Refrigerant cycle system

Abstract

A refrigerant cycle system includes: a first refrigerant circuit; a second refrigerant circuit independent of the first refrigerant circuit; a heat source-side unit that includes a first heat source-side heat exchange unit and a second heat source-side heat exchange unit; a first use-side unit that includes a first use-side heat exchanger; a first liquid refrigerant connection pipe and a first gas refrigerant connection pipe that connect the first use-side unit to the heat source-side unit; a second use-side unit that includes a second use-side heat exchanger; and a second liquid refrigerant connection pipe and a second gas refrigerant connection pipe that connect the second use-side unit to the heat source-side unit.

What is claimed is: 
     
         1 . A refrigerant cycle system comprising:
 a first refrigerant circuit;   a second refrigerant circuit independent of the first refrigerant circuit;   a heat source-side unit that comprises:
 a first heat source-side heat exchange unit; and 
 a second heat source-side heat exchange unit; 
   a first use-side unit that comprises:
 a first use-side heat exchanger; 
   a first liquid refrigerant connection pipe and a first gas refrigerant connection pipe that connect the first use-side unit to the heat source-side unit;   a second use-side unit that comprises:
 a second use-side heat exchanger; and 
   a second liquid refrigerant connection pipe and a second gas refrigerant connection pipe that connect the second use-side unit to the heat source-side unit, wherein   the first refrigerant circuit is constituted by:
 the first heat source-side heat exchange unit; 
 the first use-side heat exchanger; 
 the first liquid refrigerant connection pipe; and 
 the first gas refrigerant connection pipe, 
   the second refrigerant circuit is constituted by:
 the second heat source-side heat exchange unit; 
 the second use-side heat exchanger; 
 the second liquid refrigerant connection pipe; and 
 the second gas refrigerant connection pipe, and 
   a refrigerant classified by ISO817 as lower flammability (A2L) is disposed in each of the first refrigerant circuit and the second refrigerant circuit.   
     
     
         2 . The refrigerant cycle system according to  claim 1 , wherein
 the first heat source-side heat exchange unit further comprises first heat transfer tubes,   the first refrigerant circuit is further constituted by the first heat transfer tubes,   the second heat source-side heat exchange unit further comprises second heat transfer tubes,   the second refrigerant circuit is further constituted by the second heat transfer tubes, and   a heat source-side heat exchanger comprises:
 the first heat source-side heat exchange unit; 
 the second heat source-side heat exchange unit; and 
 a heat transfer fin through which both the first heat transfer tubes and the second heat transfer tubes penetrate. 
   
     
     
         3 . The refrigerant cycle system according to  claim 2 , wherein one or more of the second heat transfer tubes are disposed on a downwind side of any one of the first heat transfer tubes. 
     
     
         4 . The refrigerant cycle system according to  claim 3 , wherein half or more of the second heat transfer tubes are disposed on the downwind side of any one of the first heat transfer tubes. 
     
     
         5 . The refrigerant cycle system according to  claim 2 , wherein one or more of the second heat transfer tubes are disposed on a windward side of any one of the first heat transfer tubes. 
     
     
         6 . The refrigerant cycle system according to  claim 2 , wherein the heat source-side unit further comprises a heat source-side fan that supplies an air flow to the heat source-side heat exchanger. 
     
     
         7 . The refrigerant cycle system according to  claim 1 , wherein the refrigerant comprises R32. 
     
     
         8 . The refrigerant cycle system according to  claim 1 , wherein the refrigerant is a non-azeotropic mixed refrigerant. 
     
     
         9 . The refrigerant cycle system according to  claim 1 , wherein the refrigerant consists of one or more of R454A, R454B, and R454C. 
     
     
         10 . The refrigerant cycle system according to  claim 1 , wherein the first liquid refrigerant connection pipe and the second liquid refrigerant connection pipe have an outer diameter of 6.35 mm and an inner diameter of less than 4.75 mm. 
     
     
         11 . The refrigerant cycle system according to  claim 1 , wherein the first gas refrigerant connection pipe has a different diameter from the second gas refrigerant connection pipe has. 
     
     
         12 . The refrigerant cycle system according to  claim 11 , wherein the first liquid refrigerant connection pipe has a different diameter from the second liquid refrigerant connection pipe has. 
     
     
         13 . The refrigerant cycle system according to  claim 11 , wherein
 the first refrigerant circuit is further constituted by a third gas refrigerant connection pipe that has a different pipe diameter from the first gas refrigerant connection pipe has,   the second refrigerant circuit is further constituted by a fourth gas refrigerant connection pipe that has a different pipe diameter from the second gas refrigerant connection pipe has,   in the heat source-side unit,
 a shutoff valve of one of gas refrigerant connection pipes in the first refrigerant circuit that has a minimum pipe diameter is disposed lower than a shutoff valve of one of gas refrigerant connection pipes in the second refrigerant circuit that has a minimum pipe diameter, 
 a shutoff valve of one of the gas refrigerant connection pipes in the second refrigerant circuit that has a maximum pipe diameter is disposed lower than the shutoff valve of the one of the gas refrigerant connection pipes in the first refrigerant circuit that has the minimum pipe diameter, and 
 a shutoff valve of one of the gas refrigerant connection pipes in the first refrigerant circuit that has a maximum pipe diameter is disposed lower than the shutoff valve of the one of the gas refrigerant connection pipes in the second refrigerant circuit that has the maximum pipe diameter. 
   
     
     
         14 . The refrigerant cycle system according to  claim 11 , wherein
 the first refrigerant circuit is further constituted by a third gas refrigerant connection pipe that has a different pipe diameter from the first gas refrigerant connection pipe has,   the second refrigerant circuit is further constituted by a fourth gas refrigerant connection pipe that has a different pipe diameter from the second gas refrigerant connection pipe has,   in the heat source-side unit,
 a shutoff valve of one of gas refrigerant connection pipes in the second refrigerant circuit that has a minimum pipe diameter is disposed lower than a shutoff valve of one of gas refrigerant connection pipes in the first refrigerant circuit that has a minimum pipe diameter, 
 a shutoff valve of one of the gas refrigerant connection pipes in the second refrigerant circuit that has a maximum pipe diameter is disposed lower than the shutoff valve of the one of the gas refrigerant connection pipes in the second refrigerant circuit that has the minimum pipe diameter, and 
 a shutoff valve of one of the gas refrigerant connection pipes in the first refrigerant circuit that has a maximum pipe diameter is disposed lower than the shutoff valve of the one of the gas refrigerant connection pipes in the second refrigerant circuit that has the maximum pipe diameter. 
   
     
     
         15 . The refrigerant cycle system according to  claim 11 , wherein the first refrigerant circuit and the second refrigerant circuit are each constituted by a compressor that has an equal capacity. 
     
     
         16 . The refrigerant cycle system according to  claim 1 , wherein
 the first refrigerant circuit is further constituted by a first compressor,   the second refrigerant circuit is further constituted by a second compressor that has a smaller capacity than the first compressor has, and   the first gas refrigerant connection pipe has a larger pipe diameter than the second gas refrigerant connection pipe has.   
     
     
         17 . The refrigerant cycle system according to  claim 16 , wherein
 a sum of pipe diameters of all of gas refrigerant connection pipes in the first refrigerant circuit is greater than a sum of pipe diameters of all of gas refrigerant connection pipes in the second refrigerant circuit.   
     
     
         18 . The refrigerant cycle system according to  claim 1 , wherein
 the first refrigerant circuit is further constituted by a first compressor,   the second refrigerant circuit is further constituted by a second compressor that has a smaller capacity than the first compressor has,   the first gas refrigerant connection pipe has a different pipe diameter than the second gas refrigerant connection pipe has, and   a sum of pipe diameters of all of gas refrigerant connection pipes in the first refrigerant circuit is greater than a sum of pipe diameters of all of gas refrigerant connection pipes in the second refrigerant circuit.   
     
     
         19 . The refrigerant cycle system according to  claim 16 , wherein
 the heat source-side unit comprises a heat source-side heat exchanger that is common to the first refrigerant circuit and the second refrigerant circuit,   the heat source-side heat exchanger comprises:
 first heat transfer tubes belonging to the first refrigerant circuit; and 
 second heat transfer tubes belonging to the second refrigerant circuit, and 
   a number of the first heat transfer tubes is greater than a number of the second heat transfer tubes.   
     
     
         20 . The refrigerant cycle system according to  claim 19 , wherein in the heat source-side heat exchanger, one or more of the second heat transfer tubes are disposed on a downwind side of any one of the first heat transfer tubes. 
     
     
         21 . The refrigerant cycle system according to  claim 19 , further comprising a control unit that executes:
 an operation in a cooling cycle in the first refrigerant circuit, and   an operation in a heating cycle in the second refrigerant circuit simultaneously.