Refrigeration System

Abstract

A refrigerant circuit ( 20 ) is provided with an intermediate pressure heat exchanger ( 40 ) and a gas/liquid separator ( 51 ). In a cooling mode, a part of refrigerant condensed in an outdoor heat exchanger ( 36 ) flows into injection piping ( 43 ). The refrigerant admitted into the injection piping ( 43 ) is pressure reduced down to an intermediate pressure during its passage through an injection expansion valve ( 44 ), evaporates in the intermediate pressure heat exchanger ( 40 ), and is supplied to an intermediate pressure port ( 32 ) of a compressor ( 31 ). In a heating mode, refrigerant condensed in an indoor heat exchanger ( 71 ) is pressure reduced down to an intermediate pressure during its passage through an indoor expansion valve ( 72 ) and then flows into the gas/liquid separator ( 51 ). And, the intermediate pressure gas refrigerant within the gas/liquid separator ( 51 ) is supplied to the intermediate pressure port ( 32 ) of the compressor ( 31 ).

1 . A refrigeration system comprising a refrigerant circuit ( 20 ) wherein the refrigerant circuit ( 20 ) includes a compressor ( 31 ,  34 ), a heat source side heat exchanger ( 36 ), and a utilization side heat exchanger ( 71 ) which are connected to perform a refrigerating cycle, and wherein the refrigerant circuit ( 20 ) is selectively operable either in a cooling mode in which the heat source side heat exchanger ( 36 ) becomes a condenser and the utilization side heat exchanger ( 71 ) becomes an evaporator or a heating mode in which the utilization side heat exchanger ( 71 ) becomes a condenser and the heat source side heat exchanger ( 36 ) becomes an evaporator,
 wherein the refrigerant circuit ( 20 ) further includes:
 an injection passageway ( 43 ) through which to supply to the compressor ( 31 ,  34 ) intermediate pressure refrigerant resulting from pressure reducing a part of high pressure liquid refrigerant, 
 an intermediate pressure heat exchanger ( 40 ) in which intermediate pressure refrigerant flowing through the injection passageway ( 43 ) towards the compressor ( 31 ,  34 ) exchanges heat with high pressure liquid refrigerant and evaporates, and 
 a gas/liquid separator ( 51 ) in which intermediate pressure refrigerant resulting from pressure reducing high pressure liquid refrigerant is separated into liquid refrigerant and gas refrigerant, and 
   wherein the refrigerant circuit ( 20 ) is configured such that its refrigerant circulation path is selectively changeable between the cooling mode during which gas refrigerant of intermediate pressure flowing through the injection passageway ( 43 ) is supplied to the compressor ( 31 ,  34 ) and the heating mode during which gas refrigerant of intermediate pressure flowing out of the gas/liquid separator ( 51 ) is supplied to the compressor ( 31 ,  34 ).   
   
   
       2 . The refrigeration system of  claim 1 ,
 wherein the refrigerant circuit ( 20 ) is formed by connecting, by interconnecting piping ( 21 ,  22 ), a heat source side circuit ( 30 ) in which the compressor ( 31 ,  34 ) and the heat source side heat exchanger ( 36 ) are disposed and a utilization side circuit ( 70 ) in which the utilization side heat exchanger ( 71 ) is disposed, and   wherein the injection passageway ( 43 ), the intermediate pressure heat exchanger ( 40 ), and the gas/liquid separator ( 51 ) are disposed in the heat source side circuit ( 30 ).   
   
   
       3 . The refrigeration system of  claim 1 ,
 wherein the gas/liquid separator ( 51 ) is formed by a container-shaped member ( 65 ) which is arranged at a position in the refrigerant circuit ( 20 ), which position is located, during the cooling mode, downstream of the heat source side heat exchanger ( 36 ) and is located, during the heating mode, downstream of the utilization side heat exchanger ( 71 ), and   wherein the intermediate pressure heat exchanger ( 40 ) is formed by a heat exchange member ( 66 ) which is housed in the inside of the container-shaped member ( 65 ) and in which intermediate pressure refrigerant flowing through the injection passageway ( 43 ) exchanges heat with liquid refrigerant within the container-shaped member ( 65 ).   
   
   
       4 . The refrigeration system of  claim 1 , wherein a supercooling heat exchanger ( 60 ), configured to cool high pressure liquid refrigerant by heat exchange with low pressure refrigerant resulting from pressure reducing a part of the high pressure liquid refrigerant, is arranged at a position in the refrigerant circuit ( 20 ), which position is located, during the cooling mode, downstream of the intermediate pressure heat exchanger ( 40 ). 
   
   
       5 . The refrigeration system of  claim 1 ,
 wherein a single-stage compression refrigerating cycle is performed in the refrigerant circuit ( 20 ), and   wherein the compressor ( 31 ) is configured such that gas refrigerant of intermediate pressure flows into a compression chamber being in the process of compression.   
   
   
       6 . The refrigeration system of  claim 1 ,
 wherein in the refrigerant circuit ( 20 ), a lower stage compressor ( 33 ) and a higher stage compressor ( 34 ) are connected together in series to perform a two-stage compression refrigerating cycle, and   wherein the refrigerant circuit ( 20 ) is configured such that gas refrigerant of intermediate pressure is supplied to a suction side of the higher stage compressor ( 34 ).