Heat pump system and an air conditioning system

Compressor 1, condenser 2, expansion device 3 and evaporator 4 to be connected by piping to constitute a refrigerant circuit, the condensation temperature detection means 11 for detecting the saturation temperature of the condenser 2 as a condensing temperature, saturated evaporator 4 and evaporation temperature detection means 12 for detecting the temperature as the evaporation temperature, based on the condensing temperature and the evaporation temperature, at least calculates the average operating efficiency until defrosting completion from start of operation when the performed defrosting at present, operation in which a control device 50 for performing a process of determining the start of the defrosting of the evaporator based on the average operating efficiency was.