From void into vision, from vision to mind, from mind into speech, from speech to the tribe, from the tribe into din.

Monday, August 06, 2012

Solar Stove Design Challenge

Solar Cookers International needs new designs for a more durable solar cooker.  For years, people in refugee camps have been using the CooKit, a cardboard and aluminum foil solar reflector with a plastic bag as a "greenhouse" around a blackened pot, to cook food and reduce the need for cooking fuel and the consequent necessity for women and children to leave the relative safety of the camps to look for fuel, exposing themselves to injury, rape, and murder by the very people they've been trying to escape.  The Touloum camp in eastern Chad for refugees from Darfur is one place where these solar cookers have made a real impact.

The design criteria are
the reflector must be waterproof and UV resistant, cost less than US $25 and last for at least five years;
it must hold one or more three to five liter cooking pots;
the greenhouse replacement for the plastic bag should last for at least one but preferable two years or longer;
the reflector and greenhouse must allow the cooking pot to reach temperatures between 250 F/121C and 300F/149C;
both the reflector and the greenhouse must be lightweight, unbreakable and fold flat for shipping;
both must be easy to open and close, easy to clean and easy to store indoors;
the cost of the greenhouse should not exceed $10

Please spread the word as there are 10 million displaced persons and refugees in the world today, many in desert regions where solar cooking could be used, and more than 2 billion people are still cooking every day over open fires.  If solar cookers can reduce a portion of the need for combustible fuels and the resulting black carbon, it would be a great help to the people using them and help reduce local deforestation and climate change almost immediately.

More information at

You can support solar cookers in African refugee camps today through

One of my favorite solar oven designs was Dr Charles Greeley Abbott's from the early 20th century.  It was a parabolic trough that heated oil as its working fluid.  He built it on Mount Palomar in CA when that area was remote and used a clock and counterweight system to track the sun during the day.  The oven got hot enough to bake bread:

David Gordon Wilson of MIT has been working on another stored heat solar oven using a Fresnel lens to concentrate sunlight on lithium nitrate which can store heat up to 25 hours and produce temperatures of 450ยบ F over that period of time.  They say they'll have a production model available soon.

A few days ago, I remarked to a friend that the annual local solar cooker picnic, usually around summer solstice, hadn't happened this year.  Then I got this notice:

12th Annual Solar Picnic

Saturday, July 28th
11:00 to 3:00 (Solar Noon will be 12:51 PM)
Somerville Community Growing Center, 22 Vinal Ave. Somerville, MA  (near Union Square)
See map:

12th Annual Solar Picnic at the Somerville Community Growing Center

Celebrate the sun and another year's growth in the garden. Come and join us for a solar picnic - no gas, wood or charcoal grills, just solar cookers using the energy of the sun!

This event is a simple, traditional pot-luck picnic. No fire, just solar ovens/cookers. We will have a few solar cookers and some space available for you to bring your own. If you want to learn how to build one or see how they work, this is your golden opportunity! For more information see:

There will also be other solar devices demonstrated (of course, feel free to bring your own) and a good chance to see old friends and meet new ones. A great place for a picnic, the Somerville Community Growing Center is an urban oasis that was designed and built by local residents and is maintained by volunteers.

It's a recipe for a fine midsummer's day: friends, fun, food and the sun! Relax, chat, learn and explore the gardens. And when the delicious aroma of solar-cooked cuisine fills the air, come to the table and feast!

Sponsors:   The Boston Area Solar Energy Association: (a chapter of NESEA).

Somerville Climate Action:

My Solar Christmas
Short Term Climate Forces:  Black Carbon, Methane, and Tropospheric Ozone
Solar as a Cottage Industry