[Stoves] Fwd: The Akha TLUD – Biochar Project in Bangladesh.

When you look at the Akha you will see some areas for improvement.  It is a work in progress.  It can take some local experience before suggested new designs take hold.  Some new burners may be more efficient than the existing one, but too complex to become popular in a particular country.  Even a little bit of complexity may be too much for local stove-builders to accept.  It could be a challenge to replace an old design with a new one, once the old design has taken root in the population.  “If the old burner is ‘good enough’, why replace it?” 

Ideally, I think it is important to get good burner introduced in the first place, because once an idea is public, you can’t recall it.  However, the demand to introduce a new innovation can outrun the pace of research and development.  (Biochar is a good example.  Everybody wanted to use it before we adequately understood its environmental impact.)   There can also be a bit of reversal of priorities: before there is funding for research and development on a stove, it has first to be shown that the public wants it.  And, there can be a race among NGOs and businesses to be first.  So the first stove into homes is a Tier-3 stove. 

About the Akha and things to improve:  (1) It is using an old-style concentrator burner, so some flames get quenched on the bottom of the pot. (2) The riser-pot support needs to be made more efficient at transferring heat to the pot. (3) Primary air control is not as air-tight as it could be — however, there are 18 x 2 mm holes in the side walls of the reactor, so we really can’t shut the reaction down.  (The holes are a compromise to prevent combustion in the reactor from going out, and creating a lot of smoke.  That could cause major customer complaints).  They are working on it.

There is a need to develop compressed fuels in Bangladesh, because half of the biomass fuel currently being used in rural areas is low density plant residues.  People tend to burn leaves in the dry season, and save up wood for the rainy season.  We had hoped that the Akha would be twice as efficient as a traditional stove, so wood supplies would last longer.  However, the difference in efficiency in not yet that great.  That means that the Akha can only be used for half the year.  If compressed fuels are developed, we could double the production of biochar.   I expect that there has already been a lot of research on compressed fuels in Bangladesh (e.g. rice hull briquettes), but TLUDs and biochar produce a new demand that was not present in previous combustion stoves.  Biochar may provoke the production of new cooking fuels.