Flow circuitry and valving for reversible hvac heat exchange configurations

Abstract

An HVAC system can include a multiport valve for controlling refrigerant circulation that permits refrigerant flow in a first direction through an interior heat exchanger and in a first direction through an auxiliary heat exchanger and at least one additional configuration in which refrigerant flows in a second direction through at least one of the interior heat exchanger and the auxiliary heat exchanger. The at least one configuration can include a second configuration in which refrigerant flows in the first direction through the interior heat exchanger and in the second direction through the auxiliary heat exchanger and a third configuration in which refrigerant flows in the second direction through the interior heat exchanger and the auxiliary heat exchanger.

1 . An HVAC system comprising:
 an interior heat exchanger that receives an air stream, facilitates heat transfer between the air stream and a refrigerant, and discharges the air stream;   an auxiliary heat exchanger that receives the air stream discharged from the interior heat exchanger and facilitates further heat transfer between the air stream and the refrigerant, and dischargers the air stream; and   a multiport valve that controls refrigerant circulation through the interior heat exchanger and the auxiliary heat exchanger, the multiport valve having:
 a first configuration in which refrigerant flows in a first refrigerant flow direction through the interior heat exchanger and in a first refrigerant flow direction through the auxiliary heat exchanger, wherein the first refrigerant flow direction is a cross-counter flow direction relative to airflow through a respective heat exchanger; and 
 at least one additional configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger, wherein the second refrigerant flow direction is a cross-parallel flow direction relative to airflow through the respective heat exchanger. 
   
     
     
         2 . The HVAC system of  claim 1  wherein the at least one configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger further comprises:
 a second configuration in which refrigerant flows in the first refrigerant flow direction through the interior heat exchanger and in the second refrigerant flow direction through the auxiliary heat exchanger; and 
 a third configuration in which refrigerant flows in the second refrigerant flow direction through the interior heat exchanger and the auxiliary heat exchanger. 
 
     
     
         3 . The HVAC system of  claim 2  wherein the first configuration is a heating configuration, the second configuration is a dehumidifying configuration, and the third configuration is a cooling configuration. 
     
     
         4 . The HVAC system of  claim 3  wherein in the first/heating configuration refrigerant flows first through the auxiliary heat exchanger and then through the interior heat exchanger and in the third/cooling configuration refrigerant flows first through the interior heat exchanger and then through the auxiliary heat exchanger. 
     
     
         5 . The HVAC system of  claim 1  wherein the multiport valve has at least one configuration in which refrigerant flow bypasses at least one of the interior heat exchanger and the auxiliary heat exchanger. 
     
     
         6 . A multiport valve for controlling refrigerant circulation through an interior heat exchanger and an auxiliary heat exchanger of an HVAC system, the multiport valve having:
 a first configuration that permits refrigerant flow in a first refrigerant flow direction through the interior heat exchanger and in a first refrigerant flow direction through the auxiliary heat exchanger; and   at least one additional configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger.   
     
     
         7 . The multiport valve of  claim 6  wherein the at least one configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger further comprises:
 a second configuration in which refrigerant flows in the first refrigerant flow direction through the interior heat exchanger and in the second refrigerant flow direction through the auxiliary heat exchanger; and 
 a third configuration in which refrigerant flows in the second refrigerant flow direction through the interior heat exchanger and the auxiliary heat exchanger. 
 
     
     
         8 . The multiport valve of  claim 7  wherein the multiport valve has at least six ports. 
     
     
         9 . The multiport valve of  claim 8  wherein in the first configuration a hot gas port is coupled to a first port of the auxiliary heat exchanger, a second port of the auxiliary heat exchanger is coupled to a first port of the interior heat exchanger, and a second port of the interior heat exchanger is coupled to a liquid refrigerant line of the HVAC system. 
     
     
         10 . The multiport valve of  claim 9  wherein the first configuration is a heating configuration. 
     
     
         11 . The multiport valve of  claim 8  wherein in the second configuration, a hot gas port is coupled to a first port of the auxiliary heat exchanger, a suction line is coupled to a second port of the auxiliary heat exchanger, a liquid refrigerant line is coupled to a first port of the interior heat exchanger, and a second port of the interior heat exchanger is coupled to an expansion valve of the HVAC system, thereby reversing refrigerant flow through the interior heat exchanger relative to the first configuration while maintaining refrigerant flow in the first refrigerant flow direction through the auxiliary heat exchanger. 
     
     
         12 . The multiport valve of  claim 11  wherein the second configuration is a dehumidifying configuration. 
     
     
         13 . The multiport valve of  claim 8  wherein in the third configuration, a second port of the interior heat exchanger is coupled to an expansion valve of the HVAC system, a first port of the interior heat exchanger is coupled to a second port of the auxiliary heat exchanger, and a first port of the auxiliary heat exchanger is coupled to a suction line, thereby reversing refrigerant flow through the interior heat exchanger and the auxiliary heat exchanger relative to the first configuration. 
     
     
         14 . The multiport valve of  claim 13  wherein the third configuration is a cooling configuration. 
     
     
         15 . The multiport valve of  claim 6  further having at least one configuration in which refrigerant flow bypasses at least one of the interior heat exchanger and the auxiliary heat exchanger. 
     
     
         16 . A method of operating an HVAC system to achieve a plurality of operating modes, the method comprising:
 actuating a multiport valve to a first position corresponding to a first operating mode, the first position permitting refrigerant flow in a first refrigerant flow direction through an interior heat exchanger that also receives an airstream from an interior space and in the first refrigerant flow direction through an auxiliary heat exchanger that receives the airstream from the interior heat exchanger and returns it to the interior space;   actuating the multiport valve to at least one other position corresponding to at least one other operating mode, the at least one other position reversing refrigerant flow to a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger.   
     
     
         17 . The method of  claim 16  wherein actuating the multiport valve to at least one other position corresponding to at least one other operating mode, the at least one other position reversing refrigerant flow to a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger further comprises:
 actuating the multiport valve to a second position corresponding to a second operating mode, the second position reversing refrigerant flow through the interior heat exchanger; and 
 actuating the multiport valve to a third position corresponding to a third operating mode, the third position reversing refrigerant flow through the interior heat exchanger and the auxiliary heat exchanger. 
 
     
     
         18 . The method of  claim 17  wherein the first operating mode is a heating mode, the second operating mode is a dehumidifying mode, and the third operating mode is a cooling mode. 
     
     
         19 . The method of  claim 18  wherein the first refrigerant flow direction is a cross-counter flow direction relative to airflow through a respective heat exchanger and reversed refrigerant flow is in a cross-parallel flow direction relative to airflow through a respective heat exchanger.