Simultaneous charging and discharging processes in latent heat thermal energy storage: A review

This review presents a first state-of-the-art for latent heat thermal energy storage (LHTES) operating with a simultaneous charging-discharging process (SCD). These systems combine the thermal behaviour of a storage with a phase change material (PCM) and the behaviour of a heat exchanger with heat transfer between two heat thermal fluids (HTF). A bibliometric analysis is conducted to identify relevant documents and also to highlight the growing interest in scientific research for LHTES with a SCD. Existing studies are analysed according to the geometry of the storage, the heat transfer process to charge and discharge the PCM and the applications. In order to provide a complete review, studies are also categorized according to the method used to enhance heat transfer between the heat exchangers and the PCM. Based on the current state-of-the-art, the advantages of SCD compared to conventional LHTES with independent charging and discharging (ICD) are discussed in term of thermal performance and efficiency. To conclude, guidelines, recommendations and perspectives are suggested for future research to select the appropriate PCM, assess the thermal performance, design the storage and enhance heat transfer.