Performance Estimation of a Latent Heat Thermal Energy Storage System with Different Packing Module Arrangements, Boundary Conditions and Melting Models

Abstract

ABSTRACTIn a latent heat thermal energy storage system, the shape of the container for encapsulating the phase change material (PCM) and the arrangement of the PCM vessels within the thermal storage tank have a high influence on the performance of the thermal storage tank. In the present study, a newly designed PCM container was used to investigate the effect of the arrangement of the packing module on the performance of the thermal storage tank. To reflect an actual situation, the system should be modeled using the unconstrained melting model, which includes a density difference between the solid and liquid PCM, and also the convective boundary condition with heat transfer fluid should be applied. The amount of deviation from a real situation was analyzed for simplified models of a constrained melting model and an isothermal boundary condition, which have been commonly used in most previous works. The horizontal arrangement of the packing module showed higher performance than the vertical arrangement. Compared to the unconstrained melting model, the constrained melting model underestimated melting by 50 min and 70 min for the horizontal and vertical arrangements, respectively. Compared to the convective boundary condition, the isothermal boundary condition overestimated melting by 115 min and 100 min for the horizontal and vertical arrangements, respectively.