solar oven

solar oven, a device that harnesses sunlight as a source of heat for cooking foodstuffs. The solar oven is a simple, portable, economical, and efficient tool.

Especially in the developing world, solar ovens are much to be preferred over other methods of cooking. Of the many advantages of solar ovens, the greatest is its freedom from the necessity for fuel. Solar ovens thus not only remove any persistent labour or monetary costs associated with cooking, but by conserving often scant resources in the long run they prevent deforestation and desertification. Solar ovens are also useful in the developed world whenever electricity is unavailable and traditional open fires are undesirable, such as while camping.

Types of solar ovens

Solar ovens are available in many designs that employ an array of different materials and approaches. Each design must be capable of concentrating sunlight from over a wide area to a central point. At that central point, a black-surfaced vessel helps convert the sunlight into heat, which is used to cook the food. Further, once the heat is generated, it must be trapped and insulated from the cooler air outside the cooker. The basic designs are as follows:

• A box cooker consists of a number of mirrored panels that focus their beams toward an insulated box structure, which has a transparent top used to admit the solar radiation. Black-painted cooking pots and pans are placed inside the box.
• A hybrid cooker is a box cooker equipped with a supplementary electrical heating system, which can be used at night and when it is overcast or cloudy. Those tend to be larger, fixed installations for use by a community or group.
• Parabolic cookers—which use a parabolic mirror to focus the sunlight to a central point at which the cooking container is placed—are capable of generating high temperatures, but they are more difficult than the box cooker to construct.
• Panel cookers are the least-expensive type of solar cooker. The panels, often made of corrugated cardboard and covered with an inexpensive reflector such as aluminum foil or Mylar, focus the Sun’s rays onto a black cooking pot, which is kept inside an insulating plastic bag.

Cooking with a solar cooker

Solar cooking requires a slightly different approach to food preparation. Because food cooks faster in smaller pieces, those who use solar cookers often chop food into small pieces to decrease the amount of time required to complete the cooking. Further, the device is turned to face the Sun and may require regular realignment to ensure that it receives the optimum solar gain. Finally, food prepared in a solar cooker generally is not stirred or agitated, in part because that activity slows the cooking process and in part because a lifted lid allows heat to escape.