Effects of fins arrangement and parameters on the consecutive melting and solidification of PCM in a latent heat storage unit

This study is to investigate the characteristics of consecutive melting and solidification of a phase change material (PCM) in a horizontal double tube LHS unit. Fins is used to improve the heat transfer rate on the PCM due to its low thermal conductivity. A two-dimensional symmetric simulation model with considering natural convection is established. Enthalpy-porosity technique is used for modeling the phase change process. The effects of fins arrangements, number (N) and length (L) on the heat storage performance were studied. In addition, the effect of outer shell material of the finned LHS unit was studied. Moreover, the interactions among N, L, outer shell material and fins arrangement are considered. Results show that the fins of straight design shows a higher heat transfer enhancement than other arrangements, especially for the cases with small fins number (N < 6) and low thermal conductivity of outer tube material. It was also found that less long fins are more efficient in increasing the phase change rate than more short fins with the same total fins length.