Vehicle air-conditioning apparatus updating method and vehicle air-conditioning apparatus

A method of updating a vehicle air-conditioning apparatus such that a first air-conditioning apparatus which is disposed in a frame mounted on a vehicle and in which a first refrigerant is used is updated to a second air-conditioning apparatus using a second refrigerant and the second air-conditioning apparatus is disposed in the frame, the method comprising the steps of:

• removing at least a first compressor, a first heat source side heat exchanger, a first pressure reducing device, and a first use side heat exchanger constituting a refrigerant circuit of the first air-conditioning apparatus from the frame;
• assembling the second air-conditioning apparatus such that a second compressor, a second heat source side heat exchanger, a second pressure reducing device, and a second use side heat exchanger are arranged at predetermined positions in the frame;
• and
• charging the second air-conditioning apparatus disposed in the frame with the second refrigerant,
• wherein an inverter driving the first compressor included in the first air-conditioning apparatus controls the second compressor depending on a measured value of at least one of a pressure sensor and an outside air temperature sensor arranged on a discharge side of the second compressor such that an amount of the refrigerant circulating in the second air-conditioning apparatus is larger than that in the first air-conditioning apparatus.