Entries by Kim Still

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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) […]

Appropriate Technology as Craft

A St. Ayles skiff, my favorite boat Before I met Dr. Larry Winiarski I was a boat builder, but I had already realized that my love for making boats was mostly supported by rich people. And when my friends and I built a 36’ ocean going sailboat it was great but after several years of […]

Back to Basics – Fire, part 2

In our Nov. 24 newsletter, we shared a basic description of how wood burns from Samuel Baldwin’s book “Biomass Stoves: Engineering Design, Development, and Dissemination” (1987). Here are more details about the process from the same book: “The temperature of the hot gas above the wood is typically around 1100ºC and is limited by radiant […]

Introducing Aprovecho’s New Executive Director, Dr. Nordica MacCarty 

Photo: Karl Maasdam/OSU Foundation Aprovecho Research Center is pleased to announce that Dr. Nordica MacCarty has accepted the role of Executive Director. Dr. MacCarty takes over the position from Dean Still, who continues on as Research Director. Dr. MacCarty is also an Associate Professor of Mechanical Engineering at Oregon State University where she will continue teaching […]

Back to basics – FIRE!

Sometimes it’s good to step back and review the very basis of stove work – fire. Samuel Baldwin gives a good description of how wood burns in his book “Biomass Stoves: Engineering Design, Development, and Dissemination” (1987). “The combustion of wood and other raw biomass is very complicated but can be broken down crudely into […]


A Culture of Daily Experimentation

Testing a Chitetezo Stove with a Jet-Flame What do I like most about Aprovecho Research Center? We have created a “culture of daily experimentation.” Scheduling two to three experiments every morning means that we can try less-likely-to-succeed variations. That’s great because experiments that don’t succeed in improving a stove often reveal interesting and possibly unexpected […]

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Video: Lighting a Fire With The Jet-Flame – No Smoke

The Gates funded Global Health Labs and ARC/SSM invented the Jet-Flame Global Health Labs, Shengzhou Stove Manufacturer and Aprovecho teams show off the Jet-Flame Shengzhou Stove Manufacturer manufactures the Jet-Flame (jet- flame.com) that is being field tested in over 30 locations. Our lab helped to create this accessory that is designed to reduce emissions while increasing thermal […]