Thermal behaviour of salt gradient solar ponds

Abstract

A numerical model has been developed to study the thermal behaviour of salt gradient solar ponds under different operating conditions. A cylindrical solar pond system with a thermal sink below and around the pond is also modelled to determine the heat losses to the earth. In these calculations, the solar pond is considered as a steady-state flat-plate collector. The effects of the thickness of three different zones and insulating materials below and around the pond on the overall thermal performance of the pond are studied. There is an optimum thickness of the non-convective zone for which the heat storage is maximum. The pond bottom and side heat losses are reduced using some low-cost insulating building materials such as dry dune sand, dry mica powder and dry marble dust below and around the pond. The results of a comparative study indicate that heat losses are considerably reduced with marble dust insulation and the solar thermal energy retaining capability of the pond is improved.