Methods of servicing mobile air conditioning systems

Abstract

The present invention relates to methods and systems for introducing one or more hydrohalocarbon refrigerants into a heat transfer system from a vessel by recovering the one or more hydrohalocarbon refrigerants from the heat transfer system; monitoring the vapor pressure in the vessel and if the vapor pressure in the vessel becomes greater than 3 psi over the expected saturation pressure for the one or more hydrohalocarbon refrigerants then releasing vapor from the vessel; and returning said one or more hydrohalocarbon refrigerants to the heat transfer system by drawing liquid refrigerant from the vessel.

1 . A method for introducing one or more hydrohalocarbon refrigerants into a heat transfer system comprising:
 recovering from a heat transfer system one or more hydrohalocarbon refrigerants and providing the one or more hydrohalocarbon refrigerants to a vessel;   monitoring the vapor pressure in the vessel and if the vapor pressure in the vessel becomes greater than 3 psi over the expected saturation pressure for the one or more hydrohalocarbon refrigerants then releasing vapor from the vessel; and   returning the one or more hydrohalocarbon refrigerants to the heat transfer system by drawing liquid refrigerant from the vessel.   
     
     
         2 . The method of  claim 1  wherein the one or more hydrohalocarbon refrigerants are selected from the group consisting of HFC-134a, HFO-1234yf, and combinations thereof. 
     
     
         3 . The method of  claim 1  wherein the vapor pressure is released from the vessel when it becomes at least 5 psi greater than the expected saturation pressure for the one or more hydrohalocarbon refrigerants. 
     
     
         4 . The method of  claim 1  wherein the vapor pressure is released from the vessel when it becomes at least 6 psi greater than the expected saturation pressure for the one or more hydrohalocarbon refrigerants. 
     
     
         5 . The method of  claim 1  wherein the vapor pressure is released from the vessel when it becomes between 7 psi and 8 psi greater than the expected saturation pressure for the one or more hydrohalocarbon refrigerants. 
     
     
         6 . The method of  claim 1  wherein the one or more hydrohalocarbon refrigerants are stored in the vessel as both a liquid phase and a vapor phase. 
     
     
         7 . The method of  claim 6  wherein the vapor phase further comprises one or more non-condensable gases. 
     
     
         8 . The method of  claim 7  wherein the non-condensable gas comprises CO 2 . 
     
     
         9 . A method for introducing one or more hydrohalocarbon refrigerants selected from the group consisting of HFC-134a, HFO-1234yf, and combinations thereof, to a heat transfer system from a vessel comprising:
 releasing vapor pressure from within the vessel when the vapor pressure becomes greater than 3 psi over the expected saturation pressure for the one or more hydrohalocarbon refrigerants; and   providing the one or more hydrohalocarbon refrigerants to the heat transfer system by drawing liquid refrigerant from the vessel.   
     
     
         10 . The method of  claim 9  wherein the one or more hydrohalocarbon refrigerants comprise a combination of HFC-134a and HFO-1234yf. 
     
     
         11 . The method of  claim 9  wherein the vapor pressure is released from the vessel when the vapor pressure becomes at least 5 psi greater than the expected saturation pressure for the one or more hydrohalocarbon refrigerants. 
     
     
         12 . The method of  claim 9  wherein the vapor pressure is released from the vessel when the vapor pressure becomes at least 6 psi greater than the expected saturation pressure for the one or more hydrohalocarbon refrigerants. 
     
     
         13 . The method of  claim 9  wherein the vapor pressure is released from the vessel when the vapor pressure becomes between 7 psi and 8 psi greater than the expected saturation pressure for the one or more hydrohalocarbon refrigerants. 
     
     
         14 . The method of  claim 9  wherein the one or more hydrohalocarbon refrigerants are stored in the vessel in both a liquid phase and a vapor phase. 
     
     
         15 . The method of  claim 14  wherein the vapor phase further comprises one or more non-condensable gases. 
     
     
         16 . The method of  claim 15  wherein the non-condensable gas comprises CO 2 . 
     
     
         17 . A system for introducing one or more hydrohalocarbon refrigerants into a heat transfer system comprising:
 a vessel for storing one or more hydrohalocarbon refrigerants;   an automatic purge valve assembly set to release vapor pressure in the vessel when it becomes greater than 3 psi over the expected saturation pressure for the one or more hydrohalocarbon refrigerants;   an input line for providing the one or more hydrohalocarbon refrigerants from the heat transfer system to the vessel; and   an output line for returning liquid refrigerant from the vessel to the heat transfer system.   
     
     
         18 . The system of  claim 17  wherein the one or more hydrohalocarbon refrigerants are selected from the group consisting of HFC-134a, HFO-1234yf, and combinations thereof. 
     
     
         19 . The system of  claim 17  wherein the automatic purge value assembly comprises a purge line, a purge valve, and a control system. 
     
     
         20 . The system of  claim 19  wherein the automatic purge value assembly further comprises a pressure transducer and, optionally, a temperature transducer.