Control device for a refrigeration plant, and control method

Abstract

A method of and apparatus for controlling a refrigeration plant having a cooler for cooling cooling air, the surface temperature of the cooler being measured by a single sensor and the cooling-air temperature being derived from the surface temperature of the cooler via a correction factor, the refrigeration plant then being controlled an the basis of the measured temperature value and the derived temperature value.

1 . Method of controlling a refrigeration plant having a cooler ( 8 ) for cooling cooling air, the surface temperature (t K ) of the cooler ( 8 ) being measured by means of a single sensor ( 2 ) and the cooling-air temperature (t L ) being derived from the surface temperature (t K ) of the cooler via a correction factor, the refrigeration plant then being controlled on the basis of the measured temperature value (t K ) and the derived temperature value (t L ).  
     
     
         2 . Method according to  claim 1 , in which, after a predetermined tire after detection via the temperature sensor ( 2 ), according to which the cooling-air temperature incorporating the correction factor is in the desired range, the refrigeration unit is switched off or remains switched off and a fan ( 3 ) on the cooler ( 8 ) is switched on in order to lead cooling air to the cooler ( 8 ), and the actual temperature (t L ) of the cooling air is checked by the temperature sensor ( 2 ) in this way.  
     
     
         3 . Control device for a refrigeration plant having a cooler ( 8 ) for cooling cooling air, for example in a cold storage room, by means of which device the cooling-air temperature (t L ) is kept at a predefined value, comprising a single sensor ( 2 ) for determining the surface temperature (t K ) on the cooler ( 8 ) and a control unit ( 1 ) which derives the cooling-air temperature (t L ) from the measured surface temperature of the cooler ( 8 ) via a correction factor (K) and controls the refrigeration plant on the basis of the cooling-air temperature (t L ) determined in this way, in conjunction with the measured surface temperature (t K ) of the cooler ( 8 ).  
     
     
         4 . Control device according to  claim 3 , the temperature sensor ( 2 ) being arranged between the cooling fins ( 17 ) of the cooler ( 8 ) in the evaporator ( 9 ) of the refrigeration plant.  
     
     
         5 . Control device according to claims  3  and  4 , the control unit ( 1 ) controlling the compressor ( 4 ), the defrost heater ( 6 ) and the fan ( 3 ) in the evaporator ( 9 ) of a refrigeration plant as a function of the measured temperature value (t K ) on the cooler surface.  
     
     
         6 . Control device according to  claims 3  to  5 , the control unit ( 1 ) displaying the cooling-air temperature (t L ), detected via the correction value, in a display as the room air temperature and, if appropriate, storing and logging the said cooling-air temperature.  
     
     
         7 . A method of controlling a refrigeration plant having a cooler for cooling cooling air comprising: 
 measuring surface temperature (t K ) of the cooler with a single sensor;    determining cooling-air temperature (t L ) from the surface temperature (t K ) of the cooler with a correction factor; and    controlling operation of the cooler on the basis of the measured temperature value (t K ) and the cooling-air temperature value (t L ).    
     
     
         8 . The method according to  claim 7 , wherein after a predetermined time after detection via the temperature sensor, according to which the cooling-air temperature incorporating the correction factor is in a selected range, the refrigeration unit is switched off or remains switched off and a fan associated with the cooler is switched on to lead cooling air to the cooler, and actual temperature (t L ) of the cooling air is checked by the temperature sensor.  
     
     
         9 . A control device for a refrigeration plant having a cooler for cooling cooling air, wherein cooling-air temperature (t L ) is kept at a selected value comprising: 
 a single sensor for determining the surface temperature (t K ) on the cooler; and    a controller which determines the cooling-air temperature (t L ) from measured surface temperature of the cooler with a correction factor (K) and controls the refrigeration plant on the basis of the cooling-air temperature (t L ) in conjunction with the measured surface temperature (t K ) of the cooler.    
     
     
         10 . The control device according to  claim 8 , wherein the sensor is arranged between cooling fins of the cooler in an evaporator connected to the refrigeration plant.  
     
     
         11 . The control device according to  claim 9 , wherein the control unit controls a compressor, a defrost heater and a fan in an evaporator of the refrigeration plant as a function of the measured temperature value (t K ) on a surface of the cooler.  
     
     
         12 . The control device according to  claim 10 , wherein the control unit controls a compressor, a defrost heater and a fan in an evaporator of the refrigeration plant as a function of the measured temperature value (t K ) on a surface of the cooler.  
     
     
         13 . The control device according to  claim 9 , wherein the control device displays the cooling-air temperature (t L ), detected via the correction value, on a display as the room air temperature and, optionally, stores and logs the cooling-air temperature.  
     
     
         14 . The control device according to  claim 10 , wherein the control device displays the cooling-air temperature (t L ), detected via the correction value, on a display as the room air temperature and, optionally, stores and logs the cooling-air temperature.  
     
     
         15 . The control device according to  claim 11 , wherein the control device displays the cooling-air temperature (t L ), detected via the correction value, on a display as the room air temperature and, optionally, stores and logs the cooling-air temperature.  
     
     
         16 . The control device according to  claim 12 , wherein the control device displays the cooling-air temperature (t L ), detected via the correction value, on a display as the room air temperature and, optionally, stores and logs the cooling-air temperature.