Vapor compression refrigeration circuit and automotive air-conditioning system using same

Abstract

A vapor compression refrigeration circuit comprises a compressor, a heat radiator, a high-temperature section of an internal heat exchanger, a pressure reducer, an evaporator, an accumulator and a low-temperature section of the internal heat exchanger disposed in this order in a circulation passage through which a refrigerant circulates, when viewed along a direction of flow of the refrigerant. The pressure reducer, the accumulator and the internal heat exchanger are integrally formed.

1 . A vapor compression refrigeration circuit, comprising:
 a compressor, a heat radiator, a high-temperature section of an internal heat exchanger, a pressure reducer, an evaporator, an accumulator and a low-temperature section of the internal heat exchanger disposed in this order in a circulation passage through which a refrigerant circulates, when viewed along a direction of flow of the refrigerant, wherein   the pressure reducer, the accumulator and the internal heat exchanger are integrally formed.   
   
   
       2 . The vapor compression refrigeration circuit according to  claim 1 , wherein
 the pressure reducer is adjacent to the accumulator.   
   
   
       3 . The vapor compression refrigeration circuit according to  claim 2 , further comprising
 a superheat reduction device for heat exchange between a liquid-phase component of the refrigerant accumulated in the accumulator and a vapor-phase component of the refrigerant exiting the low-temperature section of the internal heat exchanger.   
   
   
       4 . The vapor compression refrigeration circuit according to  claim 3 , wherein
 the superheat reduction device includes a pipe disposed in a part of the circulation passage between the low-temperature section of the internal heat exchanger and the compressor, the pipe passing across a bottom side part of the accumulator.   
   
   
       5 . The vapor compression refrigeration circuit according to  claim 4 , wherein
 the superheat reduction device further includes surface irregularities formed on at least one of inner and outer peripheral surfaces of the pipe.   
   
   
       6 . The vapor compression refrigeration circuit according to  claim 5 , wherein
 the pipe has an oil return hole for drawing in a lubricating oil accumulated in the accumulator.   
   
   
       7 . The vapor compression refrigeration circuit according to  claim 6 , wherein
 the pipe has an inlet end and an outlet end each connected to an inner wall surface of the accumulator, where the outlet end is at a higher position than the inlet end and a surface of the liquid-phase component of the refrigerant accumulated in the accumulator.   
   
   
       8 . The vapor compression refrigeration circuit according to  claim 7 , wherein
 the refrigerant is CO 2 .   
   
   
       9 . An automotive air-conditioning system, comprising:
 a vapor compression refrigeration circuit provided in a vehicle, the vapor compression refrigeration circuit comprising a compressor, a heat radiator, a high-temperature section of an internal heat exchanger, a pressure reducer, an evaporator, an accumulator and a low-temperature section of the internal heat exchanger disposed in this order in a circulation passage through which a refrigerant circulates, when viewed along a direction of flow of the refrigerant, wherein   the pressure reducer, the accumulator and the internal heat exchanger are integrally formed.   
   
   
       10 . The automotive air-conditioning system according to  claim 9 , wherein
 the pressure reducer is adjacent to the accumulator.   
   
   
       11 . The automotive air-conditioning system according to  claim 10 , further comprising
 a superheat reduction device for heat exchange between a liquid-phase component of the refrigerant accumulated in the accumulator and a vapor-phase component of the refrigerant exiting the low-temperature section of the internal heat exchanger.   
   
   
       12 . The automotive air-conditioning system according to  claim 11 , wherein
 the superheat reduction device includes a pipe disposed in a part of the circulation passage between the low-temperature section of the internal heat exchanger and the compressor, the pipe passing across a bottom side part of the accumulator.   
   
   
       13 . The automotive air-conditioning system according to  claim 12 , wherein
 the superheat reduction device further includes surface irregularities formed on at least one of inner and outer peripheral surfaces of the pipe.   
   
   
       14 . The automotive air-conditioning system according to  claim 13 , wherein
 the pipe has an oil return hole for drawing in a lubricating oil accumulated in the accumulator.   
   
   
       15 . The automotive air-conditioning system according to  claim 14 , wherein
 the pipe has an inlet end and an outlet end each connected to an inner wall surface of the accumulator, where the outlet end is at a higher position than the inlet end and a surface of the liquid-phase component of the refrigerant accumulated in the accumulator.   
   
   
       16 . The automotive air-conditioning system according to  claim 15 , wherein
 the refrigerant is CO 2 .