09. Heat and Mass Transfer

Latent heat storage has a much higher heat storage density than sensible heat storage because it can store the phase change heat of a substance. Due to its advantage, Latent heat storage system is a promising system that can store large amounts of heat in a limited space or minimize the space required for heat storage. An important problem to be solved in latent heat storage systems is the long time required for heat storage. To solve this problem, it is necessary to increase the thermal conductivity of the latent heat storage material (LHSM) and to promote the melt convection during the melting process. This study shows experimental results of the melting process of LHSM made of dispersed fine multi-walled carbon nanotube (MWCNT) with very high thermal conductivity in a rectangular tank with a vertical flat heat transfer surface. The measurement sample is a mixture of 0.02 mass% MWCNT dispersed in paraffin-based LHSM with a melting point of 50.6℃. Heat storage experiments are conducted by observing heat storage behavior using a heat storage tank with vertical left and right flat heat transfer surfaces. The effect of MWCNT dispersion was observed in the range from 50 to 90% melting rate, and it was confirmed that this was caused by accelerated melting in the upper part of the storage tank. However, the mechanism of accelerated melting at the top of the tank has not yet been clarified. This paper describes the results of investigating the effect on the melting process by observing changes in MWCNT distribution during melting process.

Prof.

Yasutaka HAYAMIZU