Before starting to develop cleaner burning cook stoves in the 2013-2015 DOE project, ARC researchers completed a survey of best performing existing stoves. Improving combustion efficiency to protect health (and climate) has continued as various cook stove organizations have worked tirelessly to meet the WHO 2015 PM2.5 Intermediate Emission Rate Target of 1.75mg/minute, calculated to protect health in homes using biomass to cook.
The results of the survey are described in Clean Burning Biomass Cookstoves, 2nd edition, 2021.
- With a 6mm channel gap pot skirt, many stoves scored close to 50% thermal efficiency.
- TLUDs were not able to achieve enough Turn Down Ratio (TDR) to simmer water.
- Burning wood does not emit much CO so meeting the WHO CO Target (.35g/min) was easy.
- Forced draft TLUDs scored between 2mg/min PM2.5 to around 5mg/min.
- Stoves with chimneys met the aspirational WHO PM2.5 Emission Target of 0.23mg/min since the smoke was transported outside.
SupaMoto Forced Draft TLUD Bests WHO Goals
The new SupaMoto stove from Emerging Cooking Solutions with combustion technology from partner company Zemission has made great progress! For information contact Mattias Ohlson at: email@example.com. As seen below, in Water Boiling Tests at ARC, the SupaMoto Forced Draft TLUD achieved:
- 51% to 56% thermal efficiency (without pot skirt)
- 0.1g/min to 0.6g/min for CO
- 0.19mg/min (simmer) to 1.11mg/min (high power) for PM2.5
- The temperature corrected time to boil the 5L of water was fast, about 18 minutes
As in the FD TLUD Mimi-Moto stove, turn down in the Supa-Moto is achieved by inserting an accessory into the combustion chamber. The Supa-Moto Turn Down Ratio (TDR) varied between 1.91 to 2.11. When a lid is used on a pot, a TDR of around 3 saves more fuel when a lower firepower is needed to simmer food to completion. Reducing the forced air jets in a TLUD does not create sufficient TDR.
It is so gratifying to witness progress! I never thought that we would see a biomass stove come so close to meeting the aspirational PM2.5 WHO Emission Rate Target. To test a stove that easily meets the Intermediate PM2.5 Target is amazing. Mattias and the Zemission team have moved TLUD technology forward and it is a very valuable achievement!
Thank you for your work! Learning how to cleanly combust biomass has important ramifications in all parts of the world now that climate change reinforces the importance of renewable biomass as a health and climate friendly energy source.