[Stoves] Banglalesh TLUD stove Re: [Stoves] No subsidies in TLUD char production

Thank you for the detailed report.  The non-metalic components are of great interest.

Question:   You wrote:

About 24 small holes in the side wall of the metal reactor make the gasification of chunks of wood more reliable, and less prone loosing the gas flame. 

Is that shown in a photo?   Or please describe with more detail.  AND is there also a gap (how large?)  for secondary air entry at the top of the reactor?

Of the current cost of about $20, please break that down into metal (what pieces?), cement/ceramics, and labor (and any other type of cost that you can estimate.).

Paul

Hello all;

Thanks for you comments on the Akha-Biochar Project in Bangladesh.

The cost and payback is not fully worked out, because it will take about a year for TLUD-biochar ecosystem to become established in community, and it will continue to evolve. The stove costs about $20 to make, this could be brought down as numbers of stoves increase.  Also, we are still at the stove-prototype stage, so we can expect some modifications and fine tuning.    Payback is developing, as farmers and gardeners discover the value of biochar for food production.  We have “Farmer Biochar User Groups” that are conducting field trials, so they can learn from first-hand experience what biochar can do for them.  There are also graduate students involved in gathering evidence to make recommendations on optimum application rates.  It could take a couple of years at any one location for the local population to be able to place their own value on biochar, and what they are willing to pay for it.  

Whether people use the char themselves or sell it depends on their personal opportunities.  There are many families that are landless. Presently, they see char sales as a way to earn cash or barter. They think that is a great idea; save fuel, cook faster, AND make biochar!  People with land, especially farmers, see biochar as a way of making permanent improvements to the quality of their land, so expect that using biochar could have very substantial impact on their family’s economic well being.

I have been advocating using biochar in composting, or mixing it with manure before it goes onto the field.  We need work on using it in human waste management.

There is no shortage of good soil scientists and agronomists in Bangladesh to work on biochar technology. 

The outer concrete cylinder of the Akha stove is cast.  We have made stoves with concrete reactors (lined with clay slip), but their smoke-free combustion was less reliable, and there were some gas burner issues to solve.  That is not to say that concrete reactors will not work, but they need quite a bit of research and development, and a laboratory.  Metal TLUD reactors, on the other hand, are well understood.  About 24 small holes in the side wall of the metal reactor make the gasification of chunks of wood more reliable, and less prone loosing the gas flame.  We use cast concrete (rather than clay) because it is easy to get concrete rings with flat surfaces at the top and bottom. The concrete components are made specifically for the Akha.  There are many small business around who can cast concrete.  

Mahbubul has been working with different ratios of Portand cement, sawdust and biochar dust in the concrete. The more organics, the lower the heat capacity and heat conductivity of the stove body. Micro porosity is supposed to make concrete more resistant heat by providing spaces for minerals to expand into.  Obviously there is a trade-off between adding organics and strength of the concrete.  Different recipes are being tested in the field.  It is all trial and error.

Mahbubul has also worked with local ceramic artisans to make the massive stove components from clay.  There very skilled people to work with, and kaolinitic clay, so ceramic components are possible.  The more metal components on the stove that we can replace with ceramics the better, because all metal in Bangladesh is imported.

The Akha is about 25% more efficient than a traditional stove.  The Akha has gone through a water-boiling test at a laboratory in Dhaka, and was about 30% efficient at getting energy from wood into the water.  The main view that the Akha saves 25% of the wood comes from household feedback. That is what the women tell us.

The Akha-Biocahr Project has funding for its current intervention until 2019. It is enough to see if the TLUD-biochar technology will take root.  If it does, then the technology may spread all by itself as local entrepreneurs see an opportunity.  In fact, I think that if these technologies viable, then they will out of our control and unstoppable.  The ‘market’ is 25 million homes.  All the same, I am trying to raise money so that Mahbubul and crew remain as proponents and stakeholders in what they started.  There is work to be done in developing compressed fuels, because there is not enough wood in the country.  We need to monitor the impact on forest cover, and make sure that poorest households don’t become energy-starved if the price of wood goes up.

One other thing that will push TLUD-biochar technology forward is that sea-level rise could flood a third of the country, so soil productivity needs to increase.

Cheers,

Julien.

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Julien Winter
Cobourg, ON, CANADA