Transient thermal performances of a salt gradient solar pond under semi-arid Moroccan climate using a 2D double-diffusive convection model

A two-dimensional numerical study is conducted to investigate quantitatively and qualitatively the thermal characteristics of a small-scale salt gradient solar pond (SGSP) operating under semi-arid climate (Marrakesh-Morocco). A realistic model was formulated based on the Navier-Stokes equations and the energy and salt transport equations. This developed model ensures an appropriate treatment of the boundary conditions, especially at the free surface of the pond in contact with the ambiance. The internal heating engendered by the absorption of solar radiation is considered in this study. The hybrid Finite-Volume Lattice-Boltzmann method is used; its performances make possible the approach of such a complex problem. After five days from the start of the heating process of the pond, the operating temperature in the heat storage zone has increased from 25 °C to reach 49.4 °C and the energy stored in this zone has slightly exceeded 40 MJ. The storage daily efficiency of the SGSP is seen to vary in the range from 25.6% to 36.5%. The preliminary results obtained highlight the important storage potential of the experimented SGSP.