Phase Change Heat Transfer During Melting and Resolidification of Melt Around Cylindrical Heat Source(s)/Sink(s)

Abstract

Melting and resolidification of a phase change material around two cylindrical heat exchangers spaced vertically have been investigated experimentally. Experiments have been performed to examine the effects of the cylinder surface temperatures on heat transfer during the melting and freezing cycle. The processes have been clarified on the basis of observations of timewise variations in the solid/liquid interface and of temperature distribution measurements in the phase change material. The results show that the solid/liquid interface contour during the melting and resolidification of the liquid from the upper cylinder is greatly affected by the surface temperature of the lower cylinder. The results show that multiple liquid regions may develop in the phase change material around the embedded heat sources/sinks, and the temperature swings and melting and freezing periods need to be selected properly in order to effectively utilize the phase change material in a latent heat energy storage unit.