A heat pump is an energy-saving device that uses high-level energy to flow heat from a low-level heat source to a high-level heat source. As the low-level heat source of the heat pump, air is inexhaustible, available everywhere, and can be obtained free of charge. Moreover, the installation and use of air source heat pumps are relatively convenient. [1] The research, production, and application of air source heat pumps (also known as air-cooled heat pumps) in my country only developed rapidly in the late 1980s. The current products include household heat pump air conditioners, commercial unit heat pump air conditioning units and heat pump hot and cold water units.