stoves efficiency. It's
incredible how powerful the skirt can be!

Our tests are the same as Rogerio's:

use two pounds of wood, for example.

Fill the pot 4/5 full. In our pot this means 10 pounds of water. Take start.
Temp. of the water

Keep a steady flame during the test

Burn all the wood, keep test going as long as steam rises from the pot.

Figure that the water got to 212F. if it boiled. Figure amount of sensible
heat that raised the temperature of the water. Then add the latent heat
which is figured at 1,005 BTU per pound of water turned to steam.

We figure that there are 8,600 BTU's per pound of wood. The number doesn't
really matter as long as we all use the same one.

We used two pounds of wood so we have theoretically released 17,200 BTU's.

For example, in a test done this week by students, a high mass sand and clay
Rocket stove with a skirt, put 4816 BTU's into the pot in a test that took
more than an hour. That's 28% efficiency, which is ok for that kind of
stove. If you used a larger pot or more water, the efficiency would rise.
The highest efficiencies that I've seen were around 40% but that was with
expert help and insulated skirts, etc.

I like to use new interns to do tests. They don't yet know how to cheat and
make scores higher. (I can cheat on these tests by flooding the pot with
flame initially and then cutting back on fuel use, using one or two twigs at
a time, just keeping the rolling boil.) Amateur testers helps to get rid of
the bias of the experimenter.

Just as an idea, Ronal: at some conference someone should give out the WORLD
TESTING POT. If we all agreed on only using one same pot then we could
compare %.

Best Regards,

Dean Still
Aprovecho

From english at adan.kingston.net Mon Apr 5 17:19:49 1999
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:36:18 2004
Subject: (Fwd) Peter Young on Topic 9. Hoods
Message-ID: <199904052116.RAA27891@adan.kingston.net>

Check out past issues of Boiling Point accessible on
http://payson.tulane.edu:8888/

1 Chimneys & Hoods for smoke removal. M E Crowther Coal Research
Establishment, Boiling Point No 28 August 1992

2 A breath of Fresh Air for Smoky Houses. Pete Young. ITDG Boiling Point
No 34 September 1994.

Pete Young

From karve at wmi.co.in Tue Apr 6 06:37:12 1999
From: karve at wmi.co.in (karve)
Date: Tue Aug 31 21:36:18 2004
Subject: Efficiency testing in India
Message-ID: <3709E490.EA9D9852@wmi.co.in>

Dear stovers,
A lot is being said about efficiency testing in warm climates, so I
would like to give a brief description of what is happening here in
India.
In India, all the Technical Back up support Units (TBUs) established
in different parts of the country under the umbrella of the Ministry of
Nonconventional Energy Sources (MNES) develop improved stove models for
their respective regions. MNES has recommended a particular efficiency
test and any new stove is deemed to be an 'improved' model if it gives
an efficiency above 20% by this test (the traditional stoves have
efficiencies in the range of 10-20% by this test).
Originally the recommended test was the Boiling and Evaporation
Efficiency (BEE) test. However, the result of this test is heavily
dependent on the rate of water evaporation which in turn depends on a
lot of extraneous factors which are time as well as location specific.
Therefore a new test has been recommended which is called the Thermal
Efficiency (TE) test.
Following is a brief description of the test.

1. The solid fuel should be free of moisture and its calorific value is
to be determined using the Bomb calorimeter.
2. Determine the burning capacity of the stove, i.e. the rate of fuel
consumption/hour. Take the fuel required for one hour and divide it into
four equal lots.
3. Take two identical aluminium vessels with lids and stirrers. The size
of the vessels is determined by the stove size and each vessel is to be
filled with water at room temperature to 2/3 of its capacity.
4. Stack the first lot of the fuel in the combustion chamber. Sprinkle a
measured quantity of kerosene over it and start the fire. Simaltaneously
start the stopwatch. Feeding of fresh fuel lot should be done every 15
minutes.
5. Put one vessel on the stove the moment the fire is started. Allow the
water to rise to 80 deg.C and then stirr it while allowing the
temperature to rise upto 5 deg.C below the local boiling point.
6. Remove the vessel from the stove and put the second one on the fire
and repeat the procedure.
7. Empty the first vessel, refill it with fresh water at room
temperature and keep it ready to replace the second one, when the
desired temperature is reached in the second vessel, and so on.
8. Energy input = [Calorific value of the fuel (kcal/kg) x Mass of solid
fuel (kg)] + [Calorific value of kerosene (kcal/kg) x Mass of kerosene
(kg)]
Energy output = {[0.214 x Mass of vessel complete with lid and stirrer
(kg)] + [1x Mass of water in a vessel (kg)]}x{(No. of vessel runs
-1)x[Final temperature of water (deg.C) - Initial temperature of water
(deg. C)] + [Final temperature of water in the last vessel run(deg. C) -
Initial temperature of water (deg.C)]}
where O.214 is specific heat of aluminium in kcal/kg deg. C and that
of water is 1 kcal/kg deg. C.

An important drawback of both the BEE as well as the TE tests is
that they assume that it is possible to add fuel to the stove during
operation. This is not always the case. I realised this problem about 5
years ago when I was working on a biomass burning stove. In this stove
the biomass is packed in the stove body in a specific geometry and once
the fire is started, there is no scope for adding any more fuel. I call
such stoves 'nonreplenishable stoves'. In these stoves, the variation of
energy input and output with time also becomes an important parameter in
addition to the average efficiency. I therefore suggested that for
nonreplenishable stoves, the TE test should be conducted while keeping
the stove on a weighing scale and at each change of the vessel on the
stove, the time and the mass of the stove be logged. The energy input
and energy output over the time interval of each vessel-run can thus be
calculated.
Although I later came to know that this was by no means a new idea,
apparently it was new for the Indian stove scientists at that time!
The paper based on this modification of TE test generated a lot of
interest when it was presented in a workshop and even now people working
on nonreplenishable stoves are citing it in their publications. In my
work too I found that this simple modification gives a lot of insight
into the time evolution of the combustion as well as heat transfer
processes in the stove operation and helps a great deal in design
improvement. So perhaps, under laboratory conditions it may be fruitful
to test even the replenishable stoves in the same manner, i.e., fill the
fuel chamber to the capacity and conduct the modified TE test only till
the fuel lasts. Of course it is easier to do for the portable metallic
stoves
than for the fixed mud stoves.
In any case, whatever may be the efficiency under laboratory
conditions, rigourous testing under actual cooking conditions is a must.
For this purpose, in India, a TBU adopts a few villages in its region of
operation and the new stove models are first tried out in these villages
for an year or two. It's only after a positive response is received from
the test users regarding the efficiency, cleanliness as well as ease of
operation, that the stove can be recommended to MNES for inclusion in
the National Programme on Improved stoves.
I would certainly like to receive your suggestions/comments on the
TE test.
With regards,
Priyadarshini Karve.

From woodcoal at mailbox.alkor.ru Tue Apr 6 09:32:24 1999
From: woodcoal at mailbox.alkor.ru (Woodcoal)
Date: Tue Aug 31 21:36:18 2004
Subject: Volcanic material
Message-ID: <01be802f$32938720$LocalHost@22>

<snip> (Topic 8.
Volcanic material)

4. Use in stoves. I think the volcanic material has greatpotential in
stoves. But maybe I am wrong. Has any list member any moredata
to report? The thermal resistance characteristics? The
lifetimeunder elevated temperatures?Ron
This material use for construction of furnaces in Armenia.There are many
mountains and a lot of this material. Armenians name it "tuf".
Yury

From VHarris001 at aol.com Tue Apr 6 21:39:49 1999
From: VHarris001 at aol.com (VHarris001@aol.com)
Date: Tue Aug 31 21:36:18 2004
Subject: Conversion Buddy Freeware
Message-ID: <7a9bc52.243c10a2@aol.com>

Dear Gasification Group & Stovers,

If you are like me, constantly struggling with conversions from metric to US
measurements and back again, you should check out this web site. Conversion
Buddy is a freeware (free) conversion program with about 1700 factors, and is
customizable. Also available - Expression Buddy, which interprets
expressions containing up to 51 variables.

http://users.ntr.net/~jpresley/

For other conversion programs and info available, check out:

http://chemengineer.miningco.com/library/weekly/aa041398.htm?terms=standard&CO
B=home

Vernon Harris
VHarris001@aol.com
Stoves List SPONSORS and ARCHIVES:
http://solstice.crest.org/renewables/stoves-list-archive/
Stoves Webpage
http://www.ikweb.com/enuff/public_html/Stoves.html
For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From rmiranda at sdnnic.org.ni Wed Apr 7 01:11:56 1999
From: rmiranda at sdnnic.org.ni (Rogerio Miranda)
Date: Tue Aug 31 21:36:18 2004
Subject: Efficiency testing in India
Message-ID: <3.0.5.32.19990406224333.007c5cb0@pop.sdnnic.org.ni.>

Dear Priyadarshini Karve:

How can we get more information about the National Programme on Improved
stoves in India ?

We are about to design a strategy for stove development for Nicaragua, and
would be very interesting to look at the main components of the national
programme of India.

thanks

rogerio
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Rogerio Carneiro de Miranda
Coordinador Proyecto EMOLEP
CATIE - PROLEÑA
Apartado Postal C-321
Managua, Nicaragua
TELEFAX (505) 276 2015, 270 5448
EMAIL: rmiranda@sdnnic.org.ni
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Stoves List SPONSORS and ARCHIVES:
http://solstice.crest.org/renewables/stoves-list-archive/
Stoves Webpage
http://www.ikweb.com/enuff/public_html/Stoves.html
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http://www.ikweb.com/enuff/public_html/Chamber.htm

From ensol at actrix.gen.nz Thu Apr 8 18:52:08 1999
From: ensol at actrix.gen.nz (Shelley Hood, Rob Bishop)
Date: Tue Aug 31 21:36:18 2004
Subject: Coal burning emissions
Message-ID: <370D333B.DF3@actrix.gen.nz>

Hi folks, I've been lurking for several months, watching the discussions
and looking for anything relating to my particular interest, more
efficient residential heating.

Here in New Zealand there's a controversy about domestic coal use in the
highly polluted city of Christchurch. They're talking about banning coal
burning for home heating (lots of it in open fireplaces).

I have two related questions that you may be able to help with:

1) Why does coal seem to be so dirty to burn in a home stove? Is it
because coal stoves are normally filled up with coal, then the heat
output controlled by varying combustion air (as opposed to a wood stove,
where you can also vary the fuel load)? Or is it due to the ash content
of coal, or sulfur, or something else?

2) Do you know of any references about how much emissions are actually
produced by a residential coal burning heater?

The Canterbury Regional Council have estimated that a residential coal
stove emits 22 g/kg of PM-10, compared to a wood stove of 10 g/kg. EPA's
AP-42 database of emissions only looks at industrial coal burning.

To me, it looks like wood and coal are not that different: both mixes of
carbon, volatiles, moisture and ash. Hearth.net says (on the
coaltips.html page) “Coal does not produce creosote, so chimney fires
are not a concern. It does, however, produce a fly ash which can clog
elbows or heat exchangers.”

Why no creosote? Are there different volatiles in coal? Does this mean
most coal stove emissions are ash, instead of condensed volatiles?

Thank you in advance for your help in "clearing the air" down here.
--
Cheers

Rob Bishop
Energy Solutions Ltd.
P.O. Box 12-558
Welington, New Zealand
ph/fax +64-4-233-8533
Stoves List SPONSORS and ARCHIVES:
http://solstice.crest.org/renewables/stoves-list-archive/
Stoves Webpage
http://www.ikweb.com/enuff/public_html/Stoves.html
For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From shayden at NRCan.gc.ca Fri Apr 9 10:07:22 1999
From: shayden at NRCan.gc.ca (Hayden, Skip)
Date: Tue Aug 31 21:36:18 2004
Subject: Coal burning emissions
Message-ID: <31EC3D073B34D111BC6000805FBE3A8A69C842@S0-BCC-X1>

The reasons that coal burns much dirtier than wood is meriad, but has little
to do with varying the fuel load. While the volatility of most woods are
very similar, volatility of coals vary dramatically. Ash content does have
a role, as much as anything else in muffling the combustion. Coal ash
content can vary from a very low 2% to as high as 40%, while wood tends to
be in the 1% range. Equilibrium moisture contents for coals also vary from
perhaps 1% for an anthracite or semi-anthracite, to over 35% for lignites.
Handling the latent heat and the effect it has on combustion is important.

Emissions from coal stoves also tend to have much more carbon (soot-type)
than do wood-fired units, along with a lot of fly ash.

Furthermore, components of coal tend to have an aromatic structure, so that
the probability of high PAH emissions is serious.

Having said all this, there was a lot of work in England 15-20 years ago to
develop smokeless coal stoves, where advanced combustion design using a
sidedraft-into-refractory was combined with a fuel which had been "cleaned"
and possessed quite specific properties. A design developed by the British
Coal Board looked especially promising, but I am unsure where that sits
today.

Having said this, I would tend to side with the NZ authorities being quite
severe on coal stoves, unless they were of a dramatically advanced design,
developed specifically for coal, and that the coal supplied also had to be
in a very specific range of properties.

Skip Hayden

A.C.S. Hayden
Senior Research Scientist
Advanced Combustion Technologies, ETB/CETC
1 Haanel Drive
Ottawa, Canada K1A 1M1

Tel: (613) 996-3186
Fax: (613) 992-9335
e-mail: skip.hayden@nrcan.gc.ca

> ----------
> From: Shelley Hood, Rob Bishop[SMTP:ensol@actrix.gen.nz]
> Sent: Thursday, April 08, 1999 6:52 PM
> To: stoves@crest.org
> Subject: Coal burning emissions
>
> Hi folks, I've been lurking for several months, watching the discussions
> and looking for anything relating to my particular interest, more
> efficient residential heating.
>
> Here in New Zealand there's a controversy about domestic coal use in the
> highly polluted city of Christchurch. They're talking about banning coal
> burning for home heating (lots of it in open fireplaces).
>
> I have two related questions that you may be able to help with:
>
> 1) Why does coal seem to be so dirty to burn in a home stove? Is it
> because coal stoves are normally filled up with coal, then the heat
> output controlled by varying combustion air (as opposed to a wood stove,
> where you can also vary the fuel load)? Or is it due to the ash content
> of coal, or sulfur, or something else?
>
> 2) Do you know of any references about how much emissions are actually
> produced by a residential coal burning heater?
>
> The Canterbury Regional Council have estimated that a residential coal
> stove emits 22 g/kg of PM-10, compared to a wood stove of 10 g/kg. EPA's
> AP-42 database of emissions only looks at industrial coal burning.
>
> To me, it looks like wood and coal are not that different: both mixes of
> carbon, volatiles, moisture and ash. Hearth.net says (on the
> coaltips.html page) "Coal does not produce creosote, so chimney fires
> are not a concern. It does, however, produce a fly ash which can clog
> elbows or heat exchangers."
>
> Why no creosote? Are there different volatiles in coal? Does this mean
> most coal stove emissions are ash, instead of condensed volatiles?
>
> Thank you in advance for your help in "clearing the air" down here.
> --
> Cheers
>
> Rob Bishop
> Energy Solutions Ltd.
> P.O. Box 12-558
> Welington, New Zealand
> ph/fax +64-4-233-8533
> Stoves List SPONSORS and ARCHIVES:
> http://solstice.crest.org/renewables/stoves-list-archive/
> Stoves Webpage
> http://www.ikweb.com/enuff/public_html/Stoves.html
> For information about CHAMBERS STOVES
> http://www.ikweb.com/enuff/public_html/Chamber.htm
>
Stoves List SPONSORS and ARCHIVES:
http://solstice.crest.org/renewables/stoves-list-archive/
Stoves Webpage
http://www.ikweb.com/enuff/public_html/Stoves.html
For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From MIHWP at TTACS.TTU.EDU Mon Apr 12 19:41:29 1999
From: MIHWP at TTACS.TTU.EDU (Harry W. Parker)
Date: Tue Aug 31 21:36:18 2004
Subject: Gasification-A Bridge to the Coming Sustainable World
In-Reply-To: <d7a424c4.24434da5@cs.com>
Message-ID: <3712661E.3B9279F5@ttacs.ttu.edu>

Hello Tom and all,

Gasification is the bridge between two worlds as observed by Tom..

Gasification is also a common ground for fossil fuel (coal) and
biofuels to meet since the intermediate product is always CO and H2.
>From this synthesis gas all "petrochemicals" and fuels are possible!!

Gasification of coal is already commercial in the US. The Tenn Eastman
Plant in Knoxville Tenn. It was build and then expanded. This facility
is a large scale operation! Does biomass gasification compete??

I will be very pleased to work with firms who desire to make biomass
gasification compete as per the RFP that has been posted to this same
group from SERI.

Harry

<><><><><><><><><><><><><><><><><><><><><><><><><><><>

Harry W. Parker, Ph.D., P.E.

Professor of Chemical Engineering Consulting Chemical Engineer
Texas Tech University 8606 Vicksburg Avenue
Lubbock, TX 79409-3121 Lubbock, TX 79424
<><><><><><><><><><><><><><><><><><><><><><><><><><><>

From english at adan.kingston.net Mon Apr 12 21:48:07 1999
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:36:18 2004
Subject: (Fwd) BOUNCE stoves@crest.org: Non-member submission from [
Message-ID: <199904130145.VAA04361@adan.kingston.net>

------- Forwarded Message Follows -------
From: owner-stoves@crest.org
Date: Sun, 11 Apr 1999 12:07:22 -0400 (EDT)
To: owner-stoves@crest.org
Subject: BOUNCE stoves@crest.org: Non-member submission from [Reedtb2@cs.com]

>From stoves-owner@crest.org Sun Apr 11 12:07:21 1999
Received: from csimo01.mx.cs.com (csimo01.mx.cs.com [198.81.17.74])
by solstice.crest.org (8.8.7/8.8.7) with ESMTP id MAA06981;
Sun, 11 Apr 1999 12:07:20 -0400 (EDT)
From: Reedtb2@cs.com
Received: from Reedtb2@cs.com
by csimo01.mx.cs.com (IMOv20.9) id 6VJWa24127;
Sun, 11 Apr 1999 12:06:46 -0400 (EDT)
Message-ID: <e2967c3e.24422296@cs.com>
Date: Sun, 11 Apr 1999 12:06:46 EDT
Subject: SURFACE COMBUSTION BURNERS
To: gasification@crest.org, stoves@crest.org
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
X-Mailer: CompuServe 2000 32-bit sub 20
Reply-To: Reedtb2@cs.com

Dear Skip:

Surface combustion burners are all the rage today, and I am sure you are
talking about the same effect in your boiler radiation (below).

Usually SCBs have the fuel passing through from the rear and burning within
the outer surface. You see them in outdoor restaurants in mild climates
hotting up the customers with radiant heating. I bought one for about $100
to heat my lab using propane. It is amazing that one feels the heat 5-10
feet away, but no heat if you can't see the surface. Radiation in general
penetrates smoke and gases to carry heat to solid surfaces (like you and me).

Shell makes a special (expensive) alloy called FECRALLOY (FE, iron, CR,
chromium) that is particularly good for this if you need the ultimate in
lifetime and temperature, but stainless and particularly kanthal will be good
too.

Good topic that we all need to know more about, both for efficient radiant
heating and for reducing CO.

TOM REED

While using my large boilers with the 5'x5' firebox, that has the duraboard
and cerablanket refractory, it seems easier to get a bright red glow from the
expanded metal that protects it.
I am now thoroughly convinced that what is happening is a catalytic reaction
from the carbon monoxide caught between the expanded metal and the surface of
the duraboard.
I quantify this by stating:
A 'cool' wood fire that is 2-3' away is obviously not hot enough to get the
metal that hot.
There is a large concentration of CO falling down from the top of the chamber
uniting with oxygen, all this on the surface of the walls.
The action is most vigorous where the surface is even coarser (cerablanket
vs.
duraboard).
The radiation is so intense that it smokes the handle of a shovel immediately

even outside the fire door or about 4 feet from the actual fire. these are
some long rays!
In boilers with brick type refractory, this action is not even noticable.
Same with the radiation.

Conclusion: CO combustion extends very long ray type radiation
There is definite catalytic reaction occuring on the surfaces between
the
ceramic hairs and expanded metal.

Temperatures of up to 2000 degrees (F) are easily obtained by CO and
other
waste gases from simple catalytic reaction. This process also is yielding a
positive delta H heat value.

Now, I would submit to all on this board that making electricity is
an
expensive rabbit to chase. The idea is to show a profit with this so called
bio-gas, gassification, or whatever silly educated name you want to put on
what us boiler folks have always called 'combustion'.
It seems to me that a bright future is available by taking this
cellulose and
allowing it to combust in a chamber with extensive ceramic fibers covered
with
stainless steel perhaps even a coating of platinum ($?) and achieving temps
of
2500 degrees quite easily and cleanly. Aside from the oxidation of the
nitrogen, and it's resulting pollution, these temperatures are ideal for
SMELTING of basic non-ferrous metals and perhaps even the refining of such?
The profit from this type of operation obviously is greater than
creating
methanes, electricity or other currently used modus operendi. If nothing
else, start up capital is dramatically less.

As an aside, I can tell you that these type of furnaces make one
hell of a
clean burning dry bottom boiler! Mr. Zebly is familiar with my 120' boilers
and I'll bet he is amazed that I get steam in 20 minutes from start up time
and full power in 30 minutes. (that's approx. 100 gals water and 1200 lbs of
steel going from 50 degrees to 330 degrees.) you do the math....

Wadda ya tink, guys?

Skip Goebel
Sensible Steam
Branson, MO
www.sensiblesteam.com

From english at adan.kingston.net Mon Apr 12 22:33:07 1999
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:36:18 2004
Subject: (Fwd) BOUNCE stoves@crest.org: Non-member submission from [
Message-ID: <199904130230.WAA10654@adan.kingston.net>

Dear Skip:

Surface combustion burners are all the rage today, and I am sure you are
talking about the same effect in your boiler radiation (below).

Good topic that we all need to know more about, both for efficient radiant
heating and for reducing CO.

TOM REED

Conclusion: CO combustion extends very long ray type radiation
There is definite catalytic reaction occuring on the surfaces between
the
ceramic hairs and expanded metal.

Temperatures of up to 2000 degrees (F) are easily obtained by CO and
other
waste gases from simple catalytic reaction. This process also is yielding a
positive delta H heat value.

Wadda ya tink, guys?

Skip Goebel
Sensible Steam
Branson, MO
www.sensiblesteam.com

From english at adan.kingston.net Tue Apr 13 07:25:17 1999
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:36:18 2004
Subject: (Fwd) Tom Reed respondes to Skip Goebel
Message-ID: <199904131122.HAA10493@adan.kingston.net>

Dear Skip:

Surface combustion burners are all the rage today, and I am sure you are
talking about the same effect in your boiler radiation (below).

Good topic that we all need to know more about, both for efficient radiant
heating and for reducing CO.

TOM REED

Conclusion: CO combustion extends very long ray type radiation
There is definite catalytic reaction occuring on the surfaces between
the
ceramic hairs and expanded metal.

Temperatures of up to 2000 degrees (F) are easily obtained by CO and
other
waste gases from simple catalytic reaction. This process also is yielding a
positive delta H heat value.

Wadda ya tink, guys?

Skip Goebel
Sensible Steam
Branson, MO
www.sensiblesteam.com

From english at adan.kingston.net Wed Apr 14 07:07:02 1999
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:36:18 2004
Subject: (Fwd) Dan Cambell, Annotated Bibliography on Acute Respiratory
Message-ID: <199904141104.HAA18536@adan.kingston.net>

The "Annotated Bibliography on Acute Respirtatory Infections and Indoor Air
Pollution," by D. Kammen, G. Wahhaj, and M.Y. Yiadom is now available via
the EHP web site at:

http://www.crosslink.net/~ehp/aribib2.htm

We are addiing links from the subject terms to the author index to make the
bibliography more user-friendly but it will require a couple of days to
complete this.

Below is an introduction to the bibliography.

BROAD-SEARCH ANNOTATED BIBLIOGRAPHY ON Acute Respiratory Infections (ARI)
and Indoor Air Pollution (With Emphasis on Children Under Five in Developing
Countries)

Prepared by Daniel M. Kammen; Gemini Wahhaj; Maame Yaa Yiadom

December 1998; Under EHP Activity No. 263-CC

INTRODUCTION TO THE BROAD-SEARCH ANNOTATED BIBLIOGRAPHY

In July 1997, the second International Conference on Acute Respiratory
Infections was held in Canberra, Australia

(http://nceph.anu.edu.au/user/rnd868/aricon.html#THE), thirteen years after
the first in 1984 (Douglas & Kerby-Eaton, 1985). Although the first
conferenceincluded papers on environmental risk factors for Acute
Respiratory Infection (ARI), in the second there was not one paper or
plenary
presentation on these factors in developing countries, and only one session
out of 34 on
the topic in developed countries. This is partly due to a perception in the
ARI professional community that little progress has been made in
understanding this complicated set of issues. Wishing to dispel this image,
although
recognizing that there is still much room for additional work, EHP prepared
a bibliography of material related to air pollution and childhood ARI in
developing countries, the vast bulk of which had been published in the
period between the two conferences.

The first (McCracken and Smith, 1997) and second (Kammen, Wahhaj, and
Yiadom, 1998) ARI bibliographies are complementary. References are not
repeated in
the two editions; users of these resources should search both bibliographies
for=
references and abstracts for the widest and most update search of papers on
acute respiratory illness.

That bibliography, compiled by John P. McCracken and Kirk R. Smith and
published in 1997, contains 192 references pertaining to air pollution as a
risk factor for acute respiratory infections (ARI). Its focus is ARI in
young children in developing countries, who bear the greatest burden of
ill-health=
from ARI worldwide and many of whom seem to have high exposures to a number
of harmful air pollutants. A major purpose of the bibliography was to
provide
an easily accessed source of information on the relationship between ARI and
air pollution to researchers and field staff in developing countries, where
access to current publications may be limited. For this reason, abstracts
were
included whenever available. The references, which dated from 1968 to 1997,
were collected from several databases including Medline, Cambridge

Abstracts, and the library database of the Environmental Health Project
(EHP/USAID).
Also included were reports, conference summaries, and other unpublished
works
from the authors collection at the University of California.

This new annotated bibliography contains citations and abstracts for 235
papers that relate to air pollution and environmental exposure as a risk
for=
acute respiratory infection (ARI). As did the predecessor volume, this
bibliography focuses on children and environmental health conditions in
developing nations.

This bibliography augments the 1997 Annotated Bibliography on Acute
Respiratory Infections (ARI) and Indoor Air Pollution. This 1998 edition
follows the same general format as its predecessor, with the addition of
several new subject categories to reflect a wider search on the ARI
exposure, dose, disease, and outcome(s) literature. The geographic
categories
have
been expanded as well to reflect some of the areas where a significant
number
of
studies were conducted.

As in the 1997 bibliography, four principal criteria have been applied to
choose references:

Children under 5 years
Developing countries
Indoor air pollution
Confirmed Acute Lower Respiratory Infection or pneumonia

All references generally meeting at least three of these criteria were
included in the 1997 edition, while references meeting two of these criteria

were included in this current (1998) edition. This less restrictive search
is the genesis of the title, =11broad search=12 bibliography.

The references in this bibliography, which date from 1968 to 1998, have
been=
collected from several databases, including Lexus-Nexus, Medline, Cambridge
Abstracts, university-supported search engines at Princeton University, the
California Institute of Technology and the University of California , and
the library database of the Environmental Health Project (EHP/USAID).

From Alex.English at adan.kingston.net Wed Apr 14 22:46:51 1999
From: Alex.English at adan.kingston.net (*.english)
Date: Tue Aug 31 21:36:18 2004
Subject: Pictures of Producer Gas Storage, Dale Costich
Message-ID: <199904150243.WAA01654@adan.kingston.net>

There has been a discussion on the Gasification List about storing
producer gas in an Ag Bag. Dale has used it for cooking among other
things. Some pictures of his set up can be viewed on the Stoves
Webpage. At http://www.ikweb.com/enuff/public_html/Stoves.html
The link is under the NEW section. Or link directly to
http://www.ikweb.com/enuff/public_html/Gasbag/Gasbag.htm

Alex
Alex English
RR 2 Odessa, Ontario, Canada
K0H2H0 613-386-1927
Fax 613-386-1211
Stoves List SPONSORS and ARCHIVES:
http://solstice.crest.org/renewables/stoves-list-archive/
Stoves Webpage
http://www.ikweb.com/enuff/public_html/Stoves.html
For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From Reedtb2 at cs.com Sat Apr 17 18:25:28 1999
From: Reedtb2 at cs.com (Reedtb2@cs.com)
Date: Tue Aug 31 21:36:18 2004
Subject: Onsite gas storage
Message-ID: <afbfac19.244a6449@cs.com>

Dear Peter Davies and all Responders:

I (and Community Power and the Biomass Energy Foundation) appreciate all the
great comments and suggestions for gas storage that have appeared this week.

I have been very actively building gasifiers and stoves and generators this
last year with BEF and CPC. Last week I suggested to my wife, Vivian, that
we buy or build an alternate energy cabin close to our home in Colorado,
probably in the mountains and close to our home in Golden, and not requiring
a so called Sport Utility Vehicle, (SUV = Silly, Ugly Vanity) to access.

Gas is capable of supplying all my needs, as witness any Motorhome or house
trailer operating with propane.

I plan to install a 1 day gas storage unit that I would fill daily from a
small gasifier before breakfast. It would then run cooking, mantle lamps, a
micro generator for communication and a gas refrigerator.

Gasification of 1 kg of biomass will generate 2.5 m3 of gas or 1 kWh of power
or 5 kWh of heat. How much energy will I need for the good life in the
woods?

~~~~~~

I have been storing up all these comments on gas storage and web pages on gas
storage in my email directory. Isn't it marvellous that the whole world has
become a connected community of ideas. After all, behind every detail of our
current civilization lies plans, testing etc.

It crossed my mind that we could even have a world conference on GAS STORAGE.
We might get a budget of $100K from NREL or DOE. Lots of people would like
to travel to Colorado to yak about the commercial and environmental and
efficiency aspects of gas energy storage.

But then, by Email we have already had that conference. Keep the ideas
flowing,....

TOM REED
Stoves List SPONSORS and ARCHIVES:
http://solstice.crest.org/renewables/stoves-list-archive/
Stoves Webpage
http://www.ikweb.com/enuff/public_html/Stoves.html
For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From eta-pet at eta-team.com Sun Apr 18 15:03:28 1999
From: eta-pet at eta-team.com (Albrecht Kaupp)
Date: Tue Aug 31 21:36:18 2004
Subject: Onsite gas storage
In-Reply-To: <afbfac19.244a6449@cs.com>
Message-ID: <199904181903.PAA01648@solstice.crest.org>

Tom, you have a point here. Looking at the major bottle neck of
commercalisation
of small scale gasification- the difficulties to keep the process continously
going due to little control over the fuel quality- the best would be gas
storage
(for small consumption only). A recent pretty frank discussion about the
ongoing
commercialisation of process heat gasifiers for the silk industry in India
showed
the usual difficulties that have been well known over the last 60 years:
Without
control over the fuel quality and its preparation there will be no
commercialisation, not even of process heat gasifiers.Users don't put up with
flames going on and off several times a day or hour, just because the fuel
preparation is insufficient. Not to mention the extrem health hazard
cerated by
this on and off operations. In the case of gas storage there will be an
average
gas quality from on and off "good" gas generation.
How much energy do you need.??? Well, we still own our paradise in Boracay
in the
Philippines. If there, we live on 250 Wh of electricty a day from PV. Most
of it
goes to the laptop and pumping rain water that has been collected in a 50 cbm
storage tank to the top of the hill to get 3 bar pressure on the water supply
line. The 30 litre gas refrigiator consumes 1 bottle of LPG (15 kg) per
month,
and keeps the beer cold. Considering a cold wave of 25 C during winter time
(September to January) space heating is less important. Cheers A.Kaupp

Reedtb2@cs.com wrote:

> Dear Peter Davies and all Responders:
>
> I (and Community Power and the Biomass Energy Foundation) appreciate all the
> great comments and suggestions for gas storage that have appeared this week.
>
> I have been very actively building gasifiers and stoves and generators this
> last year with BEF and CPC. Last week I suggested to my wife, Vivian, that
> we buy or build an alternate energy cabin close to our home in Colorado,
> probably in the mountains and close to our home in Golden, and not requiring
> a so called Sport Utility Vehicle, (SUV = Silly, Ugly Vanity) to access.
>
> Gas is capable of supplying all my needs, as witness any Motorhome or house
> trailer operating with propane.
>
> I plan to install a 1 day gas storage unit that I would fill daily from a
> small gasifier before breakfast. It would then run cooking, mantle lamps, a
> micro generator for communication and a gas refrigerator.
>
> Gasification of 1 kg of biomass will generate 2.5 m3 of gas or 1 kWh of
power
> or 5 kWh of heat. How much energy will I need for the good life in the
> woods?
>
> ~~~~~~
>
> I have been storing up all these comments on gas storage and web pages on
gas
> storage in my email directory. Isn't it marvellous that the whole world has
> become a connected community of ideas. After all, behind every detail of
our
> current civilization lies plans, testing etc.
>
> It crossed my mind that we could even have a world conference on GAS
STORAGE.
> We might get a budget of $100K from NREL or DOE. Lots of people would like
> to travel to Colorado to yak about the commercial and environmental and
> efficiency aspects of gas energy storage.
>
> But then, by Email we have already had that conference. Keep the ideas
> flowing,....
>
> TOM REED

From vvnk at teri.res.in Mon Apr 19 02:14:58 1999
From: vvnk at teri.res.in (V V N Kishore)
Date: Tue Aug 31 21:36:18 2004
Subject: GAS-L: Re: Onsite gas storage
Message-ID: <199904190614.CAA05949@solstice.crest.org>

id BAA03577
Sender: owner-stoves@crest.org
Precedence: bulk

I do not agree that the commercialisation problem could be solved by
providing on-line gas storage,mainly because of space requirements and the
additional costs.The discussion I had with Al Kaupp some months ago was
useful and subsequently one of our users solved the problem of fuel quality
by tying up with an agent for supply of cut wood.Of course, there is a
small additional price to pay,but this more than offsets the 60% fuel
saving he has with the gasifier.By the way,if the flame keeps going on and
off for whatever reason,then the gasifier is obviously a
hoax.Commercialisation is a far cry for the supplier or developer of such a
gasifier system.
The problems associated with commercialisation of gasifiers are far
from over.However,our experience showed that there is more than one way of
solving these problems,and the solution does not (and should not) always
come from the academic circles .

>>> Albrecht Kaupp <eta-pet@eta-team.com> 04/18/99 11:42AM >>>
Tom, you have a point here. Looking at the major bottle neck of
commercalisation
of small scale gasification- the difficulties to keep the process continously
going due to little control over the fuel quality- the best would be gas
storage
(for small consumption only). A recent pretty frank discussion about the
ongoing
commercialisation of process heat gasifiers for the silk industry in India
showed
the usual difficulties that have been well known over the last 60 years:
Without
control over the fuel quality and its preparation there will be no
commercialisation, not even of process heat gasifiers.Users don't put up with
flames going on and off several times a day or hour, just because the fuel
preparation is insufficient. Not to mention the extrem health hazard
cerated by
this on and off operations. In the case of gas storage there will be an
average
gas quality from on and off "good" gas generation.
How much energy do you need.??? Well, we still own our paradise in Boracay
in the
Philippines. If there, we live on 250 Wh of electricty a day from PV. Most
of it
goes to the laptop and pumping rain water that has been collected in a 50 cbm
storage tank to the top of the hill to get 3 bar pressure on the water supply
line. The 30 litre gas refrigiator consumes 1 bottle of LPG (15 kg) per
month,

and keeps the beer cold. Considering a cold wave of 25 C during winter time
(September to January) space heating is less important. Cheers A.Kaupp

Reedtb2@cs.com wrote:

> micro generator for communication and a gas refrigerator.
>
> Gasification of 1 kg of biomass will generate 2.5 m3 of gas or 1 kWh of
power
> or 5 kWh of heat. How much energy will I need for the good life in the
> woods?
>
> ~~~~~~
>
> I have been storing up all these comments on gas storage and web pages on
gas
> storage in my email directory. Isn't it marvellous that the whole world has
> become a connected community of ideas. After all, behind every detail of
our
> current civilization lies plans, testing etc.
>
> It crossed my mind that we could even have a world conference on GAS
STORAGE.
> We might get a budget of $100K from NREL or DOE. Lots of people would like
> to travel to Colorado to yak about the commercial and environmental and
> efficiency aspects of gas energy storage.
>
> But then, by Email we have already had that conference. Keep the ideas
> flowing,....
>
> TOM REED

Gasification List SPONSORS and ARCHIVES

http://www.crest.org/renewables/gasification-list-archive

From rknecht at mines.edu Mon Apr 19 16:59:45 1999
From: rknecht at mines.edu (Bob Knecht)
Date: Tue Aug 31 21:36:18 2004
Subject: EPICS Stove Class at CSM
In-Reply-To: <d9cbc6c.36ff85e3@cs.com>
Message-ID: <371B99D7.6113BA3F@mines.edu>

Tom,

I have addressed this to you but wanted to answer your challenge with two notes. The first will be a
quick overview of the Design (EPICS) program and the advantages of our relationship to STOVES. The
second is to invite all the "stove" folks in the Denver-Golden-Boulder area to an exhibition of four
stoves designed, constructed and tested by four teams of second-year students at CSM.

The Design (EPICS) program builds a student's confidence to apply fundamental concepts and to solve
open-ended problems. To help students become skilled at this process, we have them learn through
practice. This process requires thoughtful contribution from many perspectives-material, analytical,
historical, aesthetic, ethical, structural, and creative. In addition, actual engineering problems are
open-ended in the sense that significant features of design problems are never quite the same from
project to project. It is never the case that only one acceptable solution can be identified with
absolute certainty. The program covers the first two year of the students course of studies and gives
them an opportunity to decide if engineering is truly for them.

Students not only apply their technical knowledge but must also communicate their ideas. They work
with clients and learn to negotiate the specifications and performance criteria for a design. They
communicate in teams to distribute the work and to assure that quality is not lost in the exercise. We
try to find projects, like the stove project, that challenges them to go beyond their classroom
learning and to build skills in self-learning. All of these exciting components make up what I
consider to be the heart of engineering design.

The stove project requires the students to challenge themselves creatively and technically. These
students have only been exposed to math, chemistry and physics. They need to fall back on these basics
to understand the concepts of pyrolysis and combustion. They use these skills to explore the
literature and to educate themselves about the process and operations of the stove. They build
prototypes to play with the mechanical aspects of the stove. They must also look at the regulatory and
marketing issues which push them beyond the boundaries of their traditional education. These four
teams have create four stoves that have unique functions characteristic of their teams. Since this is
our first exposure to "stoves," it has been a wonderful learning experience. The students have develop
several recommendations for projects for the future, which I will address to you and Ron after the
semester has ended.

I would like to invite you and all the "stove" participants to a poster and exhibition of four stoves
designed, constructed and tested by these teams. The session will be held on the Mines campus as
follows:

Date: April 29, 1999
Time: 8:00 to 9:15 Poster Session and Discussion with the Teams
9:15 Lighting of the stoves and test to boil water.
Location Hall of Justice, Room 124
17th and Arapahoe
Golden, CO
We hope that a fair number of local "stove" people can attend and meet the student and me. We would
like to discuss the stoves as well as projects for the future. Those who would like can contact me for
more information.

Have a great day.

Bob K.

From english at adan.kingston.net Tue Apr 20 07:30:08 1999
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:36:18 2004
Subject: (Fwd) Request for Charcoal Kiln Plans
Message-ID: <199904201130.HAA24401@adan.kingston.net>

Please I need help in constructing a steel charcoal kiln . I am
interested in producing charcoal in semi rural settings cause I have
accessibility to a lot of wastewood. Please if possible send plans I can
use to construct the kiln. I do not want to use the earth pit method
cause I know it is very inefficient.
Also I am looking for equipment to briquette charcoal fines. I am
lookig for already tested equipment that I can buy from an equipment
manufacturer. I am writing from West Africa. Please treat request as
urgent

Thanks

Tunde Olaniyan
tsquare@infoweb.abs.net

From elk at net2000ke.com Tue Apr 20 12:19:16 1999
From: elk at net2000ke.com (Elsen Karstad)
Date: Tue Aug 31 21:36:18 2004
Subject: Charcoal fines Briquetting Equipment
Message-ID: <199904201621.TAA28935@net2000ke.com>

From cree at dowco.com Tue Apr 20 12:43:42 1999
From: cree at dowco.com (John Olsen)
Date: Tue Aug 31 21:36:18 2004
Subject: Charcoal fines Briquetting Equipment
Message-ID: <003b01be8b4d$0b9661a0$1f5817cf@olsen>

Hi Elsen,
( 8 GIF's sent seperately to this note).

We have just started manufacturing the
"SunLog" portable compactor,( 2 man operation) on an Indian
reserve in Canada, and hope to sell it
around the World, especially to Aboriginal peoples.
Our machine compresses Bio-waste, Sawdust, Charcoal
Dust, Peanut Shells, Walnut shells, Hemp Hurds,
Rice Husks, etc., into burnable
logs.
John Olsen/Cree
Industries/cree@dowco.com

From costaeec at kcnet.com Tue Apr 20 16:12:29 1999
From: costaeec at kcnet.com (Jim Dunham)
Date: Tue Aug 31 21:36:18 2004
Subject: Charcoal fines Briquetting Equipment
Message-ID: <001c01be8b6f$c751a540$6c65f0d1@default>

Elston,

We mailed (3/19/99) you a complete packet of information on
all known manufacturers of briquetting equipment, as well as materials related
to densification of all biomass materials.

It should have reached you by now, but apparently has not. So
sorry! Will send additional package and hope for better mail
service.

Best regards,

Jim Dunham
Environmental Engineering Corp.

<BLOCKQUOTE
style="BORDER-LEFT: #000000 solid 2px; MARGIN-LEFT: 5px; PADDING-LEFT: 5px">
-----Original Message-----From:
Elsen Karstad <<A
href="mailto:elk@net2000ke.com">elk@net2000ke.com>To: <A
href="mailto:stoves@crest.org">stoves@crest.org <<A
href="mailto:stoves@crest.org">stoves@crest.org>Date:
Tuesday, April 20, 1999 10:24 AMSubject: Charcoal fines
Briquetting Equipment
Tunde Alaniyan
Asks:>Also I am looking for equipment to briquette
charcoal fines. I am>lookig for already
tested equipment that I can buy from an equipment>manufacturer. I am writing from West Africa. Please treat request
as>urgent.I am still
looking as well- it's been a year since I first put my request to the list,
and still no response. There must be a few list members that have contacts
with manufacturers of equipment such as this.... I have 'reinvented' the
extruder, but I'm sure that there's better than this out there.... I'm
looking for something that can briquette up to 2 tons per hour of clay-bound
charcoal fines....help!elk~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Elsen L. Karstad , P.O. Box
24371 Nairobi Kenyaelk@net2000ke.com tel/fax (+ 254 2)
884437

From woodcoal at mailbox.alkor.ru Tue Apr 27 08:33:35 1999
From: woodcoal at mailbox.alkor.ru (Woodcoal)
Date: Tue Aug 31 21:36:18 2004
Subject: EPICS Stove Class at CSM
Message-ID: <01be90aa$42b8cd00$LocalHost@22>

Dear Bob,
I teach in academy many years. I very much like your way to make the
students as the engineers. It is very good experiment and I believe in its
large efficiency. The performance of this work is possible, if there are
materials, machine tools and, maybe, ancillary workers. But method is simply
magnificent.
Sincerely yours, Yury Yudkevitch, Dr., ass. Prof.
Department of Forest Chemical Technology,
St.-Petersburg Forest Technical Academy(Russia)

Bob Knecht <rknecht@mines.edu> Reedtb2@cs.com <Reedtb2@cs.com>
larcon@sni.net <larcon@sni.net>; stoves@crest.org <stoves@crest.org>
20 . 04 1999 1:03
Theme: EPICS Stove Class at CSM

>Tom,
>I have addressed this to you but wanted to answer your challenge with two
notes. The first will be a
>quick overview of the Design (EPICS) program and the advantages of our
relationship to STOVES. The second is to invite all the "stove" folks in
the Denver-Golden-Boulder area to an exhibition of four
>stoves designed, constructed and tested by four teams of second-year
students at CSM.
>The Design (EPICS) program builds a student's confidence to apply
fundamental concepts and to solve open-ended problems. To help students
become skilled at this process, we have them learn through practice. This
process requires thoughtful contribution from many perspectives-material,
analytical,historical, aesthetic, ethical, structural, and creative. In
addition, actual engineering problems are open-ended in the sense that
significant features of design problems are never quite the same from
project to project. It is never the case that only one acceptable solution
can be identified with absolute certainty. The program covers the first two
year of the students course of studies and gives them an opportunity to
decide if engineering is truly for them.
>Students not only apply their technical knowledge but must also communicate
their ideas. They work
>with clients and learn to negotiate the specifications and performance
criteria for a design. They
>communicate in teams to distribute the work and to assure that quality is
not lost in the exercise. We try to find projects, like the stove project,
that challenges them to go beyond their classroom
>learning and to build skills in self-learning. All of these exciting
components make up what I
>consider to be the heart of engineering design.
>The stove project requires the students to challenge themselves creatively
and technically. These
>students have only been exposed to math,chemistry and physics.They need to
fall back on these basics to understand the concepts of pyrolysis and
combustion. They use these skills to explore the
>literature and to educate themselves about the process and operations of
the stove. They build
>prototypes to play with the mechanical aspects of the stove.They must also
look at the regulatory and
>marketing issues which push them beyond the boundaries of their traditional
education. These four
>teams have create four stoves that have unique functions characteristic of
their teams. Since this is
>our first exposure to "stoves," it has been a wonderful learning
experience. The students have develop
>several recommendations for projects for the future, which I will address
to you and Ron after the
>semester has ended.
>I would like to invite you and all the "stove" participants to a poster and
exhibition of four stoves
>designed, constructed and tested by these teams. The session will be held
on the Mines campus as
>follows:
>
> Date: April 29, 1999
> Time: 8:00 to 9:15 Poster Session and Discussion with the Teams
> 9:15 Lighting of the stoves and test to boil water.
> Location Hall of Justice, Room 124
> 17th and Arapahoe
> Golden, CO
>We hope that a fair number of local "stove" people can attend and meet the
student and me. We would ike to discuss the stoves as well as projects for
the future. Those who would like can contact me for more information.
>Have a great day.
>Bob K.

From dstill at epud.org Wed Apr 28 00:32:28 1999
From: dstill at epud.org (Dean Still)
Date: Tue Aug 31 21:36:18 2004
Subject: Report on Honduran stoves
Message-ID: <000101be9131$a4088780$b30e66d1@default>

It's been a while since I checked in to the list and I'd like to catch up on
Aprovecho's activity regarding stoves that are now being built in Honduras.
We are helping with different groups who plan to all together build more
than a thousand stoves.

It's interesting to think about these stoves since two of them are covered
with a "plancha" or grill. Using a plancha immediately means that the stove
will be less fuel efficient since heat only contacts the bottom of the pots.
Better fuel efficiency can be obtained by exposing the sides of the pot as
well to the hot flue gases.

But it is important to many folks to keep pots clean and it is great to get
all of the smoke out of the kitchen by using a chimney through the roof or
wall. By placing many pots on the plancha the stove actually does pretty
well.

Four stove designers were in Honduras for up to three months. Dr. Larry
Winiarski was with them for a month. Two basic changes were made in the
normal plancha stove: a "Rocket" type combustion chamber and chimney were
installed in the brick body of the large stove (increases combustion
efficiency) and heat transfer to the plancha was improved by forcing hot
flue gases to pass directly under the whole plancha in a narrow gap.

Building the stove body from inexpensive brick speeds up the building
process. The inner working parts of the stove were made from stainless
steel, which for some reason was inexpensive in Tegucigalpa. But it became
apparant that the 304 stainless wouldn't last very long. Peter Scott and
Mike Hatfield went exploring and found a group called Nueva Esperanza who
make ceramic stove parts that have a very good reputation for durability and
they plan to use these ceramic liners.

This group of women learned their trade in Guatemala building ceramic parts
for Lorena stoves. They have been making ceramic stove parts in Honduras for
more than ten years and have a great recipe involving horse manure, sand,
clay and tree gum. The parts are beautiful and functional.

We have a bunch of these ceramic parts and are subjecting them to stress
tests now at Aprovecho. They are holding up very well! Imagine a really
efficient stove built entirely out of clay, insulated with wood ash. It's a
A.T. dream come true.

We are going to make a bunch of stoves available all the way from a single
pot Rocket with an optimized skirt-the most fuel efficient- to Lorena type
stoves that, like the Rocket, separate the heat from the high mass stove
body and try to push as much heat as possible into the pots, even through a
plancha.

It would be interesting to see if dropping the pots down to the level of the
handles in the plancha would be acceptable. In this way much greater rates
of heat transfer are possible. Well see...

Anyway, It's always interesting. Peter returns in three weeks and the Mike
follows in a month or two, possibly with Larry. We are writing up the
experience with pictures, drawings. If anyone wants the report please
contact Aprovecho apro@efn.org

By the way, the plancha stove makes a very inexpensive way ($20) to
replicate the old fashioned cooking stoves that were popular and now cost so
much. And it boils water much faster.

Best Regards,

Dean Still

From Reedtb2 at cs.com Wed Apr 28 09:40:56 1999
From: Reedtb2 at cs.com (Reedtb2@cs.com)
Date: Tue Aug 31 21:36:18 2004
Subject: Pyrolysis, Gasification and Combustion
Message-ID: <4e2e82a.245869d8@cs.com>

Dear Friends in Gasification and Stoves:

I woke up this morning trying to think clearly about some aspects of
gasification and winding up thinking about the words we use. Each of us has
a slightly or very different use for the words on which our thinking is
based. There can be disagreement about facts, but often disagreements come
down to different understanding of the words.

So I have made myself a glossary of our words as intend to use them. I am
also attaching it as a MSWord file. I would appreciate your comments,
agreements, disagreements, suggestions etc. Please bring up new related
words with your definitions....

Yours truly, TOM REED
BEF

GLOSSARY: CLEAR THINKING IN PYROLYSIS, GASIFICATION AND COMBUSTION
(PYROLYSIS, GASIFICATION AND COMBUSTION)

I am convinced that biomass processes are much more complex than
nuclear energy. In a few decades, Einstein, Plank and others formulated all
of modern Physics, based on the clear ideas of classical physics.

In the 10,000 years of the development of civilization Humans have
only begun to understand the processes of pyrolysis, gasification and
combustion, PGC. (I put these important words in this order, because you
can't have combustion without a degree of gasification and you can't have
gasification without pyrolysis.)

Clear thinking is based on an exact understanding and definition of
the words we use. Muddy words lead to muddy thinking. On this basis, I will
here define or re-define the words we need for clear thinking in pyrolysis,
gasification and combustion.

Unfortunately, the definitions of words are in the form of other
words which makes cleaning out the mud difficult and could be circular.
Eventually however, you get down to works that everyone agrees on, physical
referants that we can point to and then the disagreement stops.
· PYROLYSIS: The breaking down of materials by heat, whatever the source, to
yield volatiles and charcoal
· VOLATILES: The vapor and gas that emerges from the biomass (largely
between 200 and 400°C. Note that "volatiles" includes both gas and vapor,
while "vapor" is only the fraction that is liquid at room temperature.
· VAPOR: Chemicals that are liquid at room temperature but gases at higher
temperature. (See Tar, wood oil and wood tar).
· TAR: A pejorative term for the heavier vapor components. I prefer "wood
tar" for the high temperature vapors from processes over 700°C and "wood oil"
for the vapors from processes (fast pyrolysis) operating below 600°C.
· Wood tar (Biomass tar): Polynuclear aromatics (naphthalene, anthracene
etc.) produced from vapors above 700°C. Analogous to coal tar.
· Wood oil (Biomass oil, biocrude): The monomers, oligomers and fragments of
the constituents of biomass cellulose, hemicellulose and lignin. Analogous
to coal oil.
· GAS (Permanent gas): Chemical compounds that remain in the gas phase below
0°C .
· CHARCOAL: The largely carbon, but some mineral material resulting from
pyrolysis
· XCOAL: A more accurate description of charcoal in which X denotes the
degree of conversion - yet to be more accurately defined
· GASIFICATION: Conversion of biomass to gas (and accidentally ash, char-ash
and vapors (tars) (I have in the past used the terms "gastarifier" for
updraft gasifiers which produce 20% tar; and "gascharifiers" for downdraft
gasifiers, which produce 5-10% unconverted char-ash.
· ASH: The mineral content of biomass, typically silicon dioxide, CaO, Na2O,
K2O, P2O5 etc.
· CHAR-ASH: The material left after high temperature gasification
· COMBUSTION: The conversion of char, tars and gases to heat, CO2 and H2O,
the ultimate fate of most thermal and other energy conversion of biomas.

From Reedtb2 at cs.com Thu Apr 29 09:34:35 1999
From: Reedtb2 at cs.com (Reedtb2@cs.com)
Date: Tue Aug 31 21:36:19 2004
Subject: Top lighting Honduran stoves
Message-ID: <561e5eb.2459b9b3@cs.com>

Dear Dean et AL:

I am glad to see stoves developed in the 1980s being used for the desparate
victims of Huricane Mitch and other users.

However, I wonder how many people have tried TOP LIGHTING these stoves.
Spread some dry kindling on top, preferably soaked in vegetable or animal
fat, alcohol or kerosene and light the fire.

If you do this the stove takes on the nature of a gasifier (I call it an
"inverted downdraft gasifier"; Ron Larson likes to call it a charcoal making
stove, others call it top burning. Each blind man to his own elephant
appendage.)

The fire works its way down through the layers of fuel and the gases come to
the surface by natural convection and are burned in ambient air. If there is
too limited access to ambient above the fire, the fire will be rich, but not
as rich as with conventional bottom lighting.

Bottom lighting releases the 80% volatile component of the wood in the first
25% of the burn and there is usually not enough air to burn it. Then the
charcoal burns at reduced levels the remainder of the time. With top
lighting the fire progresses steadily downward, releasing a constant supply
of gas which burns above the charcoal. After the volatiles are all burnt,
the bottom air burns the charcoal and continues to heat at a lower level.

I am not familiar with all the stoves you mention, but I hope you will try a
few runs on each and let us know what happens.

Yours truly, TOM REED
BEF

It would be interesting to see if dropping the pots down to the level of the
handles in the plancha would be acceptable. In this way much greater rates
of heat transfer are possible. Well see...

By the way, the plancha stove makes a very inexpensive way ($20) to
replicate the old fashioned cooking stoves that were popular and now cost so
much. And it boils water much faster.

Best Regards,

Dean Still

From rmiranda at sdnnic.org.ni Thu Apr 29 09:43:54 1999
From: rmiranda at sdnnic.org.ni (Rogerio Miranda)
Date: Tue Aug 31 21:36:19 2004
Subject: Report on Honduran stoves
Message-ID: <3.0.5.32.19990428225326.0086be60@pop.sdnnic.org.ni.>

Dean:

I am partircularly happy about APROVECHO´s contribution to the development
of the plancha stove in Honduras. Back in 1995 I with the help of a young
canadian volunteer from AFS (Jennifer Melanson) introduced the plancha
stove to Tegucigalpa. We did (in colaboration with ADHESA and Stuart
Conway) a pilot project in Suyapa community. At that time and still today
lots of people tell us that plancha isn´t efficient enough, due the lack of
direct contact of the flame with the pot bottom and also due the large
surface of the plancha exposed. I understood that, but also realized that
plancha was more convenient for tortilla making, to keep many pots warm
around the main one being cooked, and most important, have much low
emissions in comparation to lorena type stove. I still believe that keeping
a health and clean environment is the main attractive feature for the new
generation of urban woodstoves users.

Here in Nicaragua we have just surveyed 2025 urban households (plus 800
being surveyed right now) about fuel uses and preferences. Basicaly, there
is a trend from fuelwood to LPG in the urban area (in average today 50%
uses fuelwood, 30% LPG and 20% fuelwood + LPG), but we are in a transition
phase in which people are using both fuels.

we asked people about why do they use fuelwood or LPG, and the main answers
were:

1. LPG is cleaner and fuelwood dirt
2. Fuelwood although more expensive at the end of the month, but more
affordable to buy everyday (US$ 0.10-0.50), while LPG is less affordable
when you need it (US$ 5.5/cilinder))
3. LPG is not available everywhere and can run out without expecting, while
fuelwood is plenty available and predictable
5. LPG is dangerous (explodes)
6. Fuelwood you don´t need to invest in equipment, while a LPG stove cost
about US$ 70-120
7. fuelwood can be bought by a children at the grocery store in the corner.
while LPG needs a man or a vehicle to transport it
8. Fuelwood gives a better taste to the food, and it is a rural tradition
9. fuelwood stove keeps the food warm longer, while LPG cool down quickly

another interesting information is that 95% of the fuelwood users doesn´t
know anythingh about improved woodstove, but when informed about the
advantages of it and asked about their choice today, most of them prefered
a improved woodstove than a LPG stove. Even when the majority recognized
that LPG is a better fuel if they would have the conditions.

I hope that APROVECHO people will come to Nicaragua as well this next mission.
we need very much the loroca.

good job

rogerio

>From: "Dean Still" <dstill@epud.org>
>To: <stoves@crest.org>
>Subject: Report on Honduran stoves
>Date: Tue, 27 Apr 1999 21:43:13 -0700
>X-MSMail-Priority: Normal
>X-Mailer: Microsoft Outlook Express 4.72.3110.5
>X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3
>Sender: owner-stoves@crest.org
>
>It's been a while since I checked in to the list and I'd like to catch up on
>Aprovecho's activity regarding stoves that are now being built in Honduras.
>We are helping with different groups who plan to all together build more
>than a thousand stoves.
>
>It's interesting to think about these stoves since two of them are covered
>with a "plancha" or grill. Using a plancha immediately means that the stove
>will be less fuel efficient since heat only contacts the bottom of the pots.
>Better fuel efficiency can be obtained by exposing the sides of the pot as
>well to the hot flue gases.
>
>But it is important to many folks to keep pots clean and it is great to get
>all of the smoke out of the kitchen by using a chimney through the roof or
>wall. By placing many pots on the plancha the stove actually does pretty
>well.
>
>Four stove designers were in Honduras for up to three months. Dr. Larry
>Winiarski was with them for a month. Two basic changes were made in the
>normal plancha stove: a "Rocket" type combustion chamber and chimney were
>installed in the brick body of the large stove (increases combustion
>efficiency) and heat transfer to the plancha was improved by forcing hot
>flue gases to pass directly under the whole plancha in a narrow gap.
>
>Building the stove body from inexpensive brick speeds up the building
>process. The inner working parts of the stove were made from stainless
>steel, which for some reason was inexpensive in Tegucigalpa. But it became
>apparant that the 304 stainless wouldn't last very long. Peter Scott and
>Mike Hatfield went exploring and found a group called Nueva Esperanza who
>make ceramic stove parts that have a very good reputation for durability and
>they plan to use these ceramic liners.
>
>This group of women learned their trade in Guatemala building ceramic parts
>for Lorena stoves. They have been making ceramic stove parts in Honduras for
>more than ten years and have a great recipe involving horse manure, sand,
>clay and tree gum. The parts are beautiful and functional.
>
>We have a bunch of these ceramic parts and are subjecting them to stress
>tests now at Aprovecho. They are holding up very well! Imagine a really
>efficient stove built entirely out of clay, insulated with wood ash. It's a
>A.T. dream come true.
>
>We are going to make a bunch of stoves available all the way from a single
>pot Rocket with an optimized skirt-the most fuel efficient- to Lorena type
>stoves that, like the Rocket, separate the heat from the high mass stove
>body and try to push as much heat as possible into the pots, even through a
>plancha.
>
>It would be interesting to see if dropping the pots down to the level of the
>handles in the plancha would be acceptable. In this way much greater rates
>of heat transfer are possible. Well see...
>
>Anyway, It's always interesting. Peter returns in three weeks and the Mike
>follows in a month or two, possibly with Larry. We are writing up the
>experience with pictures, drawings. If anyone wants the report please
>contact Aprovecho apro@efn.org
>
>By the way, the plancha stove makes a very inexpensive way ($20) to
>replicate the old fashioned cooking stoves that were popular and now cost so
>much. And it boils water much faster.
>
>Best Regards,
>
>Dean Still
>
>
>
>Stoves List SPONSORS and ARCHIVES:
>http://solstice.crest.org/renewables/stoves-list-archive/
>Stoves Webpage
>http://www.ikweb.com/enuff/public_html/Stoves.html
>For information about CHAMBERS STOVES
>http://www.ikweb.com/enuff/public_html/Chamber.htm
>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Rogerio Carneiro de Miranda
Coordinador Proyecto EMOLEP
CATIE - PROLEÑA
Apartado Postal C-321
Managua, Nicaragua
TELEFAX (505) 276 2015, 270 5448
EMAIL: rmiranda@sdnnic.org.ni
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Stoves List SPONSORS and ARCHIVES:
http://solstice.crest.org/renewables/stoves-list-archive/
Stoves Webpage
http://www.ikweb.com/enuff/public_html/Stoves.html
For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From karve at wmi.co.in Fri Apr 30 00:51:40 1999
From: karve at wmi.co.in (karve)
Date: Tue Aug 31 21:36:19 2004
Subject: Report on Honduran stoves
In-Reply-To: <000101be9131$a4088780$b30e66d1@default>
Message-ID: <37293671.FA14A7DD@wmi.co.in>

Dear Dr. Still,
We have a manufacturer who makes a pottery liner version of our
single pot
hole chimneyless stove Grihalaxmi. The ceramic one is a two-piece stove,
the lower piece
is the firebox and the upper piece the stove mouth. We have found that:
(a) The stove must be fixed into a mud platform, otherwise it breaks
into pieces
under the weight of the cooking pot.
(b) Even the fixed stove develops cracks in the upper piece with
repeated use.
The manufacturer came to us for help and we have suggested that the
upper piece
should be made out of three pieces to be put together while fixing the
stove in
the platform. The solution is now being field tested.
(c) In India, the clay stove is the cheapest one, the metal stove costs
about 1.3 times the clay one and the pottery liner stove costs 1.5 times
the
clay one.
(d) On the plus side for the ceramic stove, there is the insulation
advantage.
Also, one can guarantee accurate dimensions. It is easier to transport
and store. Although the design consists of several pieces, the assembly
is simple and the manufacturer provides a leaflet with instructions
which are quite adequate for the user.
We too have experimented with ceramic parts in a clay stove and that
works quite well, except for the cost enhancement. The durability
problems come in for a 100% ceramic stove. A clay stove body too
develops cracks with repeated use, but the user can easily repair it
using mud. That is not the case with the ceramic stove. Actually if the
stove is properly fixed, the cracks do not interfere much in the stove
operation. But the problem is that it is considered inauspicious to use
a cracked stove. We are facing similar problems in our attempts to
develop a low-cost baked clay design.
With regards,
Priyadarshini Karve

Dean Still wrote:

> Peter Scott and
> Mike Hatfield went exploring and found a group called Nueva Esperanza who
> make ceramic stove parts that have a very good reputation for durability and
> they plan to use these ceramic liners.
>
> This group of women learned their trade in Guatemala building ceramic parts
> for Lorena stoves. They have been making ceramic stove parts in Honduras for
> more than ten years and have a great recipe involving horse manure, sand,
> clay and tree gum. The parts are beautiful and functional.
>
> We have a bunch of these ceramic parts and are subjecting them to stress
> tests now at Aprovecho. They are holding up very well! Imagine a really
> efficient stove built entirely out of clay, insulated with wood ash. It's a
> A.T. dream come true.
>
> Best Regards,
>
> Dean Still
>
> Stoves List SPONSORS and ARCHIVES:
> http://solstice.crest.org/renewables/stoves-list-archive/
> Stoves Webpage
> http://www.ikweb.com/enuff/public_html/Stoves.html
> For information about CHAMBERS STOVES
> http://www.ikweb.com/enuff/public_html/Chamber.htm

BioEnergy Lists: Improved Biomass Cooking Stoves

November 1999 Biomass Cooking Stoves Archive