Refrigeration cycle apparatus

Abstract

A refrigeration cycle apparatus efficiently performs a cooling operation and a heating operation using a low-pressure refrigerant and a high-pressure refrigerant. A refrigeration cycle apparatus performs a heating operation by performing a two-stage refrigeration cycle, the two-stage refrigeration cycle including a use-side refrigeration cycle using a first refrigerant having 1 MPa or less at 30° C. and a heat-source-side refrigeration cycle using a second refrigerant having 1.5 MPa or Imre at 30° C., and performs a cooling operation by performing a single-stage refrigeration cycle using the first refrigerant.

1 . A refrigeration cycle apparatus, wherein the refrigeration cycle apparatus
 performs a heating operation by performing a two-stage refrigeration cycle, the two-stage refrigeration cycle including a use-side refrigeration cycle using a first refrigerant having 1 MPa or less at 30° C. and a heat-source-side refrigeration cycle using a second refrigerant having 1.5 MPa or more at 30° C., and   performs a cooling operation by performing a single-stage refrigeration cycle using the first refrigerant.   
     
     
         2 . The refrigeration cycle apparatus according to  claim 1 , comprising
 a cascade heat exchanger including a first cascade flow path through which the first refrigerant flows during the heating operation and a second cascade flow path that is independent of the first cascade flow path and through which the second refrigerant flows during the heating operation, the cascade heat exchanger being configured to exchange heat between the first refrigerant and the second refrigerant.   
     
     
         3 . The refrigeration cycle apparatus according to  claim 2 , further comprising
 a use heat exchanger in which the first refrigerant radiates heat during the heating operation, wherein   during the heating operation, the first refrigerant evaporates when passing through the first cascade flow path, and the second refrigerant radiates heat when passing through the second cascade flow path.   
     
     
         4 . The refrigeration cycle apparatus according to  claim 1 , comprising:
 a use heat exchanger in which the first refrigerant evaporates during the cooling operation; and   a first outdoor heat exchanger in which the first refrigerant radiates heat during the cooling operation.   
     
     
         5 . The refrigeration cycle apparatus according to  claim 1 , comprising
 a second outdoor heat exchanger in which the second refrigerant evaporates during the heating operation.   
     
     
         6 . A refrigeration cycle apparatus, wherein the refrigeration cycle apparatus
 performs a heating operation by performing a two-stage refrigeration cycle, the two-stage refrigeration cycle including a use-side refrigeration cycle using a first refrigerant having 1 MPa or less at 30° C. and a heat-source-side refrigeration cycle using a second refrigerant having 1.5 MPa or more at 30° C., and   performs a cooling operation by per ming a two-stage refrigerattion cycle, the two-stage refrigeration cycle including a use-side refrigeration cycle using the second refrigerant and a heat-source-side refrigeration cycle using the first refrigerant.   
     
     
         7 . The refrigeration cycle apparatus according to  claim 6 , comprising
 a cascade heat exchanger including a first cascade flow path through which the first refrigerant flows and a second cascade flow path that is independent of the first cascade flow path and through which the second refrigerant flows, the cascade heat exchanger being configured to exchange heat between the first refrigerant and the second refrigerant.   
     
     
         8 . The refrigeration cycle apparatus according to  claim 7 , further comprising
 a use heat exchanger including a first use flow path through which the first refrigerant flows and a second use flow path that is independent of the first use flow path and through which the second refrigerant flows.   
     
     
         9 . The refrigeration cycle apparatus according to  claim 8 , wherein
 during the heating operation, the first refrigerant evaporates when passing through the first cascade flow path, the second refrigerant radiates heat when passing through the second cascade flow path. and the first refrigerant radiates heat when passing through the first use flow path.   
     
     
         10 . The refrigeration cycle apparatus according to  claim 8 , wherein
 during the cooling operation, the first refrigerant evaporates when passing through the first cascade flow path, the second refrigerant radiates heat when passing through the second cascade flow path, and the second refrigerant evaporates when passing through the second use flow path.   
     
     
         11 . The refrigeration cycle apparatus according to  claim 8 , wherein
 during the cooling operation, the first refrigerant evaporates when passing through the first use flow path, and the second refrigerant evaporates when passing through the second use flow path.   
     
     
         12 . The refrigeration cycle apparatus according to  claim 8 , wherein
 during the heating operation, the first refrigerant radiates heat when passing through the first use flow path, and the second refrigerant radiates heat when passing through the second use flow path.   
     
     
         13 . The refrigeration cycle apparatus according to  claim 6 , comprising
 a first outdoor heat exchanger in which the first refrigerant radiates heat during the cooling operation.   
     
     
         14 . The refrigeration cycle apparatus according to  claim 6 , comprising
 a second outdoor heat exchanger in which the second refrigerant evaporates during the heating operation.   
     
     
         15 . The refrigeration cycle apparatus according to  claim 1 , wherein
 the first refrigerant includes at least one of R1234yf or R1234ze.   
     
     
         16 . The refrigeration cycle apparatus according to  claim 1 , wherein
 the second refrigerant includes carbon dioxide.   
     
     
         17 . The refrigeration cycle apparatus according to  claim 2 , comprising:
 a use heat exchanger in which the first refrigerant evaporates during the cooling operation; and   a first outdoor heat exchanger in which the first refrigerant radiates heat during the cooling operation.   
     
     
         18 . The refrigeration cycle apparatus according to  claim 3 , comprising:
 a use heat exchanger in which the first refrigerant evaporates during the cooling operation; and   a first outdoor heat exchanger in which the first refrigerant radiates heat during the cooling operation.   
     
     
         19 . The refrigeration cycle apparatus according to  claim 2 , comprising
 a second outdoor heat exchanger in which the second refrigerant evaporates during the heating operation.   
     
     
         20 . The refrigeration cycle apparatus according to  claim 3 , comprising
 a second outdoor heat exchanger in which the second refrigerant evaporates during the heating operation.