On increasing the thermal mass of a salinity gradient solar pond with external heat addition: A transient study

In salinity gradient solar ponds (SGSPs) solar thermal energy is mainly stored in the lower-convective zone (LCZ) the volume of which defines the thermal mass of storage. The present study explores the provision of increasing the heat storage in a SGSP by increasing the thermal mass of it. It also addresses the method of enhancing the thermal performance of a SGSP by increasing the thermal mass, while adding heat from external sources. Earlier studies have proved that adding external heat to the SGSP for storage enhances the thermal performance of it significantly. This study aims to prove that increasing the thermal mass of storage further increases the energy efficiency of a SGSP when external heat is added to it. A hybrid system of a SGSP coupled with evacuated tube solar collectors (ETSCs) is used in this study. Several parameters like storage temperature in LCZ, heat addition flux and heat addition efficiency of ETSC, instantaneous efficiency of SGSP, heat extraction from SGSP are studied in this paper for different cases of with and without heat addition and with normal and enhanced thermal mass. It is found that increasing thermal mass can significantly enhance the thermal performance and efficiency of a SGSP