BEHAVIOR OF PHASE TRANSITION AND HEAT TRANSFER CHARACTERISTICS IN A LATENT HEAT STORAGE UNIT WITH COMPOSITE MATERIAL

A composite heat-storage material composed of organics and metal fiber was proposed and examined experimentally. By the addition of copper fiber up to 1 volume percent in naphthalene, supercooling on solidification was greatly reduced and apparent thermal diffusivities were found to increase threefold. The rate of heat release from the composite material was analyzed by a model based on the experiments, in which the heat transfer in the solid phase is governed by conduction and the liquid-phase transfer is expressed in terms of the heat transfer coefficient. Also, the presence of a mushy zone at the phase boundary is assumed where the temperature is uniform. The thickness of the mushy zone was determined and the temperature change during the heat discharge was well analyzed. Consequently, the composite heat-storage material was found to be promising.