Combination Effects of HTFs and Moroccan Rocks on the Thermal Performances of a Packed bed Thermal Energy Storage System

High Temperature Thermal Storage (TES) is a compelling technology ensuring the continuous generation of solar power and plays a major role in the industrial field. Indeed, the choice of the optimal storage material and the suitable heat transfer fluid (HTF) remains a great challenge. The main objective of this work is to make a numerical study of the thermal behavior of a thermocline storage system. The energy conservation equations associated with their boundary conditions have been solved numerically in the two field media (solid and fluid) constituting the packed bed thermal energy storage (TES) system. Three types of local rocks were used as storage materials and also three different types of heat transfer fluid (HTF) were considered too. The obtained simulation results show that the fluid/rock combination has an optimum thermal storage quantity and a good efficiency. These results have been validated and they are in good agreement with the literature.