Capacity selection of air-source heat pump based on outdoor design temperature for heating

The calculation formulas of heat attenuation coefficient and frosting loss coefficient are given, and the model of air-source heat pump under heating condition is modified.Taking 11 typical cities in cold and severe cold zones as examples, this paper discusses the influences of outdoor ambient temperature and frosting on the balance relationship between heat supply and demand, the lowest temperature in the heating room and the unguaranteed days when the air-source heat pump is selected based on the outdoor design temperature for heating. The results show that both low outdoor ambient temperature and frosting will make the heating capacity of air-source heat pump lower than the building heating load, leading to lower indoor temperature and extension of unguaranteed days. Moreover, frosting has a more significant effect on the heating effect of air-source heat pumps selected based on outdoor design temperature for heating. It is recommended to multiply a correction coefficient on the basis of the original selection capacity based on the outdoor design temperature for heating, the correction coefficient can be 1.00 and 1.05 in the severe cold zone B and C, respectively, and between 1.15 and 1.30 in cold zones.