Heat pump charge compensation for heating mode operation

Abstract

An HVAC system includes a first heat exchange coil with a plurality of coil circuits. For each coil circuit of the plurality of circuits, there is a manifold line fluidly coupling the coil circuit to a compressor of the HVAC system. A check valve is positioned in a first manifold line coupling a first coil circuit of the plurality of coil circuits to the compressor. The check valve is configured to allow flow of refrigerant from the compressor to the first coil circuit when the HVAC system is operating in a cooling mode and prevent flow of refrigerant from the first coil circuit to the compressor when the HVAC system is operating in a heating mode.

What is claimed is: 
     
         1 . A heating, ventilation, and air conditioning (HVAC) system configured to regulate a temperature of a space, the HVAC system comprising:
 a first heat exchange coil comprising a plurality of coil circuits;   for each coil circuit of the plurality of circuits, a manifold line fluidly coupling the coil circuit to a compressor of the HVAC system;   a check valve positioned in a first manifold line coupling a first coil circuit of the plurality of coil circuits to the compressor, wherein the check valve is configured to:
 allow flow of refrigerant from the compressor to the first coil circuit when the HVAC system is operating in a cooling mode; and 
 prevent flow of refrigerant from the first coil circuit to the compressor when the HVAC system is operating in a heating mode. 
   
     
     
         2 . The HVAC system of  claim 1 , further comprising:
 a second heat exchange coil;   an expansion valve positioned between the first heat exchange coil and the second heat exchange coil; and   an expansion valve bypass line fluidly coupling the first coil circuit to the second heat exchange coil and bypassing the expansion valve.   
     
     
         3 . The HVAC system of  claim 2 , wherein the first heat exchange coil is an outdoor coil, and second heat exchange coil is an indoor coil. 
     
     
         4 . The HVAC system of  claim 2 , further comprising, for each coil circuit of the plurality of coil circuits other than the first coil circuit, a conduit coupling the coil circuit to the expansion valve. 
     
     
         5 . The HVAC system of  claim 2 , further comprising a liquid line fluidly coupling the expansion valve and the expansion valve bypass line to the second heat exchange coil. 
     
     
         6 . The system of  claim 1 , wherein the first coil circuit is configured to store refrigerant when the HVAC system is operating in the heating mode. 
     
     
         7 . A heating, ventilation, and air conditioning (HVAC) system configured to regulate a temperature of a space, the HVAC system comprising:
 a first heat exchange coil comprising a plurality of coil circuits;   for each coil circuit of the plurality of circuits, a manifold line fluidly coupling the coil circuit to a compressor of the HVAC system;   a check valve positioned in a first manifold line coupling a first coil circuit of the plurality of coil circuits to the compressor, wherein the check valve is configured to prevent flow of refrigerant from the first coil circuit to the compressor when the HVAC system is operating in a heating mode; and   a controllable valve located in a conduit fluidly coupling the first coil circuit to a second heat exchange coil and configured to be open for at least a period of time when the HVAC system is operating in the heating mode, such that refrigerant is stored in the first coil circuit.   
     
     
         8 . The HVAC system of  claim 7 , wherein the controllable valve is further configured to close after a predetermined period of time of operating the HVAC system in the heating mode. 
     
     
         9 . The HVAC system of  claim 7 , wherein the controllable valve is further configured to close after a predetermined volume of refrigerant is stored in the first coil circuit. 
     
     
         10 . The HVAC system of  claim 7 , further comprising:
 an expansion valve positioned between the first heat exchange coil and the second heat exchange coil; and   an expansion valve bypass line fluidly coupling the first coil circuit to the second heat exchange coil and bypassing the expansion valve, wherein the controllable valve is located in the expansion valve bypass line.   
     
     
         11 . The HVAC system of  claim 7 , wherein the first heat exchange coil is an outdoor coil, and second heat exchange coil is an indoor coil. 
     
     
         12 . The HVAC system of  claim 10 , further comprising, for each coil circuit of the plurality of coil circuits other than the first coil circuit, a conduit coupling the coil circuit to the expansion valve. 
     
     
         13 . The HVAC system of  claim 10 , further comprising a liquid line fluidly coupling the expansion valve and the expansion valve bypass line to the second heat exchange coil. 
     
     
         14 . The HVAC system of  claim 7 , wherein the check valve is further configured to allow flow of refrigerant from the compressor to the first coil circuit when the HVAC system is operating in a cooling mode. 
     
     
         15 . The HVAC system of  claim 7 , wherein the controllable valve is configured to be open when the HVAC system is operating in a cooling mode. 
     
     
         16 . A heating, ventilation, and air conditioning (HVAC) system configured to regulate a temperature of a space, the HVAC system comprising:
 a first heat exchange coil comprising a plurality of coil circuits;   a second heat exchange coil;   an expansion valve positioned between the first heat exchange coil and the second heat exchange coil;   an expansion valve bypass line fluidly coupling a first coil circuit of the plurality of coil circuits to the second heat exchange coil and bypassing the expansion valve; and   a check valve positioned in the expansion valve bypass line coupling the first coil circuit to the second heat exchange coil, wherein the check valve is configured to:
 allow flow of refrigerant from the first coil circuit to the second heat exchange coil when the HVAC system is operating in a cooling mode; and 
 prevent flow of refrigerant from the second heat exchange coil to the first coil circuit when the HVAC system is operating in a heating mode. 
   
     
     
         17 . The HVAC system of  claim 16 , further comprising, for each coil circuit of the plurality of circuits, a manifold line fluidly coupling the coil circuit to a compressor of the HVAC system. 
     
     
         18 . The HVAC system of  claim 16 , wherein the first heat exchange coil is an outdoor coil, and second heat exchange coil is an indoor coil. 
     
     
         19 . The HVAC system of  claim 16 , further comprising, for each coil circuit of the plurality of coil circuits other than the first coil circuit, a conduit coupling the coil circuit to the expansion valve. 
     
     
         20 . The HVAC system of  claim 16 , further comprising a liquid line fluidly coupling the expansion valve and the expansion valve bypass line to the second heat exchange coil.