Cooling system

Abstract

An apparatus includes an expansion valve, a load, a sensor, an exhaust system, and a controller. The expansion valve cools a refrigerant. The load uses the refrigerant to cool a space. The sensor detects a concentration of the refrigerant in the space. The exhaust system evacuates the refrigerant from the space. The controller determines whether the detected concentration of the refrigerant in the space exceeds a first threshold and in response to a determination that the detected concentration of the refrigerant exceeds the first threshold, closes the expansion valve. The controller also determines whether the detected concentration of the refrigerant in the space exceeds a second threshold and in response to a determination that the detected concentration of the refrigerant exceeds the second threshold, activates the exhaust system.

What is claimed is: 
     
         1 . An apparatus comprising:
 an expansion valve configured to cool a refrigerant;   a load configured to use the refrigerant to cool a space;   a sensor configured to detect a concentration of the refrigerant in the space;   an exhaust system configured to evacuate the refrigerant from the space; and   a controller configured to:
 determine whether the detected concentration of the refrigerant in the space exceeds a first threshold; 
 in response to a determination that the detected concentration of the refrigerant exceeds the first threshold, close the expansion valve; 
 determine whether the detected concentration of the refrigerant in the space exceeds a second threshold; and 
 in response to a determination that the detected concentration of the refrigerant exceeds the second threshold, activate the exhaust system. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the controller is further configured to activate an alarm in response to the determination that the detected concentration of the refrigerant exceeds the second threshold. 
     
     
         3 . The apparatus of  claim 1 , further comprising a check valve coupled to a discharge of the load and configured to prevent the refrigerant from backflowing into the load. 
     
     
         4 . The apparatus of  claim 1 , further comprising a full-port solenoid valve coupled to a discharge of the load and configured to prevent the refrigerant from backflowing into the load. 
     
     
         5 . The apparatus of  claim 1 , wherein the first threshold is 1000 parts per million and the second threshold is 5000 parts per million. 
     
     
         6 . The apparatus of  claim 1 , further comprising a pressure transducer configured to convert a pressure of the refrigerant at the load to an electric signal, the controller further configured to determine that a refrigerant leak is occurring in the load based on the electric signal. 
     
     
         7 . The apparatus of  claim 6 , wherein the electric signal indicates that the pressure of the refrigerant that the load is decreasing. 
     
     
         8 . A method comprising:
 cooling a refrigerant using an expansion valve;   using the refrigerant to cool a space proximate a load;   detecting a concentration of the refrigerant in the space using a sensor;   determining whether the detected concentration of the refrigerant in the space exceeds a first threshold;   in response to a determination that the detected concentration of the refrigerant exceeds the first threshold, closing the expansion valve;   determining whether the detected concentration of the refrigerant in the space exceeds a second threshold; and   in response to a determination that the detected concentration of the refrigerant exceeds the second threshold, activating an exhaust system to evacuate the refrigerant from the space.   
     
     
         9 . The method of  claim 8 , further comprising activating an alarm in response to the determination that the detected concentration of the refrigerant exceeds the second threshold. 
     
     
         10 . The method of  claim 8 , further comprising preventing the refrigerant from backflowing into the load using a check valve coupled to a discharge of the load. 
     
     
         11 . The method of  claim 8 , further comprising preventing the refrigerant from backflowing into the load using a full-port solenoid valve coupled to a discharge of the load. 
     
     
         12 . The method of  claim 8 , wherein the first threshold is 1000 parts per million and the second threshold is 5000 parts per million. 
     
     
         13 . The method of  claim 8 , further comprising:
 converting, by a pressure transducer, a pressure of the refrigerant at the load to an electric signal; and   determining that a refrigerant leak is occurring in the load based on the electric signal.   
     
     
         14 . The method of  claim 13 , wherein the electric signal indicates that the pressure of the refrigerant that the load is decreasing. 
     
     
         15 . A system comprising:
 a high side heat exchanger configured to remove heat from a refrigerant;   an expansion valve configured to cool the refrigerant from the high side heat exchanger;   a load configured to use the refrigerant to cool a space;   a sensor configured to detect a concentration of the refrigerant in the space;   an exhaust system configured to evacuate the refrigerant from the space; and   a controller configured to:
 determine whether the detected concentration of the refrigerant in the space exceeds a first threshold; 
 in response to a determination that the detected concentration of the refrigerant exceeds the first threshold, close the expansion valve; 
 determine whether the detected concentration of the refrigerant in the space exceeds a second threshold; and 
 in response to a determination that the detected concentration of the refrigerant exceeds the second threshold, activate the exhaust system. 
   
     
     
         16 . The system of  claim 15 , wherein the controller is further configured to activate an alarm in response to the determination that the detected concentration of the refrigerant exceeds the second threshold. 
     
     
         17 . The system of  claim 15 , further comprising a check valve coupled to a discharge of the load and configured to prevent the refrigerant from backflowing into the load. 
     
     
         18 . The system of  claim 15 , further comprising a full-port solenoid valve coupled to a discharge of the load and configured to prevent the refrigerant from backflowing into the load. 
     
     
         19 . The system of  claim 15 , wherein the first threshold is 1000 parts per million and the second threshold is 5000 parts per million. 
     
     
         20 . The system of  claim 15 , further comprising a pressure transducer configured to convert a pressure of the refrigerant at the load to an electric signal, the controller further configured to determine that a refrigerant leak is occurring in the load based on the electric signal. 
     
     
         21 . The system of  claim 20 , wherein the electric signal indicates that the pressure of the refrigerant that the load is decreasing.