Refrigerating apparatus

Abstract

In a refrigerant circuit ( 5 ) of an air conditioner ( 1 ), a single-stage compression refrigeration cycle is performed. In the refrigerant circuit ( 5 ), a second heat exchanger ( 40 ) is provided downstream a first heat exchanger ( 30 ). In the first heat exchanger ( 30 ), high-pressure refrigerant of a high-pressure flow path ( 31 ) is cooled by exchanging heat with first intermediate-pressure refrigerant of an intermediate-pressure flow path ( 32 ). First intermediate-pressure gas refrigerant generated in the first heat exchanger ( 30 ) is supplied to a first compression mechanism ( 71 ). Second intermediate-pressure refrigerant having a pressure lower than that of the first intermediate-pressure refrigerant is supplied to an intermediate-pressure flow path ( 42 ) of the second heat exchanger ( 40 ). In the second heat exchanger ( 40 ), high-pressure refrigerant of a high-pressure flow path ( 41 ) is further cooled by exchanging heat with the second intermediate-pressure refrigerant of the intermediate-pressure flow path ( 42 ). Second intermediate-pressure gas refrigerant generated in the second heat exchanger ( 40 ) is supplied to a second compression mechanism ( 72 ).

1 . A refrigerating apparatus, comprising:
 a refrigerant circuit including a radiator and an evaporator and performing a refrigeration cycle; and   a first compression mechanism and a second compression mechanism each including a compression chamber,   wherein each of the first compression mechanism and the second compression mechanism sucks low-pressure refrigerant into the compression chamber, and compresses the low-pressure refrigerant to a high pressure level, and   the refrigerant circuit includes   an enthalpy reducing unit for reducing an enthalpy of refrigerant flowing from the radiator to the evaporator by generating first intermediate-pressure gas refrigerant and second intermediate-pressure gas refrigerant having a pressure lower than that of the first intermediate-pressure gas refrigerant,   a first injection path for supplying the first intermediate-pressure gas refrigerant generated in the enthalpy reducing unit to the compression chamber of the first compression mechanism in the middle of a compression process, and   a second injection path for supplying the second intermediate-pressure gas refrigerant generated in the enthalpy reducing unit to the compression chamber of the second compression mechanism in the middle of a compression process.   
     
     
         2 . A refrigerating apparatus, comprising:
 a refrigerant circuit including a radiator and an evaporator and performing a refrigeration cycle; and   a first compression mechanism and a second compression mechanism each including a compression chamber,   wherein the second compression mechanism sucks low-pressure refrigerant into the compression chamber and compresses the low-pressure refrigerant, and the first compression mechanism sucks the refrigerant discharged from the second compression mechanism into the compression chamber and compresses the refrigerant, and   the refrigerant circuit includes   an enthalpy reducing unit for reducing an enthalpy of refrigerant flowing from the radiator to the evaporator by generating first intermediate-pressure gas refrigerant and second intermediate-pressure gas refrigerant having a pressure lower than that of the first intermediate-pressure gas refrigerant,   a second injection path for supplying the second intermediate-pressure gas refrigerant generated in the enthalpy reducing unit to the compression chamber of the second compression mechanism in the middle of a compression process, and   a first injection path for supplying the first intermediate-pressure gas refrigerant generated in the enthalpy reducing unit to the compression chamber of the first compression mechanism in the middle of a compression process, or to an inlet side of the first compression mechanism.   
     
     
         3 . A refrigerating apparatus, comprising:
 a refrigerant circuit including a radiator and an evaporator and performing a refrigeration cycle; and   a first compression mechanism and a second compression mechanism each including a compression chamber,   wherein the second compression mechanism sucks low-pressure refrigerant into the compression chamber and compresses the low-pressure refrigerant, and the first compression mechanism sucks the refrigerant discharged from the second compression mechanism into the compression chamber and compresses the refrigerant, and   the refrigerant circuit includes   an enthalpy reducing unit for reducing an enthalpy of refrigerant flowing from the radiator to the evaporator by generating first intermediate-pressure gas refrigerant and second intermediate-pressure gas refrigerant having a pressure lower than that of the first intermediate-pressure gas refrigerant,   a second injection path for supplying the second intermediate-pressure gas refrigerant generated in the enthalpy reducing unit to an inlet side of the first compression mechanism, and   a first injection path for supplying the first intermediate-pressure gas refrigerant generated in the enthalpy reducing unit to the compression chamber of the first compression mechanism in the middle of a compression process.   
     
     
         4 . The refrigerating apparatus of any one of  claims 1 - 3 , wherein
 in the refrigerant circuit, a portion of the refrigerant circuit from an outlet of the radiator to an inlet of the evaporator forms a main path, and   the enthalpy reducing unit includes   a branched path which is connected to the main path and into which a part of refrigerant flowing through the main path flows,   an expansion mechanism for expanding the refrigerant flowing into the branched path to generate first intermediate-pressure refrigerant and second intermediate-pressure refrigerant having a pressure lower than that of the first intermediate-pressure refrigerant,   a first heat exchanger which is connected to the main path downstream the radiator to exchange heat between the refrigerant flowing through the main path and the first intermediate-pressure refrigerant, which cools the refrigerant flowing through the main path, and which generates the first intermediate-pressure gas refrigerant by evaporating the first intermediate-pressure refrigerant, and   a second heat exchanger which is connected to the main path between the first heat exchanger and the evaporator to exchange heat between the refrigerant flowing through the main path and the second intermediate-pressure refrigerant, which cools the refrigerant flowing through the main path, and which generates the second intermediate-pressure gas refrigerant by evaporating the second intermediate-pressure refrigerant.   
     
     
         5 . The refrigerating apparatus of  claim 4 , wherein
 the branched path of the enthalpy reducing unit includes   a first branched pipe which is connected to the main path between the radiator and the first heat exchanger, and which supplies refrigerant flowing from the main path to the first heat exchanger, and   a second branched pipe which is connected to the main path between the first heat exchanger and the second heat exchanger, and which supplies the refrigerant flowing from the main path to the second heat exchanger, and   the expansion mechanism of the enthalpy reducing unit includes   a first expansion valve which is provided in the first branched pipe, and which generates the first intermediate-pressure refrigerant by expanding refrigerant flowing into the first branched pipe, and   a second expansion valve which is provided in the second branched pipe, and which generates the second intermediate-pressure refrigerant by expanding refrigerant flowing into the second branched pipe.   
     
     
         6 . The refrigerating apparatus of  claim 4 , wherein
 the branched path of the enthalpy reducing unit includes   a first branched pipe which is connected to the main path between the radiator and the first heat exchanger, and which supplies refrigerant flowing from the main path to the first heat exchanger, and   a second branched pipe which is connected to the first branched pipe, and which supplies refrigerant flowing from the first branched pipe to the second heat exchanger, and   the expansion mechanism of the enthalpy reducing unit includes   a first expansion valve which is provided in the first branched pipe, and which generates the first intermediate-pressure refrigerant by expanding refrigerant flowing into the first branched pipe, and   a second expansion valve which is provided in the second branched pipe, and which generates the second intermediate-pressure refrigerant by expanding refrigerant flowing into the second branched pipe.   
     
     
         7 . The refrigerating apparatus of any one of  claims 1 - 3 , wherein
 the enthalpy reducing unit includes   a first expansion valve for expanding high-pressure refrigerant flowing out from the radiator,   a first gas-liquid separator for separating the refrigerant flowing out from the first expansion valve in a gas-liquid two-phase state into gas refrigerant and liquid refrigerant, and supplying the gas refrigerant to the first injection path as the first intermediate-pressure gas refrigerant,   a second expansion valve for expanding the liquid refrigerant flowing out from the first gas-liquid separator, and   a second gas-liquid separator for separating the refrigerant flowing out from the second expansion valve in the gas-liquid two-phase state into gas refrigerant and liquid refrigerant, supplying the gas refrigerant to the second injection path as the second intermediate-pressure gas refrigerant, and supplying the liquid refrigerant to the evaporator.   
     
     
         8 . The refrigerating apparatus of any one of  claims 1 - 3 , wherein
 the first compression mechanism and the second compression mechanism are provided in a single compressor, and   the compressor includes a single drive shaft engaged with both of the first compression mechanism and the second compression mechanism.   
     
     
         9 . The refrigerating apparatus of any one of  claims 1 - 3 , wherein
 the first compression mechanism is provided in a first compressor, and the second compression mechanism is provided in a second compressor, and   the first compressor includes a drive shaft engaged with the first compression mechanism, and the second compressor includes a drive shaft engaged with the second compression mechanism.