A novel compensating fins configuration for improving the thermal performance of latent heat thermal energy storage unit

The low thermal conductivity of phase change materials (PCMs) severely limits the performance and operational capability of latent heat thermal energy storage (LHTES) systems. In this study, the authors not only first revealed the contradiction of the optimization strategy of the fins in the melting and solidification processes but also proposed a novel compensating fins configuration based on LHTES units with double sources (heat and cold sources) for promoting the performance and flexibility of the LHTES units. A transient two-dimensional numerical model using the enthalpy-porosity method is used to study the characteristics of energy transfer during heat storage, heat release, and heat storage-release process in the LHTES unit. The five developed types of compensating fins are well compared. The results illustrated that the unequal-length compensating fins reduced the melting and solidification time by 64.2% and 82.1%, respectively. Moreover, the unequal-length compensating fins increased the heat transfer rate by 155%, and the steady-state time was shortened by 73.3% in the heat storage-release process. Compensating fins configurations effectively improved the thermal performance and flexibility of the LHTES unit.