Binary refrigerating apparatus

Abstract

A binary refrigerating apparatus employs a refrigerant composition that has a small global-warming potential (GWP) to be earth friendly, can be used as a refrigerant capable of achieving a low temperature of −80° C., and is excellent in refrigerating capacity and other performance. A refrigerant composition used as a low-temperature-side refrigerant is a refrigerant mixture including a non-azeotropic mixture in which 20% by mass or less of carbon dioxide (R744) is mixed to difluoroethylene (R1132a). A refrigerant composition used as a high-temperature-side refrigerant is a combination of: a non-azeotropic mixture comprising the refrigerant group of difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a) and 1,1,3-trifluoro ethane (R143a); and 1,1,1,2,3-pentafluoropentene (HFO-1234ze), having a global-warming potential (GWP) of 1500 or less.

1 . A binary refrigerating apparatus comprising a high-temperature-side refrigeration circuit and a low-temperature-side refrigeration circuit, which achieves a refrigerating capacity of −80° C. or lower by condensing a refrigerant in the low-temperature-side refrigeration circuit with a refrigerant passing through a cascade condenser in the high-temperature-side refrigeration circuit,
 wherein a refrigerant composition containing difluoroethylene (R1132a) and hexafluoroethane (R116) is used as the refrigerant in the low-temperature-side refrigeration circuit, so that an evaporation temperature reaches a temperature lower than both boiling points of difluoroethylene (R1132a) and hexafluoroethane (R116). 
 
     
     
         2 . A binary refrigerating apparatus comprising a high-temperature-side refrigeration circuit and a low-temperature-side refrigeration circuit, which achieves a refrigerating capacity of −80° C. or lower by condensing a refrigerant in the low-temperature-side refrigeration circuit with a refrigerant passing through a cascade condenser in the high-temperature-side refrigeration circuit,
 wherein a refrigerant composition containing difluoroethylene (R1132a) and more than 0% by mass and 20% by mass or less of carbon dioxide (R744) is used as the refrigerant in the low-temperature-side refrigeration circuit, so that an evaporation temperature reaches a temperature lower than both boiling points of difluoroethylene (R1132a) and carbon dioxide (R744). 
 
     
     
         3 . The binary refrigerating apparatus according to  claim 1 , wherein a refrigerant composition in which carbon dioxide (R744) is further mixed is used as the refrigerant in the low-temperature-side refrigeration circuit, so that an evaporation temperature reaches a temperature lower than any boiling points of difluoroethylene (R1132a), hexafluoroethane (R116), and carbon dioxide (R744). 
     
     
         4 . The binary refrigerating apparatus according to  claim 2 , wherein hexafluoroethane (R116) is further mixed as the refrigerant in the low-temperature-side refrigeration circuit. 
     
     
         5 . The binary refrigerating apparatus according to  claim 4 , wherein a refrigerant composition in which difluoroethylene (R1132a)/hexafluoroethane (R116)/carbon dioxide (R744)=27.6 to 29.2% by mass/56.8 to 68.4% by mass/4.0 to 14.0% by mass are mixed is used as the refrigerant in the low-temperature-side refrigeration circuit. 
     
     
         6 . The binary refrigerating apparatus according to  claim 4 , wherein a refrigerant composition in which difluoroethylene (R1132a)/hexafluoroethane (R116)/carbon dioxide (R744)=54.8 to 58.3% by mass/25.2 to 35.7% by mass/8.0 to 18.0% by mass are mixed is used as the refrigerant in the low-temperature-side refrigeration circuit. 
     
     
         7 . The binary refrigerating apparatus according to  claim 1 , wherein a refrigerant composition in which n-pentane is mixed in a ratio of 14% by mass or less with respect to the total mass of the refrigerant composition in the low-temperature-side refrigeration circuit is used. 
     
     
         8 . The binary refrigerating apparatus according to  claim 1 , wherein a refrigerant composition in which propane (R290) is mixed in a ratio of 14% by mass or less with respect to the total mass of the refrigerant composition in the low-temperature-side refrigeration circuit is used. 
     
     
         9 . The binary refrigerating apparatus according to  claim 1 , wherein a refrigerant composition, containing a non-azeotropic mixture comprising the refrigerant group of difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), and 1,1,3-trifluoroethane (R143a), and 1,1,1,2,3-pentafluoropentene (HFO-1234ze), and having a Global-warming potential (GWP) of 1500 or less, is used as the refrigerant in the high-temperature-side refrigeration circuit. 
     
     
         10 . The binary refrigerating apparatus according to  claim 1 , wherein a refrigerant composition, containing a non-azeotropic mixture comprising the refrigerant group of difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), and 1,1,3-trifluoroethane (R143a), and 1,1,1,2-tetrafluoropentene (HFO-1234yf), and having a Global-warming potential (GWP) of 1500 or less, is used as the refrigerant in the high-temperature-side refrigeration circuit. 
     
     
         11 . The binary refrigerating apparatus according to  claim 2 , wherein a refrigerant composition in which n-pentane is mixed in a ratio of 14% by mass or less with respect to the total mass of the refrigerant composition in the low-temperature-side refrigeration circuit is used. 
     
     
         12 . The binary refrigerating apparatus according to  claim 2 , wherein a refrigerant composition in which propane (R290) is mixed in a ratio of 14% by mass or less with respect to the total mass of the refrigerant composition in the low-temperature-side refrigeration circuit is used. 
     
     
         13 . The binary refrigerating apparatus according to  claim 2 , wherein a refrigerant composition, containing a non-azeotropic mixture comprising the refrigerant group of difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), and 1,1,3-trifluoroethane (R143a), and 1,1,1,2,3-pentafluoropentene (HFO-1234ze), and having a Global-warming potential (GWP) of 1500 or less, is used as the refrigerant in the high-temperature-side refrigeration circuit. 
     
     
         14 . The binary refrigerating apparatus according to  claim 2 , wherein a refrigerant composition, containing a non-azeotropic mixture comprising the refrigerant group of difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), and 1,1,3-trifluoroethane (R143a), and 1,1,1,2-tetrafluoropentene (HFO-1234yf), and having a Global-warming potential (GWP) of 1500 or less, is used as the refrigerant in the high-temperature-side refrigeration circuit.