Refrigeration apparatus

Abstract

A refrigeration apparatus has a compressor, a radiator, and an evaporator connected in order to form a refrigerant circuit. The refrigeration apparatus includes an expansion mechanism disposed at an inflow side of the evaporator, a detector that detects a supercooled state of the refrigerant at the inflow side of the evaporator, and a control part. The expansion mechanism controls expansion of refrigerant based on at least one of a high-pressure target value of the refrigerant circuit, a low-pressure target value of the refrigerant circuit, and a superheat target value at an outflow side of the evaporator. The control part causes at least one of a settings change to raise the high-pressure target value, to lower the low-pressure target value and to raise the superheat target value upon determining based on detection results from the detector that refrigerant at the evaporator inflow side is in a supercooled state.

1 . A refrigeration apparatus in which a compressor, a radiator, and an evaporator are connected in order to form a refrigerant circuit through which a refrigerant circulates, the refrigeration apparatus comprising:
 an expansion mechanism disposed at an inflow side of the evaporator, the expansion mechanism being arranged and configured to control expansion of refrigerant flowing into the evaporator based on at least one of
 a high-pressure target value of the refrigerant circuit, 
 a low-pressure target value of the refrigerant circuit, and 
 a superheat target value at an outflow side of the evaporator; 
   a detector arranged and configured to detect supercooled state of the refrigerant at the inflow side of the evaporator; and   a control part configured and arranged to cause at least one of
 a settings change to raise the high-pressure target value, 
 a settings change to lower the low-pressure target value and 
 a settings change to raise the superheat target value 
   
       upon determining based on detection results from the detector that the refrigerant at the inflow side of the evaporator is in a supercooled state. 
     
     
         2 . The refrigeration apparatus according to  claim 1 , wherein
 the control part is further configured to return the at least one settings change to an original settings when a supercooled state no longer exists after the at least one settings change has been made.   
     
     
         3 . The refrigeration apparatus according to  claim 2 , wherein
 the control part is further configured to furnish a margin to preventing hunting between
 a value when determining that a supercooled state exists in a case where the at least one settings change is to be effected, and 
 a value when determining that a departure has been made from a supercooled state in a case where the at least one settings change is restored to the original settings. 
   
     
     
         4 . The refrigeration apparatus according to  claim 1 , wherein
 the evaporator is a usage-side heat exchanger; and   the control part is configured and arranged to cause at least one of
 a settings change to lower the low-pressure target value and 
 a settings change to raise the superheat target value 
   
       upon determining based on detection results from the detector that the refrigerant at an inflow side of the usage-side heat exchanger is in a supercooled state. 
     
     
         5 . The refrigeration apparatus according to  claim 4 , wherein
 the detector includes
 a first detector arranged and configured to detect pressure saturation temperature at the inflow side of the usage-side heat exchanger, and 
 one of
 a second detector arranged and configured to detect temperature of the refrigerant at the inflow side of the usage-side heat exchanger, and 
 a third detector arranged and configured to detect temperature of the refrigerant at an inflow side of the expansion mechanism; and 
 
   the control part is further configured and arranged to determine whether the refrigerant at the inflow side of the usage-side heat exchanger is in a supercooled state based on
 a comparison of detection results from the first detector and the second detector, or 
 a comparison of detection results from the first detector and the third detector. 
   
     
     
         6 . The refrigeration apparatus according to  claim 5 , wherein
 the third detector is a liquid line temperature sensor disposed at an outflow side of the radiator; and   the control part is further configured to determine whether the refrigerant at the inflow side of the usage-side heat exchanger is in a supercooled state using an obtained temperature as the temperature of the refrigerant at the inflow side of the expansion mechanism, the obtained temperature being obtained by subtracting a correction value from the detected temperature of the liquid line temperature sensor, and the correction value being equivalent to a thermal loss experienced from the liquid line temperature sensor installation location to the expansion mechanism.   
     
     
         7 . The refrigeration apparatus according to  claim 5 , wherein
 the first detector is an intake pressure sensor arranged and configured to detect pressure at an intake side of the compressor; and   the control part is further configured to calculate the pressure saturation temperature from the pressure detected by the intake pressure sensor.   
     
     
         8 . The refrigeration apparatus according to  claim 6 , wherein
 the first detector is an intake pressure sensor arranged and configured to detect pressure at an intake side of the compressor; and   the control part is further configured to calculate the pressure saturation temperature from the pressure detected by the intake pressure sensor.   
     
     
         9 . The refrigeration apparatus according to  claim 2 , wherein
 the evaporator is a usage-side heat exchanger; and   the control part is configured and arranged to cause at least one of
 a settings change to lower the low-pressure target value and 
 a settings change to raise the superheat target value 
   
       upon determining based on detection results from the detector that the refrigerant at an inflow side of the usage-side heat exchanger is in a supercooled state. 
     
     
         10 . The refrigeration apparatus according to  claim 9 , wherein the detector includes
 a first detector arranged and configured to detect pressure saturation temperature at the inflow side of the usage-side heat exchanger, and   one of
 a second detector arranged and configured to detect temperature of the refrigerant at the inflow side of the usage-side heat exchanger, and 
 a third detector arranged and configured to detect temperature of the refrigerant at an inflow side of the expansion mechanism; and 
   the control part is further configured and arranged to determine whether the refrigerant at the inflow side of the usage-side heat exchanger is in a supercooled stake based on
 a comparison of detection results from the first detector and the second detector, or 
 a comparison of detection results from the first detector and the third detector. 
   
     
     
         11 . The refrigeration apparatus according to  claim 10 , wherein
 the third detector is a liquid line temperature sensor disposed at an outflow side of the radiator; and   the control part is further configured to determine whether the refrigerant at the inflow side of the usage-side heat exchanger is in a supercooled state using an obtained temperature as the temperature of the refrigerant at the inflow side of the expansion mechanism, the obtained temperature being obtained by subtracting a correction value from the detected temperature of the liquid line temperature sensor, and the correction value being equivalent to a thermal loss experienced from the liquid line temperature sensor installation location to the expansion mechanism.   
     
     
         12 . The refrigeration apparatus according to  claim 10 , wherein
 the first detector is an intake pressure sensor arranged and configured to detect pressure at an intake side of the compressor; and   the control part is further configured to calculate the pressure saturation temperature from the pressure detected by the intake pressure sensor.   
     
     
         13 . The refrigeration apparatus according to  claim 3 , wherein
 the evaporator is a usage-side heat exchanger; and   the control part is configured and arranged to cause at least one of
 a settings change to lower the low-pressure target value and 
 a settings change to raise the superheat target value 
   
       upon determining based on detection results from the detector that the refrigerant at an inflow side of the usage-side heat exchanger is in a supercooled state. 
     
     
         14 . The refrigeration apparatus according to  claim 13 , wherein the detector includes
 a first detector arranged and configured to detect pressure saturation temperature at the inflow side of the usage-side heat exchanger, and   one of
 a second detector arranged and configured to detect temperature of the refrigerant at the inflow side of the usage-side heat exchanger, and 
 a third detector arranged and configured to detect temperature of the refrigerant at an inflow side of the expansion mechanism; and 
   the control part is further configured and arranged to determine whether the refrigerant at the inflow side of the usage-side heat exchanger is in a supercooled state based on
 a comparison of detection results from the first detector and the second detector, or 
 a comparison of detection results from the first detector and the third detector. 
   
     
     
         15 . The refrigeration apparatus according to  claim 14 , wherein
 the third detector is a liquid line temperature sensor disposed at an outflow side of the radiator; and   the control part is further configured to determine whether the refrigerant at the inflow side of the usage-side heat exchanger is in a supercooled state using an obtained temperature as the temperature of the refrigerant at the inflow side of the expansion mechanism, the obtained temperature being obtained by subtracting a correction value from the detected temperature of the liquid line temperature sensor, and the correction value being equivalent to a thermal loss experienced from the liquid line temperature sensor installation location to the expansion mechanism.   
     
     
         16 . The refrigeration apparatus according to  claim 14 , wherein
 the first detector is an intake pressure sensor arranged and configured to detect pressure at an intake side of the compressor; and   the control part is further configured to calculate the pressure saturation temperature from the pressure detected by the intake pressure sensor.