The principle of harnessing solar energy to cook food was known for over a hundred years before solar cookers were first introduced. The technology used has changed very little. There are two main type of solar cooking devices – solar ovens and direct focusing solar concentrators.

Solar ovens are essentially boxes consisting of wooden bases and sides with glazed, open lids. A solar oven’s interior is well insulated to prevent heat loss, and often a second lid is used with a mirrored inner surface, which can be angled to reflect solar radiation through the glazed lid, and into the box.

Many different designs and models of concentrating cookers are available. But almost all designs are based on the use of a reflector which, when directed at the sun, reflector which, when directed at the sun, reflects and concentrates solar radiation on the central platform on which the cooking vessel is placed.

Solar cookers have not become popular because of one major drawback – they have to be directed towards the sun after every 10-15 minutes.

NOTE : Solar cooking can be done by using parabolic (dish-shaped) reflectors to focus sunlight on the food or on a pot that contains the food.