Study of solar thermal energy storage using different materials in uniform tanks

Recent studies have focused on developing large-scale thermal energy storage systems for numerous thermal applications. To preserve the thermal energy harvested from solar energy, three new thermal tanks; uniform in shape, dimensions, and metal type, were used. Different thermal storage materials, such as phase change material (PCM), gravel, and water were employed, and the latter was assigned as a reference for comparison. These three materials were placed at similar locations in the thermal tank. Simulations were performed using COMSOL® Multiphysics 6.1 under similar operating conditions, constant flow rate and speed to compare the three cases. The study confirmed the amount of heat stored and the time required during the thermal battery charging process. The results exhibited that the tank containing PCM (RT-50) had a thermal capacity of 14455.47, while that contained gravel and water showed 1239.277 and 4195.21J/(kg.K), respectively. Moreover, the internal energy of the PCM was 83667.51 kJ/kg, and the energy of the gravel was 52012.30 J/kg, indicating the importance of the number of fins and their contribution to enhancing thermal conductivity, energy harvesting, and accelerating charging and discharging processes. The results collected during the experiment confirmed that the modification in the design and improvement of thermal conductivity provided by the PCM are the best in energy storage.