Numerical investigation of solar energy storage by a salt gradient solar pond in several Moroccan cities

Abstract

Numerical investigation of solar energy storage by a Salt Gradient Solar Pond (SGSP) in several Moroccan cities (Marrakesh, Ouarzazate, Tangier and Ifrane) is presented in this paper. For this purpose, the SGSP considered is assimilated to an open parallelipedic cavity in which the vertical and bottom walls are thermally insulated. The one-dimensional numerical model developed in Python programming language is based on the energy balance of each SGSP zone in which the heat losses via the SGSP free surface are retained. The numerical results obtained from the model developed are satisfactorily compared and validated against those obtained experimentally and numerically from a literature study. According to the results of one year of the SGSP operation, the storage zone temperature and the energy stored in the SGSP located in Ouarzazate city are the highest and reach maximum values in July (about 128 °C and 146 MJ respectively). Moreover, comparisons between different mass flow rates (0.01 Kg/s, 0.05 Kg/s and 0.09 Kg/s) of heat exchanger placed in the storage zone show that the optimal one is 0.09 Kg/s as it ensures the maximum energy extraction.