Development in multiple-phase change materials cascaded low-grade thermal energy storage applications: A review

The efficient use of thermal energy is one of the most important aspects that govern the development of any nation. But the disparity between demand and supply of thermal energy has stimulated researchers to design efficient thermal energy storage (TES) systems. The latent heat TES (LHTES) utilizing phase change material (PCM) is one of the most effective methods for the storage of energy in confined space. The LHTES encounters the issue of the non-uniform driving temperature difference between PCM and heat transfer fluid that causes a slow rate of heat transfer, and asynchronous phase transition. To achieve uniformity in temperature distribution and for instant storage and release of thermal energy, the concept of cascading of multiple-phase change materials (M-PCMs) in the LHTES system has been established. The review paper summarizes the development in M-PCMs cascaded LHTES (C-LHTES) utilized for low-grade thermal energy storage applications (cold: below 20 degrees C and low-temperature heat: between 20 degrees C and 100 degrees C). The effect of thermodynamic properties of PCMs, selection, and stacking of PCM, operating and geometric parameters have been reviewed on the performance parameter of M-PCMs C-LHTES. To improve the heat transfer rate, energy, and exergy efficiency of LHTES, the innovative designs, and arrangements, and the use of M-PCMs in conjunction with thermal conductivity enhancers and surface enhancers have also been discussed. The results of research work in the field of M-PCMs C-LHTES are summarized in tabular form according to the applications. The key findings of the review for each application and guidelines for selecting phase change temperature of M-PCMs, preferred number of stages, order of M-PCMs for cascading, etc. are presented in conclusion. The scope of future work in the field of M-PCMs C-LHTES systems has also been presented.