Supercritical refrigeration cycle

Abstract

A supercritical refrigeration cycle comprises a radiator 2 for cooling the refrigerant discharged from a compressor 1 , a cooling fan 2 a for blowing the atmospheric air to the radiator 2 , a decompression unit 4 for decompressing the refrigerant at the outlet of the radiator 2 and having the opening degree thereof controlled to achieve a target high pressure, and an evaporator 5 for evaporating the low-pressure refrigerant decompressed by the decompression unit 4 . The high pressure exceeds the critical pressure of the refrigerant. A value of information representing the difference between the actual radiation state of the refrigerant at the outlet of the radiator 2 and the ideal radiation state determined by the atmospheric temperature is calculated, and based on this value of information, the air capacity of the cooling fan 2 a is controlled to decrease the difference. Thus, the cooling fan of the high-pressure radiator can be properly controlled in the supercritical refrigeration cycle.

1 . A supercritical refrigeration cycle where the high pressure exceeds the critical pressure of the refrigerant, comprising: 
 a compressor for sucking in and compressing a refrigerant;    a radiator for cooling the refrigerant discharged from the compressor by exchanging heat between the refrigerant discharged from the compressor and the atmospheric air;    a cooling fan for blowing the atmospheric air to the radiator;    a decompressor for decompressing the refrigerant at the outlet of the radiator and having the opening degree thereof controlled to achieve a target high pressure; and    an evaporator for evaporating the low-pressure refrigerant decompressed by the decompressor and leading the evaporated gas refrigerant to the inlet of the compressor;    wherein an value of information representing the difference between the actual radiation state of the refrigerant at the outlet of the radiator and the ideal radiation state determined by the atmospheric temperature is calculated, and    wherein the air capacity of the cooling fan is controlled in such a manner as to decrease the difference based on the value of information.    
   
   
       2 . A supercritical refrigeration cycle according to  claim 1 , 
 wherein the value of information is specifically the difference between the refrigerant temperature at the outlet of the radiator and the atmospheric temperature.    
   
   
       3 . A supercritical refrigeration cycle according to  claim 2 , 
 wherein, as long as the temperature difference is not less than a predetermined value, the air capacity of the cooling fan is controlled upward while, in the case where the temperature difference is less than the predetermined value, the air capacity of the cooling fan is controlled downward.    
   
   
       4 . A supercritical refrigeration cycle according to  claim 1 , 
 wherein the value of information is the pressure difference between the actual high pressure and the high-pressure setting determined by the atmospheric temperature.    
   
   
       5 . A supercritical refrigeration cycle according to  claim 4 , 
 wherein in the case where the pressure difference is not less than a predetermined value, the air capacity of the cooling fan is controlled upward, while in the case where the pressure difference is less than the predetermined value, the air capacity of the cooling fan is controlled downward.    
   
   
       6 . A supercritical refrigeration cycle mounted on an automotive vehicle according to  claim 1 , 
 wherein a radiator is arranged at a position exposed to the dynamic pressure of the running vehicle, and the air capacity of the passing atmospheric air is changed with the vehicle speed, and    wherein a cooling fan is electrically driven, and the air capacity of the cooling fan is controlled by the voltage across the drive motor of the cooling fan.    
   
   
       7 . A supercritical refrigeration cycle according to  claim 1  wherein it is determined whether the high pressure is not lower than the critical pressure of the refrigerant or not, 
 wherein in the case where the high pressure is not lower than the critical pressure of the refrigerant, the air capacity of the cooling fan is controlled based on the value of information, and    wherein in the case where the high pressure is lower than the critical pressure of the refrigerant, the air capacity of the cooling fan is controlled directly based on the change in the high pressure.