Manufacturing method of transition critical refrigerating cycle device

A manufacturing method of a transition critical refrigerating cycle device constituted by successively connecting a compressor, a gas cooler, a throttling device and an evaporator and having a supercritical pressure on a high-pressure side of the device, the method comprising:

• providing the gas cooler which cools a high-pressure refrigerant of the compressor by the flow of a refrigerant through refrigerant pipes of the gas cooler and the flow of air as the heat absorber over the refrigerant pipes of the gas cooler;
• providing a sub-cooler which cools an intermediate-pressure refrigerant of the compressor by the flow of the refrigerant through refrigerant pipes of the sub-cooler and the flow of air as the heat absorber over the refrigerant pipes of the sub-cooler, wherein the refrigerant pipes of the sub-cooler have a uniform heat transfer area per unit length of each refrigerant pipe;
• integrating the gas cooler and the sub-cooler to constitute a heat exchanger;
• setting a ratio of the number of refrigerant pipes of the sub-cooler to the number of refrigerant pipes of the whole heat exchanger to 20% or more and 30% or less;
• positioning the gas cooler on the air inflow side of the heat exchanger and positioning the sub-cooler on the air outflow side of the heat exchanger;
• arranging the refrigerant pipes of the sub-cooler in parallel with one another in a vertical direction on a refrigerant inlet side;
• and
• arranging the refrigerant pipes of the sub-cooler obliquely in relation to a vertical direction on a refrigerant downstream side, whereby
• the refrigerant pipes on the refrigerant inlet side of the sub-cooler are less densely arranged than the refrigerant pipes on the refrigerant downstream side of the sub-cooler.