Estimation of heat transfer performance of latent thermal energy storage devices with different heat transfer interface types: A review

Low and medium grade thermal energy is one of the most commonly used energies. Owing to environmental concerns, the centralized energy supply is assumed to become limited; therefore, the development of thermal energy storage has become a critical need for meeting thermal energy supply and demand. The latent thermal energy storage (LTES) technology has received widespread attention because it exhibits a high energy-storage density and is easy to manage. However, owing to the differences in device structures, phase change materials (PCMs), and working conditions, determining a systematic approach to comprehensively evaluate the heat transfer performance of LTES devices is difficult. In this study, the overall convective heat transfer coefficients from the PCM side are calculated and reviewed according to three types of heat transfer interfaces (HTIs) between the PCM and heat transfer fluid (HTF): flat surface, extended surface, and direct contact. The comparison results show that extensible and diversified HTIs are crucial for enhancing the heat transfer performance, indicating the importance of improving the accessibility between the PCM and HTF. Furthermore, the different heat transfer performances of devices and their improvement methods are clarified. In addition, the limitations associated with the innovative optimization of the HTI structures to be applied in devices are discussed.