Dear Mr. Kar, and to other Stovers.
Mr. Kar asked me a question, and I am sending the response to the larger
audience of the Stoves Listserv and for posting onto my
www.drtlud.com website.
while Jetter et al., 2012 (attached) classifies both HD4012 (Philips
forced draft) and Oorja as "variations of gasifier stove", some
experts (Mukunda et al., 2011) are of the opinion that HD4012 is an
in-situ combustion design while Oorja is a gasifier stove.
About your question, I basically agree with Dr. Mukunda, to whom I also
send my warmest regards. The term "in-situ" correctly distinguishes the
combustion from that of the TLUD gasifiers that have the migratory
pyrolysis front. They can all be gasifiers (depending on the
definition of gasifier), but they are not in the same categories.
There is a stove type that I call "fan-jet" stoves because high
turbulence of limited air is the key feature. And they are not really
top-lit. Those stoves are: Philips forced air, WorldStove Lucia
forced air, Ecococina of El Salvador, and the new BioLite stoves (all
have forced air, but Philips and WorldStove also have natural draft
units that are sometimes confused if we do not emphasize the forced air
versions.) The developers of each of those four stoves have patent
claims and are for-profit companies. They are quite distinct from the
TLUD stoves with fans or without.
If others want to propose a different name instead of "fan-jet", that is
fine. But do not call them "fan stoves" because there are simply too
many ways to have forced air. So many different stoves with fans should
not be lumped together.
The high turbulence is the way the fan-jet stoves get clean emissions,
but they do NOT function (at least not very well) as a TLUD stove with
the pyrolysis front moving downward in a stationary fuel pile. Fan-jet
stoves have their fire (hot spot) down near the bottom, even from the
beginning. That is why they can accept new amounts of fuel onto the top
of the hot spot.
Note that the Oorja stove is commonly ignited as a TLUD, but once the
pyrolysis front reaches the bottom, the forced air allows people to add
in small amounts of fuel (I call that "trickle fueling"). But it is
NOT operating any longer as a TLUD combustion device. It would be a
bottom-burning stove with well controlled air. And the bottom burning
is of hot charcoal, so the bottom of the stove is endangered. That is
why the Oorja stoves have a cast iron cup, to prevent destruction of the
lower part of the stove. The Tom Reed WoodGas Campstove is similar,
but without the cup.
The above comments will be clear to those who have seen these various
stoves in operation. And there does need to be a clear distinction
between the various types of stoves.
[To Mr. Kar:
It is a pleasure to meet you via email. At what TERI facility are you
located? I am a friend of Dr. Srinivas who was in southern India
(Bangalore ??) with TERI, but is now in Delhi. ]
Paul / Dr TLUD
Paul S. Anderson, PhD aka "Dr TLUD"
Email: [email protected] Skype: paultlud Phone: +1-309-452-7072
Website: www.drtlud.com
On 10/30/2012 8:42 AM, abhishek kar wrote:
Dear Dr. Anderson,
I am an Associate Fellow with The Energy and Resources Institute (TERI
www.teriin.org <http://www.teriin.org> ), India. I have been working
on various technical and dissemination aspects of improved cook-stoves
in India and Kenya with focus on black carbon and market value chain.
I have recently published a paper on the linkage between black carbon
and cookstoves (attached-Kar et al., 2012). I was also the site
manager of a field research project related to black carbon
mitigation- Project Surya www.projectsurya.org
<http://www.projectsurya.org>
As the world's foremost authority on gasifiers for cooking
applications, can you share your approach for classification of stoves
as there seems to be grey areas in the classification.
For example, while Jetters et al., 2012 (attached) classifies both
HD4012 (Philips forced draft) and Oorja as "variations of gasifier
stove", some experts (Mukunda et al., 2011) are of the opinion that
HD4012 is an in-situ combustion design while Oorja is a gasifier stove.
Based on my limited understanding of micro-gasification, I wonder if
original design intent is more relevant or style of operations that
drives the classification approach. How do we distinguish between
HD4012 and Oorja if both stoves have batch fuel loading and top lit
operations using same fuel type? I keenly look forward towards your
expert views in this regard.
Warm Regards,
Abhishek Kar
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