[Stoves] About "fan-jet" stoves Re: Request

[Paul Anderson]

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:  psanders at ilstu.edu   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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