A numerical study on effects of heat transfer fluids, copper mesh in packed bed and porosity, on charging time of paraffin based packed bed thermal energy storage

Abstract

AbstractIn this study, a novel configuration of the latent heat thermal energy storage module based on the packed bed of encapsulated phase change material is investigated. The module is modeled and simulated using a Multiphysics tool COMSOL. The simulation results are validated with the experimental data. Using the validated model, initially, water was used as heat transfer fluid, and then refrigerant R‐134 and R‐22 were also used as heat transfer fluid (HTF) to predict the impact on the charging time. The comparison in terms of their thermo‐physical properties is also carried out. The results indicated that by using refrigerants (R‐134 and R‐22) as HTF, decreased the charging time. When the water was used as HTF, it took 11 hours to completely charge the system. Whereas, the charging time for R‐134 and R‐22 was 8.75 and 8.4 hours, respectively. It was also observed that edges of packed bed were melting much slower than the remaining bed. Therefore, to increase the transfer of heat near the edges, geometry of the module is modified and their impact is investigated.