ABSTRACT
The solar pond is an artificial black-bottom pond or lake 1 to 2 metres deep in which convection is prevented by having a strong density gradient from the bottom to the top. In 1948 Dr Rudolph Bloch suggested that an effective solar collector could be created by avoiding convection in a stratified salt solution, i.e. by creating a density gradient in a pond. Claude and his French colleagues recognized the ocean as the cheapest form of solar collector. The possibility of building large central power stations – in the megawatt class – using solar collectors of conventional type, seems remote. Three major problems require to be solved in a reasonable manner to make the solar pond practical and economic. These are: the extraction of heat from the bottom without disturbing the density gradient; the suppression of upper zone mixing due to the wind; and methods for keeping the pond clean.
