Daikin Industries, Ltd.

Koji Shibaike

Shigeharu Taira

Junichirou Tanaka

A refrigerating device has a refrigerant circuit having a compressor ( ), an indoor heat exchanger ( ), a main motor operated valve (EV ), and an indoor heat exchanger ( ) connected in a loop, and uses, as a working medium, an R32 refrigerant or a mixed refrigerant containing R32 at at least 70 wt %. A supercooling heat exchanger ( ) is disposed between the indoor heat exchanger ( ) and the main motor operated valve (EV ), and the liquid side of the refrigerant circuit are connected to the gas side by by-pass pipes ( ) through the supercooling heat exchanger ( ). A supercooling motor operated valve (EV ) is disposed at the by-pass pipe ( ) upstream of the supercooling heat exchanger ( ). A discharge temperature detected by a discharge temperature sensor ( ) is determined by a discharge temperature determination part ( ), and based on the determination result, the opening of the supercooling motor operated valve (EV ) is controlled so as to control an amount of the refrigerant flowing through the by-pass pipes ( ), whereby, using the working medium containing R32, the discharge temperature of the compressor is optimized without reducing the efficiency, and the COP and reliability are improved.

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Kusatsu, Japan

Koji Shibaike