Thermal and Fluid Characteristics of a Latent Heat Thermal Energy Storage Unit

Latent heat thermal energy storage (LHTES) is a promising way to smooth the discrepancy between energy supply and demand, and it is now becoming increasingly significant in the heating and cooling of buildings. However, the low thermal conductivity of the available PCMs require more efficient configuration of LHTES system in reducing the melting time. In order to evaluate the dynamic thermal performances of LHTES unit in shell and tube heat exchanger, the two-HTF-passage configuration and single-pass configuration are numerically investigated. The results show that the central and annular injection in two-HTF-passage configuration has little influence on the transient melting interface location and temperature in the PCM domain and both can effectively enhance the phase change heat transfer, but the HTF tube injection in single-pass configuration shows a significantly poor performance.