Refrigerating cycle device

Abstract

A refrigerating cycle apparatus including a compressor of compressing carbon dioxide (CO 2 ) refrigerant, a radiator of cooling the refrigerant pressurized by the compressor, a pressure reducing valve that is arranged more downstream of the radiator along the refrigerant flow and depressurizes and expands the cooled refrigerant, and an evaporator that heats the refrigerant depressurized by the pressure reducing valve, wherein the refrigerant flow path of the radiator and/or said evaporator is has a diameter of 1 mm or less; and a refrigeration lubricant of which main component is a polar oil miscible with the CO 2 refrigerant is utilized.

1 . A refrigerating cycle apparatus, comprising a compressor of compressing carbon dioxide (CO 2 ) refrigerant, a radiator of cooling the refrigerant pressurized by said compressor, a pressure reducing valve that is arranged more downstream of said radiator along the refrigerant flow and depressurizes and expands the cooled refrigerant, and an evaporator that heats the refrigerant depressurized by said pressure reducing valve, 
 wherein the refrigerant flow path of said radiator and/or said evaporator has a diameter of about 1 mm or less; and    refrigeration lubricant of which main component is a polar oil miscible with said CO 2  refrigerant is utilized.    
     
     
         2 . The refrigerating cycle apparatus according to  claim 1 , wherein said refrigerant flow path is some thin through-holes formed in flat tubes.  
     
     
         3 . The refrigerating cycle apparatus according to  claim 1 , wherein an ester oil, an ether oil, polyalkyleneglycol oil, polycarbonate oil, or a mixed oil thereof is used as said refrigeration lubricant.  
     
     
         4 . The refrigerating cycle apparatus according to  claim 1 , wherein the moisture content contained in said refrigeration lubricant is 100 ppm or less.  
     
     
         5 . The refrigerating cycle apparatus according to  claim 2 , wherein said thin through-holes are thin holes with inside grooves in which grooves are formed on the inner surface.  
     
     
         6 . The refrigerating cycle apparatus according to  claim 5 , wherein the groove shape of said through-holes with inside grooves is trapezoidal.