[Stoves] Version 2.0 of TLUD history is available

Fri Feb 19 09:38:58 CST 2016

Richard,

Thanks for the comments. A lot has changed indeed. One big change is what we
regard as acceptable living conditions and our ideas about the costs and
benefits of smoke going up through thatched roofs. Most of us probably
attributed the now familiar health effects of smoke to other causes. A lot
has been learned since those days. 

We also had different priorities then. The early 70s was a time in which we
were more concerned about building housing for people that improving cooking
efficiency. The focus was not necessarily on improved cookstoves.  We
designed modular rural housing for Costa Rica. We even built full scale
model houses here in Portland that we sent down as examples. Later at the
Mexican Forest service we looked for incentives for villagers to selling the
first log at the base of a tee for a higher value as solid wood instead of
ruining the log by cutting out the ocote, or resin rich "fatwood", found at
the base of a tree for cooking fuel. We encouraged them to use
pre-commercial thinnings for firewood instead. (Then the government
changed.) That was also the time when our friend Ben Bryant was finding
solutions for replacing corrugated roofing with local natural fibers. 

Tom

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of
Richard Stanley
Sent: Friday, February 19, 2016 6:07 AM
To: Stoves and biofuels network <stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Version 2.0 of TLUD history is available

Small world Tom:

 Ton de Wilde and colleagues were working on same thing with us in Tanzania
in the late 70's . Then there was little interest in improved cookstoves few
people lots of open cooking and plenty of wood. My how that has changed now
eh!

Richard Stanley

 Nicaragua 

On Feb 18, 2016, at 10:45 PM, Tom Miles <tmiles at trmiles.com
<mailto:tmiles at trmiles.com> > wrote:

Julien,

"What I think we need more of is help for the practical cookstove
developers." Indeed. 

Looking for help with cookstove development while working in forested areas
of rural Mexico in 1972-74 was something of a challenge. In the US in the
story of improved cookstoves were attempts at improved combustion like the
Lorena mud stove. While we worked with gasification from about 1976 to the
present and saw it applied to wood heating appliances in the US we didn't
see gasification applied to cookstoves until 1982-83 when I became
acquainted with the work at Eindhoven 1980-1987 which included downdraft
concepts. Their work was presented at European bioenergy conferences. 

http://www.cookstove.net/introduction.html

The stratified downdraft was being developed by Tom Reed at SERI to make
synthesis gases and was first demonstrated in 1982. We had a close
association with gasification work of all kinds during that period. My
experience with stoves in the 1980s was largely with various jikos including
the ceramic jiko. Baldwin's work published by VITA became a good combustion
reference for practitioners who knew about VITA, and the Appropriate
Development Groups like (ITDG). Governments and aid agencies invested in
stove programs at this time but eventually abandoned them because the impact
was not visible or measureable. As Paul has chronicled it was at this time
that Tom Reed started working with Fred Hottenroth and others who had an
interest in cookstoves. 

At some point about 1989 Tom cooked part of our dinner on the Sierra ZMart
stove in his kitchen. He then applied for funding through a public agency.
We were asked to vet the proposal. I remember at the time that we found very
little literature on a gasifying cook stove even though we had seen several
gasifying designs for wood heating appliances. It took months to get a stove
because they were hand made in batches. We followed the water boiling tests
procedures of the time. We were intrigued and impressed by clear
gasification and char burnout stages of the stove. Our correspondence and
tests covered the period of about 1990-1992. 

The interaction between engineering and design and field development and
testing was limited in global terms. Funding had a big impact on this. Most
of the work in the field was done by volunteers from non-profits and church
affiliated groups. The charitable work that has been done by these groups
has always been very impressive. About the time that we started this stoves
discussion list in 1994-1996 we began to see a slow increase in stoves
activity. As moderator Ron Larson did the community a greater service by
bringing people together inline and visiting them in the field. Ron, Alex
English and others were testing gasifying stoves at the time of the stoves
conference in Pune in 2000. Dean Still and Mark Bryden started ETHOS about
that time. Gasifying stoves struggled for attention with the growing
improvement of rocket stoves. I think that Boiling Point was still
"bubbling" and the Intermediate Technology Group became Practical Action.
HEDON was created.  The dream of increasing interaction in the field was
boosted with the Partnership for Clean Indoor Air and later the Global
Alliance for Clean Indoor Air. But it is still difficult for stove
developers to benefit from the big budgets being spent today on cookstove
development. At our recent ETHOS meeting stove developers, who mostly work
in the field, wondered how they could benefit from all the work being done
in the laboratories. So we still have the challenge.    

Tom    

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of
Julien Winter
Sent: Thursday, February 18, 2016 6:27 AM
To: Discussion of biomass cooking stoves <stoves at lists.bioenergylists.org
<mailto:stoves at lists.bioenergylists.org> >
Subject: [Stoves] Version 2.0 of TLUD history is available

Hi Paul;

Thanks for your thorough account on the development of TLUD cookstoves.  It
is well illustrated and rich in information.

For me (as an outsider soil scientist joining in), what stands out in the
history of TLUD cookstove development, and biomass cookstove development in
general is the disconnect between two communities (1) the practical
cookstove developers, on the one hand, and (2) the combustions scientists
and engineers on the other side.

What were ostensibly "TLUDs" existed in several research laboratories since
the 1940s.  After the oil crisis in 1973, there was a big increase in
research interest in biomass energy.  TLUDs were laboratory models of moving
grate gasifiers.  An influential paper appeared in 1984:
Stubington, JF; Fenton, H.  1984. Combustion Characteristics of Dried and
Pelletized Bagasse.  Combustion Science and Technology  37: 285-299   DOI:
10.1080/00102208408923758

After that, forced draft TLUD research took off in the academic world and
the 70+ papers (in English) have been published.

Unfortunately, nobody in the world of practical stove development was
reading those papers, either because they didn't have access through
paywalls, and/or because they lacked the scientific training to understand
them.

In the academic world (asside from health-oriented research on emissions,
and sociology), there has been almost no reaseach specifically on biomass
cookstoves and their mechanism of combustion.  Only recently has this
strated to change with graduate students working on TLUD stoves:

Huangfu, Y; Li, H; Chen, X; Xue, C; Chen C; Liu, G.    2014.  Effects of
moisture content in fuel on thermal performance and emission of biomass
semi-gasified cookstove. Energy for Sustainable Development 21: 60-65
Varunkumar, S; Rajan, NKS;  Mukunda, HS.  2011b. Single particle and packed
bed combustion in modern gasifier stoves-density effects.      Combustion
Science and Technology  183: 1147-1163. 
Varunkumar, S; Rajan, NKS; Mukunda, HS.  2011a.  Experimental and
computational studies on a gasifier based stove. Energy Conversion and
Management 53: 135-141
Varunkumar, S; Rajan, NKS; Mukunda, HS.  2013.  Universal flame propagation
behaviour in packed bed of biomass.  Combustion Science and Technology,
DOI:10.1080/00102202.2013.782297 

Fortunately, the combustion scientists are beginning to take an interest,
because  issues in Global ecology are becoming acute.  More graduate
students are appearing.

What I think we need more of is help for the practical cookstove developers.
There needs to be scientific capacity-building, access through the academic
paywalls, and access to basic measurement equipment.  There needs to be
strong system of mentoring around the World so that these two communities -
practicioners and scientists - become better connected and work together.

All the best,

Julien

-- 

Julien Winter
Cobourg, ON, CANADA

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