Optimizing power usage in a modular outdoor refrigeration system

Abstract

A method for a refrigeration system includes receiving a temperature difference (TD) setpoint indicating a desired temperature difference between outside air and refrigerant and modifying the TD setpoint based on conditions currently being experienced by the refrigeration system. The modified TD setpoint is selected to cause a decrease in total power consumption, wherein the total power consumption comprises power consumed by a compressor to yield a discharge pressure and power consumed by a condenser fan to operate a fan speed.

1 . A refrigeration system comprising:
 a compressor operable to apply compression to refrigerant in order to yield a discharge pressure at which the refrigerant is discharged from the compressor;   a condenser;   a condenser fan having a fan speed configured to control a temperature of the refrigerant based on a temperature difference (TD) setpoint, the TD setpoint indicating a desired temperature difference between outside air and the refrigerant discharged from the condenser; and   a controller operable to modify the TD setpoint based on conditions currently being experienced by the refrigeration system, the modified TD setpoint selected to cause a decrease in total power consumption, wherein the total power consumption comprises power consumed by the compressor to yield the discharge pressure and power consumed by the condenser fan to operate at the fan speed.   
     
     
         2 . The refrigeration system of  claim 1 , wherein the conditions currently being experienced by the refrigeration system comprise an outdoor temperature. 
     
     
         3 . The refrigeration system of  claim 1 , wherein the conditions currently being experienced by the refrigeration system comprise loading conditions of the compressor. 
     
     
         4 . The refrigeration system of  claim 1 , wherein modifying the TD setpoint causes the power consumed by the compressor to decrease more than the power consumed by the condenser fan increases. 
     
     
         5 . The refrigeration system of  claim 1 , wherein modifying the TD setpoint causes the power consumed by the condenser fan to decrease more than the power consumed by the compressor increases. 
     
     
         6 . The refrigeration system of  claim 1 , the controller further operable to save the modified TD setpoint as an optimal TD setpoint for the conditions currently being experienced by the refrigeration system in response to feedback indicating that the modified TD setpoint caused the total power consumption to decrease. 
     
     
         7 . The refrigeration system of  claim 1 , the controller further operable to:
 monitor feedback indicating the total power usage associated with each of a plurality of TD setpoints that have been applied under the conditions currently being experienced by the refrigeration system; and   save the most energy efficient of the plurality of TD setpoints as an optimal TD setpoint for the conditions currently being experienced by the refrigeration system.   
     
     
         8 . A method for a refrigeration system, comprising:
 receiving a temperature difference (TD) setpoint indicating a desired temperature difference between outside air and refrigerant; and   modifying the TD setpoint based on conditions currently being experienced by the refrigeration system, the modified TD setpoint selected to cause a decrease in total power consumption, wherein the total power consumption comprises power consumed by a compressor to yield a discharge pressure and power consumed by a condenser fan to operate a fan speed.   
     
     
         9 . The method of  claim 8 , wherein the conditions being experienced by the refrigeration system comprise an outdoor temperature. 
     
     
         10 . The method of  claim 8 , wherein the conditions currently being experienced by the refrigeration system comprise loading conditions of the compressor. 
     
     
         11 . The method of  claim 8 , wherein modifying the TD setpoint causes the power consumed by the compressor to decrease more than the power consumed by the condenser fan increases. 
     
     
         12 . The method of  claim 8 , wherein modifying the TD setpoint causes the power consumed by the condenser fan to decrease more than the power consumed by the compressor increases. 
     
     
         13 . The method of  claim 8 , further comprising saving the modified TD setpoint as an optimal TD setpoint for the conditions currently being experienced by the refrigeration system in response to feedback indicating that the modified TD setpoint caused the total power consumption to decrease. 
     
     
         14 . A controller for a refrigeration system, the controller comprising one or more processors and logic encoded in non-transitory computer readable memory, the logic, when executed by one or more processors, operable to:
 receive a temperature difference (TD) setpoint indicating a desired temperature difference between outside air and refrigerant;   modify the TD setpoint based on conditions currently being experienced by the refrigeration system, the modified TD setpoint selected to cause a decrease in total power consumption, wherein the total power consumption comprises power consumed by a compressor to yield a discharge pressure and power consumed by a condenser fan to operate a fan speed.   
     
     
         15 . The controller of  claim 14 , wherein the conditions currently being experienced by the refrigeration system comprise an outdoor temperature. 
     
     
         16 . The controller of  claim 14 , wherein the conditions currently being experienced by the refrigeration system comprise loading conditions of the compressor. 
     
     
         17 . The controller of  claim 14 , wherein modifying the TD setpoint causes the power consumed by the compressor to decrease more than the power consumed by the condenser fan increases. 
     
     
         18 . The controller of  claim 14 , wherein modifying the TD setpoint causes the power consumed by the condenser fan to decrease more than the power consumed by the compressor increases. 
     
     
         19 . The controller of  claim 14 , further operable to:
 save the modified TD setpoint as an optimal TD setpoint for the conditions currently being experienced by the refrigeration system in response to feedback indicating that the modified TD setpoint caused the total power consumption to decrease.   
     
     
         20 . The controller of  claim 14 , further operable to:
 monitor feedback indicating the total power usage associated with each of a plurality of TD setpoints that have been applied under the conditions currently being experienced by the refrigeration system; and   save the most energy efficient of the plurality of TD setpoints as an optimal TD setpoint for the conditions currently being experienced by the refrigeration system.