Numerical analysis of a solar thermal energy storage tank filled with phase change material under three fin arrangements

Phase change materials have been recently introduced as key thermal energy storage (TES) medium in several thermal applications, specifically in solar thermal energy systems. The thermal performance of three TES systems is investigated numerically. Stainless steel 304 was used to construct the storage units, and paraffin wax served as the latent TES material. Simulations were performed on TES systems with identical dimensions and different fin numbers (i.e. 10, 20 and 29). Under the weather conditions of Al Amarah, a city in Iraq, the simulations used heat transfer fluid at a constant flow rate of 1 L/h and a velocity of 0.001 m/s. Results showed that the tanks yielded volumetric heat capacities of 9702.89, 14727.97 and 21789.07 kJ/m³.K at 10, 20 and 29 fins, respectively. Moreover, the maximum latent heat distribution ranged from 10.39 to 23.01 J/kg.K, indicating remarkable energy contribution. The TES system with 29 fins showed the fastest charging and discharging times, attributed to the optimised heat transfer paths between fins, thus making it ideal for high-demand applications. © 2024