Refrigeration plant and methods of control therefor

Abstract

A refrigeration plant has a refrigerator circuit comprising a compressor, a condensing coil, an expansion valve and an evaporator. Heat is absorbed in the evaporator and exhausted at the condenser. Pressure is measured at the compressor inlet and a blower arrangement for blowing cool air over a heat transfer surface of the condenser is controlled in dependence upon the pressure measurement.

1 . A refrigeration plant comprising a compressor coupled to receive low pressure refrigerant from a low pressure circuit at a compressor inlet, to compress it to provide high pressure refrigerant, a condenser coupled to receive the high pressure refrigerant and having at least one heat transfer surface to discharge heat from the condenser to provide cooled high pressure refrigerant to an expansion valve and a blower arrangement for blowing cooling air over said at least one heat transfer surface characterised by a blower controller arranged to control the blower in dependence on the pressure in the low pressure circuit. 
     
     
         2 . A refrigeration plant according to  claim 1  wherein the blower controller is coupled to a sensor arranged to provide a variable output indicative of pressure in the low pressure circuit. 
     
     
         3 . A refrigeration plant according to  claim 2  wherein the blower controller comprises a processor arranged to control the fan in dependence on an algorithm taking the pressure as an input. 
     
     
         4 . A refrigeration plant according to  claim 3  in which the controller is operable to determine a discharge pressure in dependence upon the fluid pressure at the compressor inlet and to control the blower based on the determined discharge pressure. 
     
     
         5 . A refrigeration plant according to  claim 4  wherein the blower controller is operable to control the blower based on a difference between the determined discharge pressure and the measured discharge pressure. 
     
     
         6 . A refrigeration plant according to  claim 1 , wherein the blower controller is operable to control the blower in dependence upon a measured ambient temperature. 
     
     
         7 . A refrigeration plant according to  claim 1 , the plant having a cooling capacity of between 1 kw and 20 kw. 
     
     
         8 . A refrigeration plant according to  claim 1 , having a single compressor. 
     
     
         9 . A refrigeration plant according to  claim 1 , having a fixed speed compressor. 
     
     
         10 . A method of controlling a refrigeration plant comprising a compressor, and a blower for cooling a condenser, the method comprising measuring a pressure at a compressor inlet and controlling the blower in dependence upon the measured pressure. 
     
     
         11 . A method according to  claim 10  further comprising controlling the fan in dependence on an algorithm which takes the compressor inlet pressure as an input. 
     
     
         12 . A method according to  claim 11  further comprising determining a discharge pressure in dependence upon the fluid pressure at the compressor inlet and controlling the blower based on the determined discharge pressure. 
     
     
         13 . A method according to  claim 10  comprising receiving a measurement of the discharge pressure at the compressor outlet and controlling the blower based on a difference between the determined discharge pressure and the measurement of the discharge pressure. 
     
     
         14 . A method according to  claim 10 , comprising receiving a measurement of ambient temperature and controlling the blower in dependence upon the measurement of ambient temperature. 
     
     
         15 . A non-transistory computer program product comprising instructions operable to program a processor to measure a pressure at a compressor inlet and control the blower in dependence upon the measured pressure. 
     
     
         16 . A refrigerator comprising the refrigeration plant of  claim 1 .