Numerical study on performance enhancement of latent heat storage unit

A three dimensional model for a shell-and-tube latent heat storage (LHS) unit was established to investigate the effect of liquid PCM natural convection on the performance. The enhancement effects of the outside enhanced tube and the bilateral enhanced tube were comparatively studied with the smooth tube. The results show that the natural convection can cause nonuniform distribution of solid-liquid interface and the nonuniformity can be weakened by using the designed enhanced tubes. At the same time, the presented enhanced tube can reduce the PCM melting time and total charging time. Compared with the PCM melting time of the smooth tube, the PCM melting time of the outside enhanced tube is reduced by 18.0% and the PCM melting time of the bilateral enhanced tube is reduced by 52.5%. In a conclusion, the presented finned enhanced tube can not only weaken the nonuniform distribution of solid-liquid interface caused by liquid PCM natural convection, but also enhance the LHS performance.