Recent progress in phase change materials storage containers: Geometries, design considerations and heat transfer improvement methods

The potential for phase change materials (PCMs) has a vital role in thermal energy storage (TES) applications and energy management strategies. Nevertheless, these materials suffer from their low thermal conductivity and hence heat transfer enhancement techniques should be applied to enhance their thermophysical properties. This review focuses on the geometrical configurations of PCM containers and their design considerations, aims to improve the performance of TES systems. Various methods for enhancing heat transfer of PCMs (the main challenge in container design) include microencapsulated PCMs, insertion of fins, the combination of fins and nanoparticles, the use of metal foams and graphite, and the doping of high photothermal materials are also extensively discussed as well. Moreover, this paper highlights various designs of PCM-finned storage systems and discusses deeply their key parameters to find out the suitable design for optimum melting and solidification rate of PCM. The reviewed results showed that the rectangular PCM container is the effective container for the bulk storage due to its high melting rate and storage efficiency. Moreover, the use of longitudinal finned geometry within PCM integrated triplex tube heat storage units significantly achieved better heat transfer performance compared to the other finned geometries. Additionally, the improvement of the heat transfer of PCM by the deployment of fins is more effective than the hybrid combination of fins and nanoparticles. Further optimization and experimental studies are recommended to explore new hybrid compound intensification techniques such as the triple combination of fins, expanded graphite, and heat pipes with multiple PCMs that augment the thermal performance of TES systems.