Box-type solar cooker consists of an insulated box, metallic cooking tray sat inside the box, double glass lid on the cooking tray, and a reflecting mirror fitted on the underside of the lid of the box. The cooking tray is insulated on the sides and bottom. The incoming solar radiation falls onto the double glass lid and passes through it to strike the blackened cooking pots and the cooking tray. The heat is absorbed by the blackened surface and gets transferred to the food inside the pots to facilitate cooking. The mirror reflector is set in such a way to reflect the solar radiation falling on it to the cooker box. Up to four black painted vessels are placed inside the box. The cooker takes 1? to 2 hours to cook items such as rice, lentils and vegetables. The cooker may also be used to prepare simple cakes, roast cashew nuts, dry grapes, etc. It is an ideal device for domestic cooking during most of the year, except for the monsoon season and cloudy days. It however cannot be used for frying or chapatti making.
The Indian Standard (IS 13420: 2000) defines the specifications and the performance parameters of box-type solar cookers.