Market Driven Stoves

Photo by Güldem Üstün on Flickr

One of the biggest mistakes I have made was thinking that I could predict what stove would sell in a market. If only I had always followed Sam Baldwin’s advice and done market testing before manufacturing! In Southern India, as part of the 2003-6 Shell Foundation project, we had outspoken distributors who yelled in meetings that a successful stove had to cost $5, that 5,000 had to fit on a truck, and that it had to be designed by cooks! The stove had to be short so food could be stirred and work well at the low firepower required by villagers around Chennai, toast a chapatti, etc., etc.

When the carbon market crashes, affordable stoves continue to be sold and used. When stoves are purchased the consumer is convinced of their utility. The trick is to try to bring best solutions into marketable products but, luckily, engineers love a challenge!

A pot skirt, SuperPot, constant cross sectional stove top, stick support, keeping a fire hot, can all significantly increase heat transfer efficiency. Even Jet-Flames can be made for around $5. TLUDs can be inexpensive. There are many techniques to improve the market driven stove! 

Check out the new Osprey funded book Improving Biomass Stoves, 2025  for examples?

Fireless Cooking Has A Long History

Thanks to Robert Fairchild for sending this reminder that what we call a “Haybox” cooker has a lot of history behind it!

Of course fireless cooking methods have been used since ancient times, but fireless cookers began to be introduced to U.S. in the mid 1800s, becoming commercially manufactured and quite popular in the US in the early 20th century. The Haybox, or “retained heat cooker,” works by placing a boiling pot of food into a well insulated box that keeps the heat in the pot, generally producing thoroughly cooked food in a couple of hours without further interventions from the cook.

Retained heat cooking can save 20%-80% of fuel for cooking, depending on the food and amount cooked. This method is not safe for every kind of food, but Aprovecho cooks especially love it for a big pot of beans or rice. The fire and the pot don’t need to be tended after boiling, and the food never burns!

If you are interested in making one for your own use, here is the ARC Rule of Thumb Design Principles for a Haybox.

You can find an excellent, well illustrated history of the Fireless Cooker, from early versions through its modern re-emergence in low-income countries, at the USDA National Agricultural Library: The Fireless Cooker (Emily Marsh, Ph.D, MLS)

Remembering Ken Goyer

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On the front porch of the house he built in West Eugene, Ken Goyer shows an example of the Six Brick Rocket Stove

Photo by Paul Neevel for the Eugene Weekly

I think about Ken making the lightweight, insulated bricks from Bailey Hill yellow clay for the Uganda submerged double pot stove in 2002. Exposing the sides as well as the bottom of the pot(s) to flame and hot gases increased fuel efficiency. The Rocket combustion chamber, also made from Ken’s recipe (clay and sawdust) was a 5” in diameter, 12″ high cylinder, placed under the first, larger pot. 

We tested the stove using one pound of wood. 6.6 pounds of water in the first pot (12″ diameter) boiled in ten minutes. We had a great week of sunny, windy weather and it was great fun to work with Ken and Peter Scott (Burn Stoves), who was about to go to South Africa. 

I met Ken when he was doing “Ken’s Ten-Buck Tune-Ups.” He first saw open cooking fires when he went to El Salvador in 1992 to help Sylvia Gregory with her women’s empowerment project. With funding from Rotary Club, Ken directed construction of brickmaking kilns for refugee camps near Lira in Uganda and Gulu in Darfur. He helped to start Aid Africa and is one of the inspirational people we miss and so fondly remember. He was one of Larry Winiarski’s best friends.

New on the Website! Improving Biomass Stoves, 2025

The new Osprey funded book is a compilation of fifty-one updated newsletters, reflecting the current state of knowledge at ARC. 

Stove experiments fail to improve prototypes as often as they succeed. One of the great things about iterative development (testing effects of single changes in prototypes under the emission hood) is that you learn as much from failures as from success! Every day moves us forward. 

How to achieve close to complete combustion and close to optimal heat transfer efficiency are describable in single page summaries. 

Aprovecho is helping to manufacture biomass cooking and heating stoves that are clean burning enough to protect urban air quality and meet the Paris Agreement. Most of the stoves that we help to make are not this clean burning, but how to achieve cleaner combustion is better understood and less expensive to achieve.

The hope is that these short summaries will be more accessible and more fun to read compared to previous longer-winded attempts at communication.

Our lab is open to visitors and we try to be good hosts. After years of trying, the coffee is becoming more palatable. 

Come on by!