Air conditioner

An air conditioner comprising:

• a refrigerant cycle having:
• an evaporator which is disposed in a blowing duct and cools by refrigerant evaporation;
• a compressor setting the evaporated refrigerant at high temperature and high pressure;
• a first refrigerant-to-water heat exchanger heating cooling water by heat transfer from the refrigerant discharged from said compressor;
• a first expansion device controlling the decompression of the refrigerant discharged from said first heat exchanger;
• a second refrigerant-to-water heat exchanger transferring heat between the refrigerant discharged from said first expansion device and the cooling water;
• a second expansion device controlling decompression of the refrigerant discharged from said second heat exchanger;
• an evaporator inlet refrigerant temperature detection means of measuring a temperature of the refrigerant of which decompression is controlled by said second expansion device;
• a control means of controlling said first expansion device and said second expansion device using a value detected by said evaporator inlet refrigerant temperature detection means, and
• a cooling water cycle having:
• a heater core which is disposed on the downstream side of said evaporator on the basis of a blowing direction in said blowing duct and which heats blowing air by the heated cooling water;
• a radiator cooling the cooling water;
• a pump circulating the cooling water cooled by said radiator;
• a power engine cooled by the cooling water fed by said pump;
• and said first heat exchanger and said second heat exchanger.