Performance enhancement of latent heat thermal energy storage system by using spiral fins in phase change material solidification process

Latent heat thermal energy storage systems (LHTESS) have recently gained attention due to the critical demand for clean energy production and storage. The influence of spiral fins on the performance augmentation of a vertical tube-shell LHTESS in the solidification process was studied numerically. Different formation of fins which includes the quadruple, triple, double and single fins were studied. Amount of phase change material (PCM) mass inside the PCM enclosure was preserved equal in all cases and the length of the fins were adjusted for different fin numbers to keep the surface of heat transfer constant to find the optimized fin number. The phase change process was simulated by adopting the enthalpy-porosity technique. It was observed that the triple fin case outperformed other cases and the single fin case showed the least enhancement. When comparing the different cases while the heat transfer surface was kept constant, the triple fin case shows better performance in terms of time averaged Nusselt number and total solidification time respectively. It was revealed that the performance enhancement was not directly proportional with the number of fins and there was a trade-off between fin number and length of each fin.