115 The Experimental Study of Composite Phase-Change Thermal Storage Method

Thermal storage technologies are widely used in energy conservation, such as solar energy utilization, balancing electrical power load, recovery of industry waste heat. Most of the PCMs are poor heat conduction media, the main thermal resistances in the heat transfer process between the PCM and the heat transfer medium is on the PCM side. In this paper, an electric heating unit with composite phase-change thermal storage technology is designed and manufactured. The practical application of this electric heating unit is space heating, so docosane is chosen as the PCM in our experiment. Considering the heat transfer process, docosane has the proper temperature of melting point and a quite high latent heat. The performance of the unit under various operation modes is investigated experimentally. The temperatures of latent and sensible thermal energy storage material in thermal storage process are measured and the thermal storage capacity is calculated. The comparison between composite phase-change thermal storage method and sensible thermal storage method is carried out.