| 摘要 |
PROBLEM TO BE SOLVED: To allow the improvement in efficiency to be compatible with securing of reliability in a refrigerating system using CO2 refrigerant. SOLUTION: A refrigerant circuit comprises a compressor 1, a gas cooler A, a primary expansion mechanism C, a receiver for gas-liquid separation 7, a secondary expansion mechanism D, an evaporator B, a gas injection mechanism E and an inside heat exchanger 8. Thereby, the rise in the discharge temperature of the compressor on the basis of the inside beat exchange is suppressed by the injection of gas refrigerant by the gas injection mechanism E, while the improvement in the efficiency of the inside heat exchange by the inside heat exchanger 8 is contrived. Moreover, a refrigerating capacity is improved on the basis of the increase in evaporation enthalpy due to introduction of liquid refrigerant after gas-liquid separation into the evaporator B, and the improvement in the refrigerating efficiency is made compatible with securing of the reliabilty of the compressor 1 as these synergistic effects.
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