| 摘要 |
This multi-stage compression refrigeration cycle device is equipped with: a low-stage compression mechanism (12a); a high-stage compression mechanism (11a); a radiator (13) which dissipates the heat of the high-pressure refrigerant discharged from the high-stage compression mechanism; an intermediate-pressure expansion valve (15) which decompresses/expands the high-pressure refrigerant flowing out from the radiator into an intermediate-pressure refrigerant and causes the intermediate-pressure refrigerant to flow out to the suction side of the high-stage compression mechanism; a low-pressure expansion valve (17) which decompresses/expands the high-pressure refrigerant flowing out from the radiator into a low-pressure refrigerant; an evaporator (18) which causes the low-pressure refrigerant decompressed/expanded by the low-pressure expansion valve to evaporate through heat exchange with blowing air and flow out to the suction side of the low-stage compression mechanism; a control device (20) which controls the rotational speed of the low-stage compression mechanism and the high-stage compression mechanism; and a physical quantity sensor (24, 25) which detects a physical quantity correlated with the pressure of the low-pressure refrigerant. On the basis of the physical quantity detected by the physical quantity sensor, the control device increases the rotational speed ratio of the low-stage compression mechanism to the high-stage compression mechanism with increasing pressure of the low-pressure refrigerant. |
