Entries by Kim Still

A Culture of Daily Experimentation

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 results. And that can lead to new […]

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

The Gates funded Global Health Labs and ARC/SSM invented 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 efficiency and reducing time to boil. 30 pre-heated primary air jets shoot up into […]

Secondary Air Jets in Charcoal Stoves?

Charcoal stoves are batch loaded like TLUDs (top loaded up draft stoves), but they differ greatly in how air flow is used to encourage combustion. A charcoal stove has lots of primary air blowing up into the fuel. A TLUD uses a small amount of primary air to create a relatively constant amount of woodgas […]

Cooking With The Sun

  Last week we shared info about retained heat cooking. It’s frequently paired with solar cooking for feeding folks with no earth-generated fuel expenditure at all. But does it work? The cooks at ARC think that it’s great  – in the summer time when we have lots of sunlight. Our preferred solar oven was invented […]

Retained Heat Cooking

While at ARC we focus on how to cook most efficiently with biomass, it is good to remember that some cooking can continue without consuming fuel. A retained heat cooker (RHC), also known as a Haybox, is a great way to save on fuel for appropriate cooking tasks such as simmering rice or beans. How […]

0.75 Constant Cross Sectional Area: A Winiarski “Rule of Thumb”

The Uganda 2-pot stove that is described on page 26 in the EPA publication “Test Results of Cook Stove Performance” is a natural draft stove that also uses much less fuel to cook and protects health. The document can be found at: https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100EKU6.TXT.  Has it been a while since you looked at this book, a comparison […]

Woodgas

Dr. Tom Reed frequently talked about selling a billion clean burning woodgas stoves. Now that the Biden administration is pointing out that natural gas (and electricity made from fossil fuels) are things of the past, it can be imagined that using woodgas to cook may become a larger part of a post-fossil-fuel future. “On January […]

Metering, Mixing, Temperature, Time

Here are lessons learned that summarize what we consider to be the ‘state of the art’ in 2021. Please remember that, as scientists, we do not consider these hypotheses to be true. The concepts are evolving and, like all knowledge, will coalesce into a state of greater accuracy as experience, experiment, and analysis shapes understanding. […]

Primary Air Jets

The blacksmith’s forge is probably the most familiar technology that blows jets of primary air up into charcoal or coal, resulting in the high temperatures needed to shape or melt metals. A forge needs air at high pressure (10” water column) to do its work. A fan (usually a radial pressure blower) capable of moving […]