Thermal performance assessment of a trapezoidal salinity gradient solar pond with different sidewall inclination angles: a numerical investigation

Trapezoidal salinity gradient solar pond (TSGSP) represents a successful device to gather solar energy and stock it in the form of heat for a long time. The TSGSP is an important device to store thermal energy for exploiting it in several thermal engineering applications that require a great amount of hot water. The angle of the sloped sidewall of the TSGSP greatly influences its thermal performance, affecting fluid flow, heat and mass transfer. Hence, the principal aim of the present investigation is to assess how the sidewall inclination angle affects the thermal performance of a trapezoidal salinity gradient solar pond. The assessment is done to understand the impact of various sidewall inclination angles on hydrodynamic, heat and mass transfer behaviours of the TSGSP. The idea of the sloping sidewall of the TSGSP is to reduce the volume of salt water in order to enhance its temperature in the lower convective zone (LCZ). The dimensionless equations of continuity, momentum, temperature and salt concentration inside the TSGSP with different sidewall inclination angles and having the same area of top water surface and height are resolved by means of the finite-volume method to show how the sidewall inclination angle impacts the temporal evolution of temperature, salt concentration and velocity fields inside the TSGSP. The numerical results described the effect of different values of sidewall inclination angle on the thermosolutal natural convection in a TSGSP. These numerical results show that the sidewall inclination angle has an important effect on improving the temperature of salty water in the LCZ. Thus, it is suggested to employ a TSGSP with a low sidewall inclination angle to augment the temperature and concentration of salt water in the LCZ.