Thermodynamic performance of cascaded latent heat storage systems for building heating

Decarbonization of building space heating is essential for China to meet its carbon neutrality goal by 2060. Cascaded latent heat storage (CLHS) coupled with electric heating is a promising technology to promote renewable energy consumption, reduce carbon emissions, and save on heating bills. However, few studies have focused on the thorough investigation of the superiority of the CLHS system over a non-cascaded system. This study investigated the effects of heat transfer fluid (HTF) flow rates, HTF inlet temperatures, and number of stages on the thermodynamic performance of non-cascaded and CLHS systems based on energy and entransy analysis. Results showed that, compared with the non-cascaded system, the charged thermal energy and discharged thermal energy of the two-stage CLHS system increased by 26.5%–44.6% and 19.8%–74.5%, respectively, and the entransy increase of cold HTF increased by 20.0%–75.7%; while, in heating systems, it is not guaranteed that thermodynamic performance improves by using more stages in the CLHS system.