Numerical study of solar latent heat storage unit using Paraffin Wax P116

The present work concerns the modeling and numerical simulation of the melting of a phase change material (PCM) in a storage unit of solar thermal energy. The studied storage unit consists of an enclosure filled with Paraffin wax which exchanges heat by forced convection with a heat transfer fluid (water) coming from a solar collector and circulating in a rectangular duct. All walls of the enclosure are assumed adiabatic except that in contact with the rectangular duct. A mathematical model based on the equations of conservation of mass, momentum and energy has been developed. These equations are discretized using the finite volume approach. The SIMPLE algorithm is adopted for the treatment of velocity pressure coupling. The equation of energy conservation of PCM was solved using the enthalpy method. A series of simulations was performed for meteorological data for the town of Marrakech: incident solar power, ambient temperature and wind speed to find the optimum configuration. The optimization aims to determine the mass of the PCM, the number of rectangular channels, the aspect ratio and the mass flow rate through the solar collector that maximize the efficiency of heat storage.