Exploring the properties of user defined phase change materials for thermal energy storage

In this paper, a 2D thermal energy storage (TES) is modelled and solved numerically in the software COMSOL Multiphysics. The aim of this study is to examine the suitability of relevant thermal properties for the selected system design for charging only. The system consists of a cylindrical tank with height 0.5m and diameter 0.5m, acting as a packed bed full of encapsulated phase changing materials (PCM). The heat transfer fluid is water, entering the system at 90°C at a velocity of 0.01m/s. The investigation of the relevant properties focuses on the effect of melting temperature, latent heat of fusion, density, thermal conductivity and specific heat capacity. The final temperatures at different for spheres at different positions across the tank length are recorded and the heat absorbed for said spheres is calculated. Results indicate that the liquid properties of the PCM are more dominant over the temperature reached by system than the solid ones. Furthermore, higher final temperatures have been noted for high thermal conductivity of the liquid. In contrast, high specific heat capacity of the liquid yields significantly lower final temperatures.