Systems and methods for pumped refrigerant economization superheat control

Abstract

A superheat control circuit of a refrigeration system is disclosed. The superheat control circuit comprising: a temperature sensor configured to measure temperature of refrigerant of the refrigeration system and generate temperature data associated with the measured temperature of the refrigerant; a pressure sensor configured to measure pressure of the refrigerant and generate pressure data associated with the measured pressure of the refrigerant; and a controller configured to receive the temperature data and the pressure data, calculate, based on the temperature data and the pressure data, superheat of the refrigerant, and adjust a speed of a fan of a condenser of the refrigeration system based on the calculated superheat of the refrigerant.

What is claimed is: 
     
         1 . A system for superheat control, the system comprising:
 a temperature sensor configured to:
 measure a temperature of a refrigerant of a refrigeration system; and 
 generate temperature data associated with the temperature of the refrigerant; 
   a pressure sensor configured to:
 measure a pressure of the refrigerant; and 
 generate pressure data associated with the pressure of the refrigerant; and 
   a controller configured to:
 receive the temperature data; 
 receive the pressure data; 
 calculate, based on the temperature data and the pressure data, a superheat value of the refrigerant; and 
 adjust a speed of a fan of a condenser of the refrigeration system based on the calculated superheat value of the refrigerant. 
   
     
     
         2 . The system of  claim 1 , wherein the temperature of the refrigerant and the pressure of the refrigerant are measured before the refrigerant enters the condenser. 
     
     
         3 . The system of  claim 1 , wherein the temperature of the refrigerant and the pressure of the refrigerant are measured after the refrigerant exits an evaporator of the refrigeration system and before the refrigerant enters a compressor of the refrigeration system. 
     
     
         4 . The system of  claim 1 , wherein the controller is further configured to adjust the speed of the fan based on the calculated superheat value. 
     
     
         5 . The system of  claim 1 , wherein the controller is further configured to adjust the speed of the fan based on a superheat setpoint. 
     
     
         6 . The system of  claim 5 , wherein the superheat setpoint is adjusted based on at least one of ambient air temperature, return and supply air temperatures, and airflow across an evaporator of the refrigeration system. 
     
     
         7 . The system of  claim 1 , further comprising:
 an electronic expansion valve configured to control flow of the refrigerant entering an evaporator of the refrigeration system, wherein the controller is further configured to adjust a position of the electronic expansion valve based on the calculated superheat value to adjust the flow of the refrigerant.   
     
     
         8 . The system of  claim 1 , wherein the controller is further configured to adjust the speed of the fan based on a mapping function, the mapping function being based on a relationship between the calculated superheat value of the refrigerant and a refrigerant temperature setpoint. 
     
     
         9 . A method for operating a superheat control circuit of a refrigeration system, the method comprising:
 measuring a temperature of a refrigerant of the refrigeration system;   measuring a pressure of the refrigerant;   calculating, based on the measured temperature and the measured pressure, a superheat value of the refrigerant; and   adjusting, based on calculated superheat value, a speed of a fan of a condenser of the refrigeration system.   
     
     
         10 . The method of  claim 9 , wherein the measured temperature of the refrigerant and the measured pressure of the refrigerant are measured before the refrigerant enters the condenser. 
     
     
         11 . The method of  claim 9 , wherein the measured temperature of the refrigerant and the measured pressure of the refrigerant are measured after the refrigerant exits an evaporator of the refrigeration system and before the refrigerant enters a compressor of the refrigeration system. 
     
     
         12 . The method of  claim 9 , further comprising:
 adjusting the speed of the fan in a stepped response based on the calculated superheat value.   
     
     
         13 . The method of  claim 9 , further comprising:
 adjusting the speed of the fan based on a superheat setpoint.   
     
     
         14 . The method of  claim 13 , further comprising:
 adjusting the superheat setpoint based on at least one of ambient air temperature, return and supply air temperatures, and airflow across an evaporator of the refrigeration system.   
     
     
         15 . The method of  claim 9 , further comprising:
 controlling, through an electronic expansion valve, flow of the refrigerant entering an evaporator of the refrigeration system; and   adjusting a position of the electronic expansion valve based on the calculated superheat value to adjust the flow of the refrigerant.   
     
     
         16 . The method of  claim 9 , further comprising:
 adjusting the speed of the fan based on a mapping function, the mapping function being based on a relationship between the calculated superheat value of the refrigerant and a refrigerant temperature setpoint.   
     
     
         17 . A superheat control circuit of a refrigeration system, the superheat control circuit comprising:
 a temperature sensor configured to measure temperature of refrigerant of the refrigeration system and generate temperature data associated with the measured temperature of the refrigerant; and   a pressure sensor configured to measure pressure of the refrigerant and generate pressure data associated with the measured pressure of the refrigerant, wherein a controller: calculates, based on the temperature data and the pressure data, a superheat value of the refrigerant; and adjust a speed of a fan of a condenser of the refrigeration system based a comparison of the superheat value of the refrigerant and a superheat setpoint.   
     
     
         18 . The superheat control circuit of  claim 17 , wherein the measured temperature of the refrigerant and the measured pressure of the refrigerant are measured prior to the refrigerant entering the condenser. 
     
     
         19 . The superheat control circuit of  claim 17 , wherein the measured temperature of the refrigerant and the measured pressure of the refrigerant are measured after the refrigerant exits an evaporator of the refrigeration system. 
     
     
         20 . The superheat control circuit of  claim 17 , wherein the controller is configured to adjust the speed of the fan in a stepped response based on the superheat value.