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Solar Oven Cookers

Solar cooking- Sun Power Saves Lives & Saves Trees

A solar cooker in use by Gambian Women. Visit Solar Cooking Review for more amazing Solar oven designs. Also check out The Basics of  Solar Cooking at Cooking Schools. Net

Evolve to Ecology will be conducting solar oven and water filter workshops in Central America and Haiti.

Research has found that 36% of the world's fuelwood needs (or 350 million tonnes of wood per year, according to UNICEF) could be replaced by solar box cookers, saving 500 kg of wood per family per year, equalling millions of trees.

Half the inhabitants of Earth cook over woodfires. Nearly half the world's wood supply is used as fuel. But there's not enough of it to go round -- more than 2 billion people now face shortages of fuelwood.

Forests in the developing countries are shrinking by more than 15 million hectares a year. The critical forest-to-people ratio has never been lower -- worldwide, it is now less than half what it was in 1960.

Meanwhile, deforestation leads to soil erosion, floods and climate change, severe environmental degradation, and increasing poverty and hunger.

It's a complex problem, like all environmental problems. But there's one simple answer, that can save millions of trees, provide clean, safe drinking water, doesn't smoke, and costs very little -- solar box cookers, which can be made from cardboard cartons.

 Cookit Panel Measurements

The information on this page is thanks to "Journey to Forever" and the "Solar Cooking Archive"

" Journey to Forever is a pioneering expedition by a small, mobile NGO (Non-Government Organization) involved in environment and rural development work, starting from Hong Kong and travelling 40,000 kilometres through 26 countries in Asia and Africa to Cape Town, South Africa".

Solar box cookers would also save millions of women many hours (or days) wasted searching for firewood, giving them the time to look after their children, grow more food, and for education -- which is the key to reducing population growth.

-- "On the first day, the women walk to the nearest place where wood can be gathered. On the second day, they search for firewood. The third day is spent carrying the wood on their backs home to the village." -- from Chad, Africa

Solar box cookers are easy to make -- one cooker designed to be simple enough for 10-year-olds to build without tools in less than an hour is now helping to feed refugees in Africa.

Solar box cookers cannot replace firewood use, just supplement it. Other possible supplements for rural use are biofuels, biogas, wind and water power.

There is no feasible replacement for firewood in much of the world, nor is one required -- what is required is to balance growing demand with dwindling supplies.

Unlike fossil fuels, firewood is a renewable fuel, it's locally available, it supports local employment, and when properly burnt it doesn't contribute to the greenhouse effect -- the CO2 it releases is simply recycled.

But too often it isn't properly burnt: cooking fires are often inefficient, wasting energy, failing to combust the wood properly, contributing to greenhouse gas release and creating severe indoor smoke pollution.

Half the 3 billion people who use firewood don't have proper stoves or chimneys. Research and development efforts all over the world are working to remedy this problem.

More and better woodstoves mean less waste, more trees, better health and a better environment for all.

Second to firewood comes charcoal, which is an efficient, smokeless and clean fuel, but the charcoal production process is often inefficient and wasteful. Again, this is a focus of worthwhile development efforts in many countries.

At the root of all these problems, and of all development problems, is the grim spectre of poverty, now growing faster than ever before -- faster than the forests are shrinking, faster than the deserts are spreading -- and the cause of it is an unjust and inequitable economic system.

Clean, safe water

The WHO says diseases spread through contaminated water cause 80% of the world's illnesses. Solar box cookers can pasteurize drinking water: heating water to 65 deg C for six minutes destroys disease organisms, and this temperature is easily achieved with solar box cookers.

"UNICEF estimates that 60% of rural families and 23% of urban families in developing countries are without safe water ... The most common recommendation is to boil the water. This recommendation is seldom followed [because of] the amount of scarce fuel it would require." -- From "A summary of water pasteurization techniques" by Dale Andreatta

"Recent Advances in Solar Water Pasteurization" by Dr. Robert Metcalf. "During the cholera outbreak in Peru, the Ministry of Health urged all residents to boil drinking water for 10 minutes. The cost of doing this would amount to 29% of the average poor household income," writes Dr Metcalf. "As a microbiologist, I have always been perplexed as to why boiling is recommended, when this is heat far in excess of that which is necessary to kill infectious microbes in water."

Solar Water Pasteurization -- Techniques, resources, discussion at The Solar Cooking Archive

How to make solar box cookers

Plans and pictures of many different types of solar cookers:

Construction plans for Roger Bernard's improved "Cookit" Foldable Family Panel -- as used at the Kakuma refugee project in Kenya.

The "Minimum" Solar Box Cooker: a powerful solar oven you can build from two cardboard boxes in a few hours.

The "Easy Lid" Cooker: designs for box cookers have grown simpler, but fitting a lid can still be difficult and time consuming. In this version, a lid is formed automatically from the outer box.

"Principles of Solar Cooker Design" by Mark Aalfs of Solar Cookers International (in two parts) -- summarizes the basic principles used in the design of solar box cookers. Heat Principles, Materials Requirements, Design and Proportion, Solar Box Cooker Operation, Cultural Factors.

Designing and building home made focusing solar cookers by Hannu Virtanen -- a complete guide to making parabolic cookers using locally available materials.

"You can cook almost anything with the sun and a 'low tech' box cooker that you can build yourself," says low-tech guru Doug Edwards. "On this day the oven reached 250 F within 35 minutes. Here in California, where I live, I have cooked a beef roast on the shortest day of the year where the outside air temp was 40F." Solar cookers, plans, recipes and more.

Links to solar cooking resources and other good low-tech stuff.

Parabola Design Wood Model -- a simple wood model is used as a tool to assure the exact parabolic shape of the mirror. Precision is very important to get a small focal sun-spot and a high cooking temperature. Details a very simple drawing tool to design a parabola, makes any parabolic curve with ease. You need two pieces of straight wood, a stiff string and a pin to make this tool and to be able to draw any parabola for a desired focal distance and size.

The AMSI Solar Cooker Project

A Tracking Solar Concentrator for the home experimenter
-- Teton Engineering Inc in the US developed a 20,000 Btu (6000 watt) solar concentrator designed specifically for the backyard mechanic to build using simple construction and basic materials. Full-text online manual -- note the disclaimers and safety warnings: "Working with solar concentrators is VERY DANGEROUS."

Other solar oven  resources

Haybox cooking: What is a haybox? Simply an insulated box used for slow cooking. Put the food in a pot and heat it up, put the pot in the haybox and it stays hot for a long time, cooking slowly. Haybox cooking saves energy. Hayboxes and solar box cookers go very well together.

Haybox Cookery -- Sunseed Tanzania Trust

How to Use a Haybasket

Some recipes suitable for a haybox

Rediscover the hay-box cooker -- A non-electric version of the modern Crock-Pot. Instructions for building the box and preparing food items including cooked cereals, pot roasts, vegetable beef stew, boiled dinners and baked beans.

Haybox how to and description -- Lost Valley Center

ClearDome SolaReflex diffused foil, and AA flat, bendable mirror surface sunlight reflector panels (previously known as SolarFlex) -- achieves the highest known level of radiant solar reflection: 97.4%! From ClearDome Solar:

Solar Cookers International's Solar Cooking Archive

The most comprehensive resource on solar box cookers: general information, news, plans, undefinedsolar cooking documents in English, German, Spanish, French, Italian and Portuguese and Arabic, country reports, technical reports, newsletters, the Solar Cooker Review, multimedia, photo gallery, slideshow, international directory, NGOs, manufacturers, supplies, books, mailing list discussion (with searchable archives), comprehensive list of links to other resources.
FAQ -- solar cooking in a nutshell:

Solar cooking documents :

Search the Solar Cooking Archive:

Join the solarcooking-L Mailing List:

Searchable yahoo mailing-list archives:

Solar Cooker Review, published two or three times a year.

"The big adventure of a little solar cooker"

-- Roger Bernard tells how designing a cooker simple enough for 10-year-old schoolchildren to build in less than an hour led to the development of a simple solar cooker for poor rural people. The "Cookit" Foldable Family Panel cooker is neither a "solar oven" nor "curved concentrator" but a simple yet powerful hybrid. Full plans and instructions

How the "Cookit" is helping refugees in Kenya

Solar cooker in Nepal: cost $3
"Understanding Solar Cookers and Ovens" by Thomas Bowman, Understanding Technology Series, Technical Paper # 36, Volunteers in Technical Assistance (VITA), 1985 -- Useful overview of the pros and cons of the different types of solar cookers available, from Professor Bowman, Head of the Mechanical Engineering Department at the Florida Institute of Technology, and a VITA volunteer. He points out that, though solar cookers were often resisted by traditional communites in the past, simply because they weren't used to them, these days they often don't have much choice in the matter because the supplies of traditional fuel have run out.

"Solar Cooker Construction Manual" -- 5,000-word illustrated booklet, prepared by VITA Volunteers, 1967

"Understanding Solar Concentrators
" -- VITA Technical Paper # 30, 1985, 7,000-word illustrated booklet.

In "Reduction of tropical deforestation by massive use of solar cookers" Ari Lampinen of Technology for Life, Finland, explains why the world needs 200 million solar box cookers.

Review of solar cooker designs by Ashok Kundapur: 56 major designs, 59 variations and 66 drawings of solar cookers. Test data by other researchers, a new set of parameters for testing solar cookers, reflectors, and insulating material.

It's made of baskets!
Nepal's Centre for Rural Technology (CRT) is an autonomous private sector, professional development organization established in August 1989, engaged in developing and promoting effective technologies to meet the basic needs of rural people.

"Breakthrough in Kenyan Refugee Camps" reports on Solar Cookers International's work in Kenya. "More than 5,000 families have attended workshops and returned home with their own solar cooker. It costs only US$10 to supply each of these families with a solar cooker, a black pot, a supply of trial food, and instruction on how to use their new cooker. Follow-up visits have revealed a high level of use."

"Solar Cookers and Social Classes in Southern Africa" by William Noble Grundy -- interesting examination of the failure of a solar box cooker project in Lesotho, Southern Africa: "Several projects have already targeted the people who need solar box cookers the most, the rural women. Those projects have failed for complex reasons involving the resistance of traditional cultures to invasion by foreign innovation."

"Cooking with the sun: Chilean village's experiment with solar ovens offers alternative to widespread deforestation", San Francisco Chronicle, July 26, 2001 -- Lucila Rojas remembers the days when she and her neighbors risked their lives to cook a hot meal over a wood-burning stove. "We had to steal firewood, because there was no longer any left in the places where you could freely look," she said. "Sometimes we were chased (by landowners), even by gunshots. I was fed up. I didn't want any more war." Now she has a solar oven in her home.

Books on Solar Cooking

"Heaven's Flame, A Guide to Solar Cookers" by Joseph Radabaugh, 144 pages, Home Power, 1991.
Complete instructions on how to build the high-performance cardboard SunStar solar cooker, discussion of other solar cooker designs, question and answer section, how solar cookers are being accepted and used around the world, detailed cooking instructions.

"Cooking with the Sun: How to Build and Use Solar Cookers" by Beth & Dan Halacy, 115 pages, Morning Sun Press, 1992.
Detailed plans for building a plywood multi-reflector box cooker, a cardboard single-reflector box cooker, a cardboard parabolic cooker, and a solar reflector "hot plate" cooker, with line drawings and photos, history of solar cookers, solar cooking tips and necessary cookware, 62 pages of solar recipes.

"The Expanding World of Solar Box Cookers" by Barbara Kerr, 1991.
The history and theory behind solar cooking, by one of the developers of the simple but effective cardboard solar box cooker. "Unaware that it 'should' be made of metal or wood, I used cardboard boxes and thus opened a new line of solar box cooker development" (March 1976). With plans and instructions for building and using a solar box cooker. Online version at Solar Cooking International.

For a printed copy, with photos and diagrams, send $15 to Kerr-Cole Solar Box Cookers, PO Box 576, Taylor, AZ 85939, USA, email

"Making the Most of Sunshine –- a Handbook of Solar Energy for the Common Man", by S. Narayanaswamy, Vikas, New Delhi.
The author's passion for solar energy grew out of his career as a top administrator in Kerala state in India. It includes hundreds of interesting tidbits on every form of renewable energy, but two-thirds of the book deals with solar cooking. More than a dozen different solar cooker designs, along with practical sections on the best day-to-day uses of any solar cooker. The final chapter, "Promotion of Solar Cookers," is essential reading for anyone introducing solar hardware, especially in developing countries.

Solar Recipes -- Based on an original solar coobook produced by the Sacramento Municipal Utility District 10 years ago. Introduction, Cooking Guidelines, Beverages, Bread, Casseroles, Desserts, Eggs & Cheese, Meat Dishes, Pasta, Poultry, Snacks, Vegetables. Full-text online:

Schools solar

"Sunlight Works -- Solar Science Educational Activities for Children" by Heather Gurley and Bob Larson.
Large-format, well-illustrated, 32-page book aimed at using solar cooking as a learning activity for children ages 8 to 12. Variety of activities illustrating solar concepts, including plans for building a solar box cooker. From: SunLightWorks, Inc., 2255 H Shelby Drive, Sedona, Arizona 86339, USA, email:

-- "We are living and participating in a very strange system. Humanity has one foot stepping towards the stars, while the other is mired in a sinking sea of poverty. The distance between humanity's two feet is growing. We can help reverse the process by teaching several billion people in the Third World how to build and use solar box cookers." -- From "Balancing the Scales" by Bill Sperber

No fire, no smoke

Solar box cookers produce no smoke and no pollution: woodsmoke from cooking fires causes respiratory infections which kill at least 5 million young children each year.

Indoor smoke pollution now ranks 8th in health burden worldwide (lost years of healthy life), and ranks fourth in the "least-developed" countries (which make up about 40% of the world population) according to the World Health Organization's World Health Report 2002.

"Smoke gets in their eyes" -- Independent research indicates that indoor air pollution is a contributory cause of around two million deaths in developing countries. Acute respiratory infections, ear and eye problems, breathlessness, chest pains, headaches and giddiness are just some of the symptoms that poor woman and children suffer in their rural homes. And the cause? Smoke from cooking. ITDG -- Intermediate Technology Development Group.

Full 60 page report: "Reducing indoor air pollution in rural households in Kenya: working with communities to find solutions", ITDG project 1998-2001, January 2002. Acrobat file, 3.4Mb

Study from Berkeley: Rural areas of Kenya like in all Sub- Sahara Africa is almost wholly dependent on biomass as the primary source of energy for its bulk of people. The biomass is also often obtained green and then seasoned for use mainly by women.

The information on this page is thanks to "Journey to Forever" and the "Solar Cooking Archive" Also check out The Basics of  Solar Cooking at Cooking Schools. Net


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