What’s Cooking at Aprovecho

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Capacity Building with CSIR

Over the past 3 years, thanks to three grants from Fire Capital, Aprovecho has been working with CSIR (Council for Scientific and Industrial Research) in Ghana to expand their lab capacity. We have focused on teaching stove design principles through co-developing a stove retrofit for boarding schools in Ghana.

During the recent in-person workshop, Jaden visited the lab to help with the building of the prototype and plan for its installation at a local school. This prototype will go over an existing stove at the school, increasing thermal efficiency and reducing indoor emissions. With user, manufacturer, and lab result feedback, CSIR will finalize their design and give stoves to ten schools for a larger impact study. 

CSIR employees working on the new stove prototype

The LEMS in Bangladesh

Sam went to Bangladesh to update their lab and provide training. The Bangladesh University of Engineering Technology in Dhaka now has a lab that can test cookstoves according to ISO 19867 standards. This provides a useful development tool for the area as well as way to teach the next generation about cookstove development. Sam observed that while urban and peri-urban areas had access to gas and electricity, households couldn’t always afford it, highlighting the need for clean biomass stoves even in areas with access to alternative fuels. 

Sam also visited Life Green Energy, a stove manufacturer focused on forced draft stoves. Together, they developed a local Jet-Flame prototype aimed at saving fuel and reducing emissions. The prototype was able to burn green wood while other brick stoves could not. More development is planned to improve the product.

Sam Bentson testing at the lab in Bangladesh

Baseline Efficiency Paper Published

We were recently published in Environmental Science & Technology for our paper on the baseline thermal efficiency of wood and charcoal stoves: Quantifying the Efficiency and Fuel Consumption of Cooking with
Traditional Wood and Charcoal Stoves in Malawi, Ghana, and Kenya.

Aprovecho and Oregon State University paired with SunFire (Malawi), KIRDI (Kenya), and CSIR (Ghana) to conduct a total of 720 thermal efficiency tests on traditional wood and charcoal stoves. The goal was to compare the baseline efficiency of stoves with UNFCCC (United Nations Framework Convention on Climate Change) default efficiency, which had recently changed.

We developed a new test protocol, the UCET (Uncontrolled Cooking Efficiency Test), which measures thermal efficiency on any meal cooked. We found that the average thermal efficiency was between the new and old UNFCCC defaults. It was also found that firepower, pot/pan size, and cooking method are strongly correlated with efficiency. 

Women cooking during a UCET
Emission testing equipment set up at an Oregon home

What’s Cooking at Aprovecho

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The LEMS in Ethiopia

Jaden and the trainees in the Ethiopia lab

In March, Jaden traveled to Ethiopia to assist in the installation of the LEMS and train lab technicians on ISO testing for cookstoves.

15 trainees from all over the country attended the training. The LEMS was procured by SNV and their sponsors and was given to Ethiopia’s Department of Water and Rural Energy at the end of the training and installation.

The installation of LEMS in different countries is vital in creating clean cooking solutions that can be used throughout the world. We hope to continue working with the lab in Ethiopia to design new stoves.

Proyecto Mirador in the Lab

Proyecto Mirador testing their stove in their lab in Honduras

Proyecto Mirador has been working on improving the efficiency of their Dos por Tres stove. After successful tests in their lab, they traveled to Aprovecho from Honduras to confirm their results.

They got the same results in both labs, showing how effective iterative design testing with the LEMS can be. Now they can install stoves that use less fuel and cook things faster in Honduras and Guatemala.

Field Testing Results Published

Emission testing equipment set up at an Oregon home

In 2023, we measured the emissions from cordwood heaters in Oregon. There are very few studies that evaluate emission measurements in the field for wood heaters. As seen from our experience in cooking stoves, emissions in the field are often higher than lab tests, and field studies help us understand how people use their stoves so we can make better designs.

We’ve been using the data we collected to create lab tests that reflect user behavior and design clean and efficient heating stoves that meet user specifications.

The resulting paper, In-situ Measurements of Emissions and Fuel Loading of Non-catalytic Cordwood Stoves in Rural Oregon, was recently published in the Journal of the Air & Waste Management Association.

Market Driven Stoves

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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?

New on the Website! Improving Biomass Stoves, 2025

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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!