Refrigeration apparatus

Abstract

In an air-conditioning apparatus, refrigerant flows sequentially through a compressor, an outdoor heat exchanger, expansion mechanisms, and an indoor heat exchanger during a cooling operation, and refrigerant flows sequentially through the compressor, the indoor heat exchanger, the expansion mechanisms, and the outdoor heat exchanger during a heating operation. Capacity of the outdoor heat exchanger is 30% to 90% of the indoor heat exchanger. The expansion mechanisms include an upstream-side and downstream-side expansion mechanisms depressurizing refrigerant from high to intermediate pressure, and from intermediate to low pressure in the refrigerant cycle, respectively. The refrigerant is R32. A refrigerant storage tank that stores the intermediate pressure refrigerant is provided between the upstream-side and downstream side expansion mechanisms. The refrigerant storage tank stores an excess refrigerant produced during the cooling operation due to capacity of the outdoor heat exchanger relative the indoor heat exchanger.

1 . A refrigeration apparatus in which a refrigerant flows sequentially through a compressor, an outdoor heat exchanger, expansion mechanisms, and an indoor heat exchanger during a cooling operation, and the refrigerant flows sequentially through the compressor, the indoor heat exchanger, the expansion mechanisms, and the outdoor heat exchanger during a heating operation;
 the indoor heat exchanger being a cross-fin heat exchanger and the outdoor heat exchanger being a stacked heat exchanger, and a capacity ratio of the outdoor heat, exchanger to the indoor heat exchanger is 0.3 to 0.9;   the expansion mechanisms including
 an upstream-side expansion mechanism configured to depressurize the refrigerant from a high pressure in a refrigerant cycle to an intermediate pressure in the refrigerant cycle and 
 a downstream-side expansion mechanism configured to depressurize the refrigerant that has been depressurized in the upstream-side expansion mechanism from the intermediate pressure in the refrigerant cycle to a low pressure in the refrigerant cycle; 
   the outdoor heat exchanger, the upstream-side expansion mechanism and the downstream-side expansion mechanism being provided in an outdoor unit, the indoor heat exchanger being provided in an indoor unit, and the outdoor unit and the indoor unit being connected via a liquid refrigerant communication tube;   the refrigerant being R32;   a refrigerant storage tank configured and arranged to store the refrigerant depressurized to the intermediate pressure in the refrigerant cycle by the upstream-side expansion mechanism being provided between the upstream-side expansion mechanism and the downstream -side expansion mechanism; and   the refrigerant storage tank storing an excess refrigerant produced during the cooling operation due to a capacity of the outdoor heat exchanger being less than a capacity of the indoor heat exchanger.   
     
     
         2 . A refrigeration apparatus in which a refrigerant flows sequentially through a compressor, an outdoor heat exchanger, expansion mechanisms, and an indoor heat exchanger during a cooling operation, and the refrigerant flows sequentially through the compressor, the indoor heat exchanger, the expansion mechanisms, and the outdoor heat exchanger during a heating operation;
 a capacity of the outdoor heat exchanger being 30% to 90% of a capacity of the indoor heat exchanger;   the expansion mechanisms including
 an upstream-side expansion mechanism, configured to depressurize the refrigerant from a high pressure in a refrigerant cycle to an intermediate pressure in the refrigerant cycle and 
 a downstream-side expansion mechanism configured to depressurize the refrigerant that has been depressurized in the upstream-side expansion mechanism from the intermediate pressure in the refrigerant cycle to a low pressure in the refrigerant cycle; 
   the outdoor heat exchanger, the upstream-side expansion mechanism and the downstream-side expansion mechanism being provided in an outdoor unit, the indoor heat exchanger being provided in an indoor unit, and the outdoor unit and the indoor unit being connected via a liquid refrigerant communication tube;   the refrigerant being R32;   a refrigerant storage tank configured and arranged to store the refrigerant depressurized to the intermediate pressure in the refrigerant cycle by the upstream-side expansion mechanism being provided between the upstream-side expansion mechanism and the downstream-side expansion mechanism; and   the refrigerant storage tank boring an excess refrigerant produced during the cooling operation due to a capacity of the outdoor heat exchanger being less than a capacity of the indoor heat exchanger.   
     
     
         3 . The refrigeration apparatus according to  claim 2 , wherein
 the outdoor heat exchanger is a stacked heal exchanger having a plurality of flat lubes arrayed so as to be superposed set apart by gaps, and fins sandwiched between adjacent flat tubes.   
     
     
         4 . The refrigeration apparatus according to  claim 2 , wherein
 the outdoor heat exchanger is a stacked heat exchanger having a plurality of flat tubes arrayed so as to be superposed set apart by gaps, and fins having notches formed therein where the flat tubes are inserted.   
     
     
         5 . The refrigeration apparatus according to  claim 2 , wherein
 the outdoor heat exchanger is a stacked heat exchanger having flat tubes molded into serpentine shapes, and fins inserted between mutually adjacent surfaces of the flat tubes.   
     
     
         6 . The refrigeration apparatus according to  claim 2 , wherein
 the outdoor heat exchanger and the indoor heat exchanger are cross-fin heat exchangers; and   a diameter of heat transfer tubes in the outdoor heat exchanger is less than a diameter of heat transfer tubes in the indoor heat exchanger.   
     
     
         7 . The refrigeration apparatus according to  claim 2 , further comprising
 a bypass tube configured and arranged to lead a gas component of the refrigerant accumulated in the refrigerant storage tank to the compressor or to a refrigerant tube on an intake side of the compressor.   
     
     
         8 . The refrigeration apparatus according to  claim 7 , wherein
 the bypass tube has a flow rate adjustment mechanism.   
     
     
         9 . The refrigeration apparatus according to  claim 2 , wherein
 the refrigerant storage tank is a gas-liquid separator.   
     
     
         10 . The refrigeration apparatus according to  claim 1 , wherein
 the outdoor heat exchanger is a stacked heat exchanger having a plurality of flat tubes arrayed so as to be superposed set apart by gaps, and fins sandwiched between adjacent flat tubes.   
     
     
         11 . The refrigeration apparatus according to  claim 1 , wherein
 the outdoor heat exchanger is a slacked heat exchanger having a plurality of flat tubes arrayed so as to be superposed set apart by gaps, and fins having notches formed therein where the flat tubes are inserted.   
     
     
         12 . The refrigeration apparatus according to  claim 1 , wherein
 the outdoor heat exchanger is a stacked heat exchanger having flat tubes molded into serpentine shapes, and fins inserted between mutually adjacent surfaces of the flat tubes.   
     
     
         13 . The refrigeration apparatus according to  claim 1 , further comprising
 a bypass tube configured and arranged to lead a gas component of the refrigerant accumulated in the refrigerant storage tank to the compressor or to a refrigerant tube on an intake side of the compressor.   
     
     
         14 . The refrigeration apparatus according to  claim 13 , wherein the bypass tube has a flow rate adjustment mechanism. 
     
     
         15 . The refrigeration apparatus according to  claim 1 , wherein the refrigerant storage tank is a gas-liquid separator.