Entries by Kim Still

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Cleaner Burning Biomass Stoves: In Homes!

The British Petroleum clean burning Oorja FD-TLUD stove from India If protecting health and climate are important in stove projects, why not monetize the reductions of health/climate pollutants in carbon-offset projects? Only the reduction in fuel use earns carbon income now! With equal heat transfer efficiency, dirty burning stoves earn as much as clean burning stoves. […]

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Moving Forward: Thanks to Jim Jetter’s EPA Lab!

Champion (2021) average energy emission factors (g/MJ) from ISO high, medium, and low tests.  Champion, Wyatt M., et al. “Cookstove Emissions and Performance Evaluation Using a New ISO Protocol and Comparison of Results with Previous Test Protocols.” Environmental Science & Technology, 2021, 55, (22), 15333-15342. DOI: 10.1021/acs.est.1c03390 Lab testing can quickly compare emissions from stoves. […]

Clean Burning with Metering and Mixing

Primary air usually controls the rate of reactions: How fast the solid biomass changes into wood gas. Jets of primary air into the charcoal beneath the biomass add mixing while raising temperatures. Secondary air jets into the side of the flame can also supply needed mixing but tend to lower temperatures. Metering the gas supply […]


Pot Skirts – basic theory

Dr. Sam Baldwin describes the use of a pot skirt in his book “Biomass Stoves: Engineering Design, Development, and Dissemination (1987).” Changes in the length and diameter of the channel gap (between the pot and the interior of the skirt) result in dramatic changes in heat transfer efficiency. “In fact, the channel efficiency, defined as […]

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Aprovecho Announced as a Winner of the Wood Heater Design Challenge

The U.S. Department of Energy (DOE) Bioenergy Technologies Office (BETO), in collaboration with Brookhaven National Laboratory (BNL), Lawrence Berkeley National Laboratory (LBNL), and the Alliance for Green Heat, today announced the winning teams for the Wood Heater Design Challenge (WHDC).  Aprovecho Research Center, from Cottage Grove, Oregon, came in second place and won $25,000 with a novel burn pot, airflow configuration, and sensor package for pellet heaters. […]

Biochar Goals

A few years ago, on another series of hot summer days, Aprovecho hosted a seminar on biochar. About twenty enthusiasts from all over the US joined us for a biochar summer camp, lighting a lot of stoves and scaring the safety advisors. We needed more spark screens. At the closing event, we created a list […]