Investigation of thermal and electrical performance in a salt gradient solar pond

Abstract

The performance of a salt gradient solar pond (SGSP) invariably depends on the properties across its various zones. This paper presents an experimental study of salt diffusion, electrical and thermal performance of a trapezoidal-shaped SGSP. The variations of various parameters such as salt concentration, temperature gain, electrical conductivity (EC), thermal conductivity, density, specific heat and total dissolved solids (TDS) are studied across different zones of SGSP. This study reveals that for a given level of solar insolation, the rate of temperature gain within the lower convective heat zone (LCHZ) is high during the initial stages of operation where the salt diffusion rate is slow. Temperature gain of 16.06° is observed during a month comprising both rainy and sunny days. Within LCHZ, it is found that thermal conductivity, density and specific heat depend strongly on the salinity and their dependence on the temperature is relatively weaker. However, the effect of temperature on these three parameters is observed in the upper convective cold zone (UCCZ). Additionally, in UCCZ and LCHZ, TDS and EC depend on both salinity and temperature. The present observations are proposed to be useful in applications related to solar pond based desalination and energy generation.