Fan Speed Control For Air-Cooled Condenser In Precision Cooling

Abstract

An air conditioner system including a condenser fan, an ambient temperature sensor, a refrigerant pressure sensor, and a controller. The ambient temperature sensor is to sense ambient temperature at the system. The refrigerant pressure sensor is to sense pressure of a refrigerant of the system. The target refrigerant pressure module is to identify an optimum pressure of the refrigerant in the system. The controller is to generate an output representing a speed of the condenser fan operable to maintain the pressure of the refrigerant at about the optimum pressure as the ambient temperature of the system changes.

What is claimed is: 
     
         1 . An air conditioner system comprising:
 a condenser fan;   an ambient temperature sensor to sense ambient temperature at the system;   a refrigerant pressure sensor to sense pressure of a refrigerant of the system;   a target refrigerant pressure module to identify an optimum pressure of the refrigerant in the system; and   a controller to generate an output representing a speed of the condenser fan operable to maintain the pressure of the refrigerant at about the optimum pressure as the ambient temperature of the system changes.   
     
     
         2 . The air conditioner system of  claim 1 , wherein the controller includes a function module to generate the output of the controller. 
     
     
         3 . The air conditioner system of  claim 1 , wherein the controller includes a PID module to generate the output of the controller. 
     
     
         4 . The air conditioner system of  claim 1 , wherein the output includes a first output generated by a function module of the controller and a second output generated by a PID module of the controller, the second output is generated subsequent to the first output upon expiration of a predetermined time period. 
     
     
         5 . The air conditioner system of  claim 1 , wherein the controller generates an output stopping the condenser fan when a compressor of the system is not activated. 
     
     
         6 . An air conditioner system comprising:
 a compressor;   a condenser fan;   an ambient temperature sensor to sense ambient temperature at the system;   a refrigerant temperature sensor to sense temperature of a refrigerant of the system;   a target refrigerant temperature module to identify an optimum temperature of the refrigerant in the system; and   a controller to generate an output representing a speed of the condenser fan operable to maintain the temperature of the refrigerant at about the optimum temperature.   
     
     
         7 . The air conditioner system of  claim 6 , wherein the controller generates an output stopping the condenser fan within about 30 seconds upon receipt of an input representing that the compressor is not on. 
     
     
         8 . The air conditioner system of  claim 6 , wherein after the controller receives an input representing that the compressor is on, the controller generates an output stopping the condenser fan if the temperature of the refrigerant is not greater than or equal to 15° C. 
     
     
         9 . The air conditioner system of  claim 6 , wherein after the controller receives an input representing that the compressor is on, the controller generates an output running the condenser fan according to a preset speed based on sensed ambient temperature if the temperature of the refrigerant is greater than or equal to 15° C., but not greater than or equal to 25° C. 
     
     
         10 . The air conditioner system of  claim 6 , wherein after the controller receives an input representing that the compressor is on, the controller generates an output running the condenser fan according to both a preset speed based on sensed ambient temperature and an output of a PID module of the controller if the temperature of the refrigerant is greater than or equal to 25° C., but not greater than or equal to 35° C. 
     
     
         11 . A method for controlling a condensing fan of an air conditioner system with a controller comprising:
 determining whether a compressor of the air conditioner system is on or off;   operating the condenser fan of the air conditioner system at a first speed corresponding to a sensed ambient temperature for a predetermined time period when the compressor is on; and   operating the condenser fan at a second speed after expiration of the predetermined time period, the second speed determined by the controller based on the sensed ambient temperature and an error between a sensed refrigerant pressure and a target refrigerant pressure, the second speed sufficient to move the sensed refrigerant pressure to the target refrigerant pressure.   
     
     
         12 . The method of  claim 11 , further comprising determining the second speed with a PID module of the controller. 
     
     
         13 . The method of  claim 11 , further comprising operating the condenser fan at a third speed determined by the controller based on the sensed ambient temperature and an error between a sensed refrigerant temperature and a target refrigerant temperature, the third speed sufficient to move the sensed refrigerant temperature to the target refrigerant temperature. 
     
     
         14 . The method of  claim 13 , further comprising operating the condenser fan at the third speed only when the sensed refrigerant temperature is greater than or equal to 35° C. 
     
     
         15 . A method for controlling a condensing fan of an air conditioner system with a controller comprising:
 stopping the condensing fan when sensed refrigerant temperature is less than a first predetermined refrigerant temperature;   operating the condensing fan at a first speed predetermined to correspond to sensed ambient temperature when sensed refrigerant temperature is greater than or equal to the first predetermined refrigerant temperature and less than a second predetermined refrigerant temperature;   operating the condensing fan at a second speed predetermined to correspond to sensed ambient temperature and based on error between sensed refrigerant temperature and a target refrigerant temperature when sensed refrigerant temperature is greater than or equal to the second predetermined refrigerant temperature and less than a third predetermined refrigerant temperature, the second speed sufficient to move sensed refrigerant temperature to the target refrigerant temperature; and   operating the condensing fan at a third speed based on error between sensed refrigerant temperature and the target refrigerant temperature when sensed refrigerant temperature is greater than or equal to a third predetermined refrigerant temperature that is greater than the second predetermined refrigerant temperature, the third speed sufficient to move sensed refrigerant temperature to the target refrigerant temperature.   
     
     
         16 . The method of  claim 15 , further comprising setting the first predetermined refrigerant temperature to 15° C.; setting the second predetermined refrigerant temperature to 25° C., and setting the third predetermined refrigerant temperature to 35° C. 
     
     
         17 . The method of  claim 15 , further comprising operating the condensing fan at a fourth speed determined by the controller based on sensed ambient temperature and an error between sensed refrigerant pressure and a target refrigerant pressure, the fourth speed sufficient to move sensed refrigerant pressure to the target refrigerant pressure.