Entries by Kim Still

Tuning A Stove With Real Time Data

PM2.5, CO2, CO and other metrics measured by the LEMS are displayed in a real-time graph during testing. When enough data is available in real time, it is not hard to make progress improving a stove. The LEMS emission hood provides real time, holistic feedback as the experimenter makes changes. Watching all of the measures […]


Dr. Kirk Smith and The Breathing Space Project

Dr. Kirk Smith, a hero ARC worked closely with Dr. Kirk Smith (1947-2020) when we helped to include emissions in the Water Boiling Test, used to evaluate biomass cookstove performance, for the Shell Foundation. We included the first “Tiers of Performance” with a simple approach that divided stoves into two categories: improved and unimproved. It […]

Post Combustion Reduction of PM2.5

Electrostatic Precipitation: Smoke particles are negatively charged and attracted to positively charged metal plates that are automatically cleaned. Both automobiles and the biomass industry rely on improving combustion efficiency and post combustion reduction of PM2.5 to achieve “clean burning.” It’s really hard to rely on the combustion chamber to burn up enough of the harmful […]

Mass, Insulation and Thermal Efficiency

Kuniokoa Stove, original top replaced with cast iron top. It is more likely that close to 50% thermal efficiency will be achieved with a biomass burning stove when: Small sticks are burned that produce tall, hot flames while using the least amount of wood.A 30cm in diameter aluminum pot is used with a 14cm high […]


Justa, Dos por Tres, Patsari Stoves!

Dos por Tres Stove with Chimney, photo courtesy of Proyecto Mirador During an ETHOS panel discussion on Cooking, Health, and Climate, it was great to see that the Justa stove with chimney protected health so well. Chimneys are mandated by law in the USA/Europe/China and many other countries. When Mahatma Gandhi returned to India from […]


ETHOS is Great!

Yesterday morning I was on an ETHOS panel discussing stoves, health and climate change. I loved the discussion and was filled with hope that facing the end of the fossil fuel era might catalyze better use of resources.  Living sustainably has been a dream of mine since I was 15 years old in 1967. Like […]

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Temperature, CO & PM 2.5

High temperatures in the combustion chamber seem to have both positive and negative effects on emission rates of biomass. Higher temperatures lower the residence time needed for more complete combustion. At the same time, especially with dry wood, the rate of reactions (how much wood gas is being made per unit of time) is increased. […]

One Acre Energy Comparisons

One of my favorite reference books is “The Energy Primer” published in 1974. It has comprehensive review articles on solar, wind, water, and biomass energy. The following chart comes from a great article on biomass written by Richard Merrill. When I taught semester courses to college students at ARC, I tried to give students useful […]

Natural Draft Top Lit Up Draft Stoves, 2021

Dr. Tom Reed, Dr. Alexis Belonio, Dr. Paul Anderson and Kirk Harris have refined TLUD technology A natural draft TLUD can be as clean burning as a forced draft TLUD burning wood pellets. On the other hand, a natural draft Rocket stove needs a fan to be clean burning. Dr. Tom Reed’s forced draft (FD) […]