Investigation of the thermal performance of cascaded latent heat thermal energy storage system based on composite phase change materials

This paper conducts thermodynamic analysis of the cascaded latent heat thermal energy storage system that is applicable to building heat storage, with focus on using the high performance composite phase change materials (CPCM). The 7.5wt. %EG/MgSO47H2O-KAl(SO4)212H2O were used as PCM, the performance of cascaded system and single-stage system were compared. The results show that exergy efficiency, heat charging rate and discharging rate of the cascaded system compared with the single-stage system can be increased at most by 11.6%, 49.7%, and 9.7%, respectively. This work has important guiding significance for the applied research of the heat storage system with the CPCM.