Solar Pond - An OverView

A solar pond is a device which traps the heat in sunlight and makes it available for power generation.  A solar pond consists of a reservoir of salt water. The salt water in any reservoir has an inherent salinity gradient.  That is, the water at the lower layers will have a higher concentration of salt (around 90%) as compared to water at the top layer (30% salinity).

The water in the reservoir is transparent as to allow sunlight to penetrate to the deeper layers.  When sunlight falls on the bottom of the reservoir.  It heats the bottom layers of the salt water.  When normal water is heated, it tends to rise up due to convection and the water circulates. 

However, since the pond is filled with salt water, the hot water is trapped in the lower layer of the pond as it cannot rise up due to the high density.  This heat is removed by means of a liquid which passes through a pipe which runs through the lower layers of the pond.  The fluid in this pipe is kept in circulation by means of a pump.  this heat is used to heat water in a boiler which can be used to power a turbine and a generator.