Modelling and Simulation of Helical Coil Embedded Heat Storage Unit Using Beeswax/Expanded Graphite Composite as Phase Change Material

Abstract

Latent heat storage systems are the sustainable methods to store energy both from conventional as well as renewable sources of energy. The geometry of thermal storage system as well as the phase change materials are important parameters to design an efficient thermal energy storage unit. In this paper modelling and Simulation of a shell and tube types thermal storage unit was performed using COMSOL Multiphysics using beeswax and its composite with expanded graphite as phase change materials. The beeswax was filled in the shell part of the thermal storage unit (TSU) while the heat transfer fluid is passing through the helical tube embedded in the phase change material. The model of the prepared experimental setup was simulated on the COMSOL Multiphysics and it was observed that the simulation data are in good agreement with the experimental data with only 6% and 7.5% difference for beeswax and composite material respectively. The enthalpy method was used to simulate the melting of beeswax in the thermal storage unit. It was also observed that the pattern of heat flow as well as solid-liquid interface moves in similar pattern in case of both experimental and modeled parts.