South/North Biomass

It has been fascinating to cross-pollinate learnings from biomass cook stoves typical of the Global South and biomass heating stoves used in the Global North.

Biomass cook stoves are often used indoors without chimneys. They are not usually closed boxes. Primary air cannot be limited when the fuel door is open. Cook stoves are also short, so the residence time of flame/air/fuel is very short. For these reasons, typical cook stove designs forced TLUD inventors Tom Reed and Ron Larson (and many others) to deep dive into other clean burning options, especially passing woodgas through burning charcoal followed by mixing with air jets.

New heating stoves are using the same techniques to achieve clean combustion. Up Draft heating stoves, like TLUDs, force wood gas up through burning charcoal and use forced draft jets to achieve needed mixing of fuel, air, and spark.  (Obernberger, Brunner, 2023)

ARC is studying up draft, side draft and down draft combustion techniques that find applications in both cook stoves and heating stoves. We do experiments on prototypes and the results suggest changes. Working on a TLUD type heating stove yesterday evolved into a new approach to cleaner burning Rocket cook stoves.