Refrigeration system

Abstract

When a guard timer of a compressor ( 141 ) expires, an R 2 signal from a control section ( 140 ) of an outdoor unit is turned on (Action I). If a control section ( 120 ) of a freezer unit recognizes from an inside temperature detected by a temperature sensor ( 124 ) that the R 2 signal is turned on and a request for a shift to a freezer thermo-on state is raised (Action II), a freezer electromagnetic valve ( 121 ) is opened (Action III). In general, when the electromagnetic valve ( 121 ) is opened, it is supposed that an increase in refrigerant suction pressure is detected by a pressure sensor ( 146 ) and then the compressor ( 141 ) is actuated. However, if an outside air temperature is low, the refrigerant suction pressure remains lower than a predetermined value. Therefore, the control section ( 120 ) actuates a booster compressor ( 131 ) (Action IV) to raise the refrigerant suction pressure of the compressor ( 141 ).

1 . A refrigeration system ( 1 ) for vapor compression refrigeration cycle including a heat source circuit provided with a high temperature compressor ( 141 ) and a utilization circuit connected to the heat source circuit and provided with an evaporator ( 123 ) and a low temperature compressor ( 131 ), the refrigeration system ( 1 ) comprising: 
 an operation control means for switching the high temperature compressor ( 141 ) between actuated state and suspended state based on a refrigerant suction pressure; and    an actuation control means for actuating the low temperature compressor ( 131 ) to increase the refrigerant suction pressure of the high temperature compressor ( 141 ) when the high temperature compressor ( 141 ) is suspended and given conditions including a condition concerning a request for cooling in the evaporator ( 123 ) are met.    
   
   
       2 . A refrigeration system ( 2 ) for vapor compression refrigeration cycle comprising: 
 an operation control means for switching a compressor ( 241 ) between actuated state and suspended state based on a refrigerant suction pressure; and    a reference value changing means for reducing a reference value of the refrigerant suction pressure for judging whether to actuate the compressor ( 241 ) or not when the compressor ( 241 ) is suspended and an outside air temperature is reduced from a predetermined temperature.    
   
   
       3 . The refrigeration system ( 2 ) of  claim 2 , wherein 
 the reference value changing means is adapted to reduce the reference value in stages based on the amount of reduction in outside air temperature from the predetermined temperature.    
   
   
       4 . A refrigeration system ( 3 ) for vapor compression refrigeration cycle comprising: 
 an operation control means for switching a compressor ( 341 ) between actuated state and suspended state based on a refrigerant suction pressure; and    a power supply control means for supplying open phase current to a motor of the compressor ( 341 ) to increase the refrigerant suction pressure increases when the compressor ( 341 ) is suspended, an outside air temperature is reduced from a predetermined temperature and a condition concerning a request for cooling in an evaporator ( 313 ) is met.