I was researching this a while back also for a different application , and agree this is a very good project..
As you said they are extremely efficient, and produce a Clean Hot Flame .
I believe there was a Charity mission of some kind that gave smaller versions of them away to poor people I think it was India or Africa ? so they could cook their meals, with just a couple of sticks.. not much wood at all.
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They do sell smaller ones made from Recycled and cut up PROPANE tanks , with legs.. not sure how good they are.
but they sell a lot of them on Ebay.. from what I read though they only heat like Water for soup, or maybe make Eggs while Camping.. they dont produce a lot of heat , not like a Propane flame, but considering the fuel is only some sticks , still pretty impressive , l however not enough to like DEEP Fry with Oil .. or cook large fish.
If you make a LARGER version, with some real BTU capabilities,
I would be most curious how it turns out.
Keep us posted.