Refrigeration apparatus

Abstract

A refrigeration apparatus uses a refrigerant that operates in a supercritical range, and includes a compression mechanism, a heat source-side heat exchanger, an expansion mechanism, a usage-side heat exchanger, an intercooler and an intermediate oil separation mechanism. The compression mechanism has a plurality of compression elements, and is configured and arranged so that refrigerant discharged from a first-stage compression element is sequentially compressed by a second-stage compression element. The intercooler is configured and arranged to cool refrigerant flowing through an intermediate refrigerant tube that draws refrigerant discharged from the first-stage compression element into the second-stage compression element. The intermediate oil separation mechanism is configured and arranged to separate a refrigeration oil from the refrigerant discharged from the first-stage compression element. The intermediate oil separation mechanism is arranged at a section of the intermediate refrigerant tube between the first-stage compression element and an inlet of the intercooler.

1 . A refrigeration apparatus which uses a refrigerant that operates in a supercritical range, the refrigeration apparatus comprising:
 a compression mechanism having a plurality of compression elements, the compression mechanism being configured and arranged so that refrigerant discharged from a first-stage compression element of the plurality of compression elements is sequentially compressed by a second-stage compression element;   a heat source-side heat exchanger;   an expansion mechanism configured and arranged to depressurize the refrigerant;   a usage-side heat exchanger;   an intercooler configured and arranged to cool refrigerant flowing through an intermediate refrigerant tube that draws refrigerant discharged from the first-stage compression element into the second-stage compression element; and   an intermediate oil separation mechanism configured and arranged to separate a refrigeration oil from the refrigerant, the refrigeration oil accompanying the refrigerant discharged from the first-stage compression element, and the intermediate oil separation mechanism being arranged at a section of the intermediate refrigerant tube between the first-stage compression element and an inlet of the intercooler.   
     
     
         2 . The refrigeration apparatus according to  claim 1 , wherein
 the intermediate oil separation mechanism has
 an intermediate oil separator configured and arranged to separate the refrigeration oil from the refrigerant discharged from the first-stage compression element, and 
 an intermediate oil return tube configured and arranged to return the refrigeration oil separated from the refrigerant to the compression mechanism, the intermediate oil return tube being connected to the intermediate oil separator. 
   
     
     
         3 . The refrigeration apparatus according to  claim 1 , wherein
 the intermediate oil separation mechanism has
 a header arranged at the inlet of the intercooler, and 
 an intermediate oil return tube for connecting a lower end of the header to the compression mechanism. 
   
     
     
         4 . The refrigeration apparatus according to  claim 1 , wherein
 the refrigerant that operates in the supercritical range is carbon dioxide.   
     
     
         5 . The refrigeration apparatus according to  claim 2 , wherein the refrigerant that operates in the supercritical range is carbon dioxide. 
     
     
         6 . The refrigeration apparatus according to  claim 3 , wherein the refrigerant that operates in the supercritical range is carbon dioxide.