ARC has been unpleasantly surprised on several occasions by the results of USAID field studies. For example:
- When a popular high mass Rocket stove (6-brick stove) used about as much wood to cook compared to open fires. In fact, the open fire outperformed or equaled the performance of all the high mass stoves!
- When even a low mass insulated Rocket stove (StoveTec) was not cleaner burning than open fires. For every kilogram of wood that was combusted, similar quantities of CO2, CO, CH4, TNMHCs, and PM were emitted. A 42% total reduction in PM2.5 and greenhouse emissions was the result of something like 40% better heat transfer efficiency, not improved combustion efficiency.
(In-Home Emissions of Greenhouse Pollutants from Rocket and Traditional Biomass Cooking Stoves in Uganda, USAID 2011)
- When the same StoveTec stove had more than twice the fractional Black Carbon content in its PM emissions (15.5%) compared to the traditional stove (7.2%) (In-Home Emissions of Greenhouse Pollutants from Rocket and Traditional Biomass Cooking Stoves in Uganda, USAID 2011)
At the same time, the bad news forced ARC to make better stoves! Thank you, USAID! For a list of more USAID Biomass Stove Field Studies, see our Publications page.
Next week in Part 2: the field informs the lab.