Climate Action Myanmar Project #16100

Improved Cook Stoves for Burma

by Solar Roots

Project Report | Apr 6, 2015
The Four Brick Stove

By Bruce Gardiner | Project Director

The clay/straw bricks straight out the moulds

For the last two years, I have been working on developing a stove based on a design I got from my good friends, Jon and Flip Anderson of Corvalis, Oregon. At first, we called it the Four Brick Stove, but as time has gone on, I have expanded it to what is now a Six Brick Stove. Jon and Flip have been building stoves like this for years in Haiti and Timor L'Este and I first experimented with it in Haiti in 2013. One of the great benefits of such a design, is that it can be made out of several different materials. Usually Jon and Flip use clay, mixed 50/50 by volume, with insulating material such as straw or sawdust and this is how I started in Haiti and Burma. However I was not fully satisfied with the results, due to poor quality clay, and as it turns out, my lack of understanding how to work the clay, to get the best out of it.

Later, I began experimenting with a mixture of cement and rice husk ash, which makes very neat bricks. One of the great advantages of this material is that the bricks can be made only 1.5" thick, providing great savings in the cement component, which is relatively expensive and requires much energy in its production. One of the great design features of the 4-brick stove is that the bricks are "keyed" to stay upright, and not collapse in on themselves. Another important feature is that the bricks can be scaled up to almost any size. This is particularly useful when it comes to making a powerful stove for instutional use, like the one we put inside a 55 gallon drum.

My goal is to learn how to make the bricks out of high quality clay and rice husk ash and to fire them properly to withstand the heat of daily cooking. In this, I hope to work with potters that I have recently met in Burma. They have the experience with the local clay and in particular, the heat-resisting clay called kaolin. So, I have many more experiments ahead of me. If you like our work and would like to support it, please consider making a donation. Thank you!

Assembling stove in Burma, now with a 5th brick

Stove now with 6th brick, adapted for 55gal drum

The clean lines of the cement/rice husk ash stove

The glow of clean burning sticks in a large stove

A large stove in action in Naung Taung monastery

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Jan 6, 2015
Stove Factory in the Delta

By Bruce Gardiner | Project Director

The rice-husk burning kiln

During my trip to the Mangrove Services Network (MSN) in the Delta region of Bogale, I had the great fortune to visit a small stove factory that they had helped establish. The mangrove forest, which used to grow extensively on the shores of the Ayerwaddy River Delta has been decimated in recent years by people establishing shrimp farms and cutting the trees for conversion into charcoal. I was shocked to learn that shrimp farms only have a limited productive life and are often abandoned after only 5 or 6 years. Of course, once removed, the mangroves take decades to re-establish themselves by natural regeneration, if they ever do. The loss of the mangrove forest was a significant contributing factor intensifying the extensive destruction and loss of life caused by Cyclone Nargis in 2008. To counteract this, the work of the Mangrove Services Network has two main thrusts. The first is to identify the strongest mangrove species that will re-establish quickly and permanently and help the local people to plant these trees in their community. The second thrust is to help local inhabitants develop alternative sources of livelihood, so they are not forced to cut the mangroves for income.

One of these MSN livelihood projects was a stove building factory using a kiln that burns rice husks as fuel. Rice husks are a low value by-product of rice growing in the Delta and are freely available everywhere. Without a good draft of air, they tend to smolder and produce a great deal of smoke. However, MSN overcame this drawback by using a 30ft high chimney which creates a huge draft that helps the husks burn cleaner. They have a damper in the system that allows them to control the burn and thus, the temperature of the firing. A wonderful by-product of this process is the ash that is left when the burning is complete. Rice husk ash is high in silica content and when added to the clay mix, it gives the stoves added insulation and resistance to heat. For me, this a win-win situation: a waste product from agriculture is being used productively, then the by product from its combustion is helping the stoves perform better and last longer.

But there is still room for improvement. In the future, I hope to work with MSN to improve the design of their stoves. At the moment, they are using a knock-off version of the Thai bucket design. While cheap to produce, it is not a very efficient or clean burning design. On my next visit to Bogale I hope to help the stove builders learn about the principles of the Rocket Stove and develop with them a design that will fit their production facilities and be popular in the local market. Please help Solar Roots and the people of the Ayerwaddy Delta to preserve the mangrove forest and to improve the lives of the local inhabitants. Your support is greatly appreciated.

Forming the stoves using a spinning mold

Worker holding the mold, with wet stoves

Project Director with burned rice husks behind

Mixing and extruding the clay

A special stove for burning sawdust or rice husks

Links:

Description of Cyclone Nargis in 2008

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Oct 7, 2014
The Stainless Steel Institutional Stove

By Bruce Gardiner | Project Director

Looking at the combustion chamber inside the drum

The Institutional Stove

There are many institutions in Burma that cook food in large quantities, such as schools, orphanages and monasteries. In Naung Taung monastery, (see last report), it is normal for 1,000 people to sit down for lunch! I had conducted a successful stove training there earlier and I was determined to build a scientifically designed Rocket stove to replace the existing inefficient and smoky fires.

After several disappointing trials with insulated clay bricks, I determined to use a more durable material for the combustion chamber of our institutional-sized stove. I chose stainless steel, as it resists the effects of heat much longer than mild steel. Although stainless steel is imported from China and it is relatively expensive in the Burmese context, I wanted to see how it would perform.

With some other stoves I had built in the past, cooks complained that there was not enough heat, so this time I decided to use a combustion chamber that was 8” by 8” square – a real giant! I was ably assisted in the building phase by Hamish Lee, our New Zealand volunteer, who had a engineering background and good construction skills.

Stainless steel is a very hard metal, difficult to drill through, but with the new spot welder I had recently brought from the US, making the required joints was no problem. For stability and to hold the insulation around the combustion chamber, I placed it inside a 55 gallon drum. This is similar to the design used by Instove, a non-profit stove builder based in Oregon.

Inside the drum and surrounding the combustion chamber I placed wood ash collected from previous fires, which insulates the chamber and slows down the heat loss to the outside.

After 2 days hard work, Hamish and I had the stove ready for testing. With a ten foot high chimney, also 8” x 8”, creating a mighty draft, the stove burned extremely hot and produced almost no smoke after start up. Everyone was impressed!

Later, with two other volunteers from the US, the stove was installed in the kitchen of St Mathews Orphanage Center, where it is being used on a daily basis. I am very curious to see how the stainless steel holds up to the intense heat and what the cooks have to say about the convenience and performance of their new institutional stove.

Hamish spot-welding the chamber to the drum

Wood feed on the left and chimney on the right

Hamish and helper customize the grate

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