Tag: renewable and non-renewable resources

A solar cooker is a device which uses the energy of direct sunlight to heat or cook. 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. 

There are two primary means of achieving desalination using solar energy, through a phase change by thermal input, or in a single phase through mechanical separation. Phase change (or multi-phase) can be accomplished by either direct or indirect solar distillation. Single phase is done by the use of photovoltaic cells to produce electricity to drive pumps.

The value of solar constant is fixed and it is equal to $1.951Kcal\quad m^{-2}minute^{-1}$  which can be rounded off.