<P> A solar cooker is a device which uses the energy of direct sunlight to heat, cook or pasteurise drink and other food materials . Many solar cookers currently in use are relatively inexpensive, low - tech devices, although some are as powerful or as expensive as traditional stoves, and advanced, large - scale solar cookers can cook for hundreds of people . Because they use no fuel and cost nothing to operate, many nonprofit organizations are promoting their use worldwide in order to help reduce fuel costs (especially where monetary reciprocity is low) and air pollution, and to slow down the deforestation and desertification caused by gathering firewood for cooking . </P> <P> 1) Concentrating sunlight: A mirrored surface with high specular reflectivity is used to concentrate light from the sun on to a small cooking area . Depending on the geometry of the surface, sunlight can be concentrated by several orders of magnitude producing temperatures high enough to melt salt and smelt metal . For most household solar cooking applications, such high temperatures are not really required . Solar cooking products, thus, are typically designed to achieve temperatures of 65 ° C (150 ° F) (baking temperatures) to 400 ° C (750 ° F) (grilling / searing temperatures) on a sunny day . </P>

What are the advantages and disadvantages of a solar cooker