Thermal performance analysis and optimization of melting process in a buried tube latent heat storage system

This study aims to contribute toward enhancing the melting process of phase change material (PCM) inside a novel buried tube latent heat storage (BTLHS) system. The PCM is filled in the middle tube. The hot water flows down in the inner tube from the top of the system, then, changes the flow direction at the bottom of the system into the outer tube and flows out at the top of the system. The effects of different shell-to-tube diameter ratios, the fin number and the fin arrangement on the melting performance of the system are investigated and compared. The system performance is evaluated based on melting time, heat storage rate and contour plots of different temperatures and solid-liquid phase interface. The results show the obvious effect of the shell-to-tube diameter ratio on the melting performance. The value of the diameter ratio is considered 2.0 which has the best overall performance. For the best configuration (fin number of 20, fins arranged on the wall of the middle tube), the melting time is reduced by almost 42% and the heat storage rate is increased by almost 53% compared with the BTLHS system with no fins. This study contributes to the development of a novel heat storage system and efficient storage of heat energy.