Abstract
Latent heat storage technology is an efficient way of heat storage due to its high energy storage density and stable energy storage temperature. Cascaded latent heat storage (CLHS) is a promising technology to improve the heat transfer rate and energy efficiency in the packed-bed thermal energy system (PBTES). In this paper, a 1-D two-phase model is established to study the thermal performance of cascaded latent heat storage (CLHS) system. The study used energy and exergy analysis theories to investigate the effects of heat transfer fluid (HTF) flow rates, HTF inlet temperatures, and layout of PCMs on thermal performance of PBTES. The indexes of heat storage density, average heat storage rate, effective heat storage time and exergy efficiency are used to compare the performance of single-PCM and CLHS systems. The results show that the CLHS system has a higher heat storage and thermal density compared with single-PCM heat storage systems. The exergic efficiency of CLHS is 0.93, which is much higher than PBTES. And increasing the inlet temperature or fluid flow rate can be the effective way to improve the thermal performance of packed bed thermal energy system.
