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A 40' deep focus parabolic mirror generating 88KW worth of steam power


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Augustin Mouchot's Sun
Machine 1878 Unimversal
Exposition - Paris

Campus Center for Appropriate Technology                Page 2 of 5
How hot do solar cookers get?
This depends primarily on which type of cooker you are using and the size of cooker you build.
Parabolic cookers can reach extremely high temperatures. Therefore, they are quite capable of reaching average cooking temperatures of between 212o F (100oC) and 350oF (177oC) for frying, boiling and baking foods. Cooking time is affected by the size of the parabolic dish, the size of the cooking pot and outside temperatures.
Parabolic cookers can cook any type of food with a variety of different methods and have shorter heat up times than solar ovens. However, they can be inconvenient to use because of size, cost, risk of fires, and glare.
Typically box ovens can reach temperatures of 350°F (176°C). One advantage of cooking with a solar oven is that you can leave the food to cook without supervision: it is not always necessary to achieve high temperatures to cook food. Cooking at lower temperatures allows

the food to cook evenly and remain warm without burning or scorching.

Co = (5/9) (F - 32)
Fo = (9/5 · Co) + 32


"A small burning mirror typical of those used by natural scientists during the 1500's and 1600's."
~Butti & Perlin

The History of Solar Energy Use

The harnessing of solar energy began with the ancients. They were the first to begin using passive solar design in their homes and to use glass to trap solar heat. The use of curved mirrors to concentrate the sun's rays was developed by the Aztecs, Greeks, Romans, and Chinese. The concept of "burning mirrors," for weapons, has been considered for millennia. It was through the Greeks geometric development that they discovered a parabolic surface held the ideal shape for these burning devices.
Awareness of the ability for glass to trap solar heat became increasingly important in the eighteenth century. It was during this century that
the first "hot box" was invented by Horace de Saussure. With the advances in science and technology during the Industrial Revolution, came the development of various devices designed to harness solar energy. Solar pumps, solar cookers, solar heat engines, and solar stills are just some of the inventions of this time.
Augustin Mouchot, a professor of mathematics at the Lyceé de Tours, was an important figure in this revolution. He was the first to develop a solar cooker; he was successful in finding a benefactor to fund his research. This lead him to Africa where he invented a portable solar oven for the French troops.
Although these various solar inventions were never very successful on a large scale, they did aide in the advancement of a practical development of this revolutionary technology.
It was in the 1950's that solar cookers began to evolve into the products we see today. The United Nations and other agencies began solar cooker design studies. These studies found that when properly constructed, solar cookers not only cooked food thoroughly and nutritiously, but also were easy to build and use. Programs were created to introduce these designs to remote locations in the hope of aiding those in need.

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Archimedes 212 BC
Legendary Ancient Greek mathematician and engineer
is said to have used burning mirrors to defend a Greek Island at Syracuse from an invading Roman fleet


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       Roger Bacon  1278 AD
An English Franciscan monk
and first scientist to emerge from out of the dark ages        
Imprisoned as a heretic for advocating the use of parabolic mirrors


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Leonardo da Vinci 1515 AD
Depicted parabolic mirrors in his now famous criptic diagrams


Augustin Mochot,
Professor of Mathematics1860
"Eventually industry will no longer find in Europe the resources to satisfy its prodigious expansion…Coal will undoubtedly be used up. What will industry do then?"

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