Hermetic compressor and refrigeration system

Abstract

In a hermetic compressor, aggression to an organic material is low by using a refrigeration oil using, as a base oil, an alicyclic multivalent carboxylic acid ester compound and made of an alicyclic multivalent carboxylic acid ester compound having at least two ester groups, the at least two ester groups being bound to carbon atoms adjacent to each other on an alicyclic ring. The ratio of hydrocarbon radicals in which carbon number is 4 or less among hydrocarbon radicals bound to the at least two ester groups is 15% by weight or less.

1 . A hermetic compressor comprising:
 a hermetic container;   a refrigeration oil stored in the hermetic container;   an electric element housed in the hermetic container;   a compression element driven by the electric element; and   a refrigerant compressed by the compression element,   wherein the refrigerant contains a hydrofluorocarbon as a main component and has a critical temperature of 40 degrees centigrade or higher,   a base oil of the refrigeration oil is an alicyclic multivalent carboxylic acid ester compound having a kinetic viscosity of 2 to 70 cSt at 40 degrees centigrade and 1 to 9 cSt at 100 degrees centigrade and whose temperature of separation from the refrigerant is −35 degrees centigrade or lower at a lower critical temperature and 70 degrees centigrade or higher at an upper critical temperature,   the alicyclic multivalent carboxylic acid ester compound has at least two ester groups, the at least two ester groups are bound to carbon atoms adjacent to each other on an alicyclic ring and, further, the ratio of hydrocarbon radicals in which carbon number is 4 or less among hydrocarbon radicals bound to the at least two ester groups is 15% by weight or less.   
   
   
       2 . The hermetic compressor according to  claim 1 , wherein the refrigeration oil is obtained by mixing monoester oil in the range of 5 to 30% by weight. 
   
   
       3 . The hermetic compressor according to  claim 1 , wherein the electric element comprises:
 an enameled copper wire; and   an insulating film,   the enameled copper wire has one of an upper-layer polyamide-imide/lower-layer polyester imide copper wire and upper-layer polyamide-imide/lower-layer modified polyester copper wire, and   the insulating film is made of any one of polyethylene terephthalate, polyethylene naphthalate, polyamide-imide coat polyester, polyphenylene sulfide, and polyether ether ketone.   
   
   
       4 . The hermetic compressor according to  claim 1 , wherein the compression element has a suction muffler, and
 the suction muffler is made of any one of low oligomer polyethylene terephthalate, polyethylene terephthalate containing no paraffin, polyethylene naphthalate, polyamide-imide coat polyester, polyphenylene sulfide, and polyether ether ketone.   
   
   
       5 . The hermetic compressor according to  claim 1 , further comprising a rubber part in the hermetic container, and
 the rubber part is made of any of nitrile rubber, hydrogenerated nitrile rubber, and fluororubber.   
   
   
       6 . The hermetic compressor according to  claim 1 , wherein the compression element has a sliding part, and
 the sliding part is made of any one of combination of gray cast irons, combination of the gray cast iron and a spheroidal graphite cast iron, combination of the gray cast iron and a sintered metal, combination of the gray cast iron and a high-silicon aluminum material, combination of the spheroidal graphite cast iron and the high-silicon aluminum, combination of the high-silicon aluminum material and a chrome molybdenum steel material subjected to a carburizing process, and combination of the high-silicon aluminum material and the chrome molybdenum steel material subjected to a nitriding process.   
   
   
       7 . The hermetic compressor according to  claim 1 , wherein the refrigeration oil contains a foaming agent. 
   
   
       8 . The hermetic compressor according to  claim 1 , wherein the refrigeration oil contains an antioxidant agent. 
   
   
       9 . The hermetic compressor according to  claim 1 , wherein the refrigeration oil contains an extreme-pressure additive agent. 
   
   
       10 . A refrigeration system comprising:
 the hermetic compressor according to  claim 1 ;   an evaporator;   a condenser; and   an expansion mechanism.   
   
   
       11 . The refrigeration system according to  claim 10 , wherein the refrigeration oil is mixed with ester oil, and
 the ester oil is obtained by a reaction between an aliphatic alcohol and a fatty acid whose temperature of two-phase separation from a hydrofluorocarbon refrigerant is −35 degrees centigrade or lower at a lower critical temperature and 70 degrees centigrade or higher at an upper critical temperature.   
   
   
       12 . The refrigeration system according to  claim 11 , wherein the refrigeration oil is mixed with 1 to 50% by weight of the ester oil. 
   
   
       13 . The refrigeration system according to  claim 10 , wherein the expansion mechanism has a capillary tube. 
   
   
       14 . The hermetic compressor according to  claim 2 , wherein the electric element comprises:
 an enameled copper wire; and   an insulating film,   the enameled copper wire has one of an upper-layer polyamide-imide/lower-layer polyester imide copper wire and upper-layer polyamide-imide/lower-layer modified polyester copper wire, and
 the insulating film is made of any one of polyethylene terephthalate, polyethylene naphthalate, polyamide-imide coat polyester, polyphenylene sulfide, and polyether ether ketone. 
   
   
   
       15 . The hermetic compressor according to  claim 2 , wherein the compression element has a suction muffler, and
 the suction muffler is made of any one of low oligomer polyethylene terephthalate, polyethylene terephthalate containing no paraffin, polyethylene naphthalate, polyamide-imide coat polyester, polyphenylene sulfide, and polyether ether ketone.   
   
   
       16 . The hermetic compressor according to  claim 2 , further comprising a rubber part in the hermetic container, and
 the rubber part is made of any of nitrile rubber, hydrogenerated nitrile rubber, and fluororubber.   
   
   
       17 . The hermetic compressor according to  claim 2 , wherein the compression element has a sliding part, and
 the sliding part is made of any one of combination of gray cast irons, combination of the gray cast iron and a spheroidal graphite cast iron, combination of the gray cast iron and a sintered metal, combination of the gray cast iron and a high-silicon aluminum material, combination of the spheroidal graphite cast iron and the high-silicon aluminum, combination of the high-silicon aluminum material and a chrome molybdenum steel material subjected to a carburizing process, and combination of the high-silicon aluminum material and the chrome molybdenum steel material subjected to a nitriding process.   
   
   
       18 . The hermetic compressor according to  claim 2 , wherein the refrigeration oil contains a foaming agent. 
   
   
       19 . The hermetic compressor according to  claim 2 , wherein the refrigeration oil contains an antioxidant agent. 
   
   
       20 . The hermetic compressor according to  claim 2 , wherein the refrigeration oil contains an extreme-pressure additive agent. 
   
   
       21 . A refrigeration system comprising:
 the hermetic compressor according to  claim 2 ;   an evaporator;
 a condenser; and 
   an expansion mechanism.   
   
   
       22 . The refrigeration system according to  claim 21 , wherein the refrigeration oil is mixed with ester oil, and
 the ester oil is obtained by a reaction between an aliphatic alcohol and a fatty acid whose temperature of two-phase separation from a hydrofluorocarbon refrigerant is −35 degrees centigrade or lower at a lower critical temperature and 70 degrees centigrade or higher at an upper critical temperature.   
   
   
       23 . The refrigeration system according to  claim 22 , wherein the refrigeration oil is mixed with 1 to 50% by weight of the ester oil. 
   
   
       24 . The refrigeration system according to  claim 21 , wherein the expansion mechanism has a capillary tube.