Abstract: In order to solve the frosting problem of household air source heat pump (ASHP) operating under the condition of the low temperature environment, the most widely used defrosting method is reverse cycle defrost. However, the fundamental problem for such a method is that there is insufficient heat available for ASHP during defrosting, the heat storage defrosting mode is an ideal method. By reporting on an experimental study of the effectiveness of the heat storage defrosting mode, disodium hydrogen phosphate dodecahydrate is used as heat storage phase change material. Three factors, heating capacity, defrosting time and temperature fluctuation, to compare the difference between the heat storage defrosting system and the conventional reverse cycle defrosting system. Results indicated that the use of this PCM-based defrosting method could help increase the cycle heat, shorten defrosting time. The indoor temperature fluctuation of is reduced from the normal 7℃ to 2℃ during defrosting. The heat storage defrosting mode can greatly improve the thermal comfort of the room.

Key words: Disodium hydrogen phosphate dodecahydrate, Heat storge, Defrosting, Phase change material, Thermal comfort