Thermal performance optimization and evaluation of a radial finned shell-and-tube latent heat thermal energy storage unit

Add of fin is a simple and effective way to enhance the thermal behavior of latent heat thermal energy storage (LHTES). The target of this research is finding the most appropriate radial fins arrangement to accelerate phase change material (PCM) melting process in vertical LHTES unit. The effect of adding aluminum fins which possess the much higher thermal conductivity compared to PCM on melting process was investigated by numerical simulation firstly. The full melting time of radial finned LHTES unit decreases 44.0% compared with LHTES unit without fin. Then, the effects of fin height and pitch on thermal performance are simultaneously considered. The dimensionless fin height of 0.642 is recommended in this study. The thermal performances of vertical finned LHTES with four different fin arrangements (lower fins, upper fins, middle fins and arithmetic fins) were explored. Numerical results show that the complete melting time could be reduced 49.9% by arithmetic fins. The root mean square (RMS) of liquid fraction is proposed to describe the uniformity of the melting process of PCM. In this study, the root mean square of the LHTES unit using arithmetic fins is the lowest in the four fins arrangements, following by lower fins, middle fins and upper fins. For maximizing thermal performance, adding arithmetic fins to LHTES is recommended.