Patent ID: 7788945

Claim:
An air conditioner configured by appropriating existing refrigerant pipes of an existing air conditioner to update a refrigerant circuit of the existing air conditioner, the existing air conditioner utilizing an existing refrigerant and an existing refrigerating machine oil, the existing refrigerant being a chlorofluorocarbon (CFC) or a hydrochlorofluorocarbon (HCFC) refrigerant, and the existing refrigerating machine oil being a mineral oil or an alkyl benzene, the air conditioner comprising: an updated refrigerant circuit including a compressor, a heat source heat exchanger, an expansion mechanism, a utilization heat exchanger, and the existing refrigerant pipes, the updated refrigerant circuit being filled with a working refrigerant and a working refrigerating machine oil that includes an acid trapping agent that detoxifies acid components remaining in the existing refrigerant pipes, the working refrigerant being a hydrofluorocarbon (HFC) refrigerant, and the working refrigerating machine oil being an ethereal or ester oil; a mixer disposed in the updated refrigerant circuit to mix the acid components with the acid trapping agent during a refrigeration cycle operation of the updated refrigerant circuit, the mixer being disposed such that the working refrigerant flowing through an intake pipe of the compressor passes through an inside of the mixer, and the mixer being configured to collect the working refrigerating machine oil; and an oil lead-out pipe connected to the mixer that is configured to return the working refrigerating machine oil collected inside the mixer to the intake pipe of the compressor.