Numerical investigation on melting and thermal performances of a phase change material in partitioned cavities with fins for thermal energy storage

Abstract

The practical application of solid-liquid phase transition latent thermal energy storage devices is restricted by the low value of thermal conductivity in phase change materials (PCMs). To alleviate this problem, a proposal for a newly developed thermal energy storage unit with metal multiple partitions and flat fins coupled is presented in this paper. The design was constructed by dividing the typical vertical rectangular thermal energy storage unit into several partitions (1, 2, 4, and 8), including 4-fins and 8-fins in different partitions. A 2D transient solid-liquid phase change numerical model was firstly validated and then the effect of different configurations was numerically determined to obtain the thermal energy storage characteristics, velocity field, solid-liquid interface, temperature distributions, and thermal transfer performances. The results show that the optimized metal partitioned cavities lower the PCM's melting time with the maximum melting time reduction occurring at a value of 76.8 % compared to the common wooden partition. Because of increased thermal networks or enhanced local natural convection, increasing the cavity partitioning and fins shortens the melting time of the PCM. The 8-partitions cavity coupled with 8-fins generates the shortest melting time. Increasing the quantity of cavity partitioning and fins also leads to a reduction in the time needed to attain the largest amount of stored energy and an increase in the Nusselt number and power.