A TREE-SHAPED LAYOUT HEAT PIPE TO ENHANCE HEAT TRANSFER IN A PHASE-CHANGE MATERIAL STORAGE PROCESS

Phase-change materials (PCM) are promising in energy storage. However, the low thermal conductivity of a PCM limits its practical application. A tree-shaped layout heat pipe was studied to improve the heat transfer performance in PCM energy storage. Based on the thermal imaging picture distribution of conventional heat pipes within the PCM during the heat storage process, tree-shaped layout heat pipes have been designed. Also, their thermal performance was experimentally compared with that of conventional heat pipes. Experimental results proved that the bending of heat pipes had minimal effect on its own thermal performance, and the difference in average temperature between tree-shaped layout and conventional heat pipes is 0.9%. A PCM containing such tree-shaped layout heat pipes melted 15.2% faster than a PCM with conventional heat pipes. The thermal resistance of a PCM with these tree-shaped layout heat pipes decreased by 41.7% compared with that of a PCM with conventional heat pipes. Also, tree-shaped layout heat pipes reduced the thermal resistance of the PCM mainly before phase change in the melting process, while this layout had less impact after the completion of melting.