Heat Exchange System

Abstract

A heat exchange system operating on a vapor compression cycle is capable of operating in both an air conditioning mode and a heat pump mode. The heat exchange system can include a parallel flow heat exchanger that operates as a condenser in one mode and as an evaporator in the other mode. The heat exchanger can include a first, second, and third fluid manifold, with fluid conduits connecting the first and second fluid manifolds, and with additional fluid conduits connecting the second and third fluid manifolds. The heat exchanger can be configured to transfer heat between a working fluid traveling through the fluid conduits and another fluid, such as an air flow passing over the fluid conduits.

What is claimed is: 
     
         1 . A heat exchange system capable of operating both an air conditioning mode and a heat pump mode, comprising:
 a compressor operable to compress and circulate a refrigerant through the heat exchange system;   an expansion device operable to expand the refrigerant from a high pressure liquid state to a low pressure two-phase state;   a reversing valve operable to direct the flow of refrigerant through the heat exchange system, the reversing valve having a first port fluidly connected to an inlet of the compressor to direct the flow of refrigerant thereto, a second port fluidly connected to an outlet of the compressor to receive the flow of refrigerant therefrom, a third port, and a fourth port;   a first fluid flow path extending between the third port of the reversing valve and a first port of the expansion device;   a second fluid flow path extending between the fourth port of the reversing valve and a second port of the expansion device, the second fluid flow path including a first branch portion and a second branch portion arranged fluidly in parallel with the first branch portion; and   a heat exchanger having a first plurality of fluid conduits and a second plurality of fluid conduits, wherein the first plurality of fluid conduits and the second plurality of fluid conduits provide parallel flow paths for refrigerant flowing along the first branch portion and wherein the first plurality of fluid conduits and the second plurality of fluid conduits provide a series flow path for refrigerant flowing along the second branch portion.   
     
     
         2 . The heat exchange system of  claim 1 , wherein the flow of refrigerant is directed along the first branch portion but not the second branch portion when the heat exchange system is operating in the air conditioning mode and wherein the flow of refrigerant is directed along the second branch portion but not the first branch portion when the heat exchange system is operating in the heat pump mode. 
     
     
         3 . The heat exchange system of  claim 2 , further comprising:
 at least one flow control device arranged along the first branch portion to allow the flow of refrigerant when the heat exchange system is operating in the air conditioning mode and to block the flow of refrigerant when the heat exchange system is operating in the heat pump mode; and   at least one flow control device arranged along the second branch portion to block the flow of refrigerant when the heat exchange system is operating in the air conditioning mode and to allow the flow of refrigerant when the heat exchange system is operating in the heat pump mode.   
     
     
         4 . The heat exchange system of  claim 1 , wherein the heat exchanger comprises:
 a first fluid manifold arranged at an end of the heat exchanger;   a second fluid manifold arranged at an end of the heat exchanger; and   a third fluid manifold arranged at an end of the heat exchanger, wherein the first plurality of fluid conduits extend between the first fluid manifold and the second fluid manifold and wherein the second plurality of fluid conduits extend between the second fluid manifold and the third fluid manifold.   
     
     
         5 . The heat exchange system of  claim 4 , wherein the heat exchanger comprises a fluid port connected to the second fluid manifold, the flow of refrigerant passing through said fluid port when the heat exchange system is operating in the air conditioning mode but not when the heat exchange system is operating in the heat pump mode. 
     
     
         6 . The heat exchange system of  claim 4 , wherein the heat exchanger further comprises a fluid distributor arranged within the second fluid manifold and coupled to the fluid port connected to the second fluid manifold. 
     
     
         7 . The heat exchange system of  claim 4 , wherein the heat exchanger comprises a first cylindrical header tube containing the first fluid manifold and the third fluid manifold, and a second cylindrical header tube containing the second fluid manifold. 
     
     
         8 . The heat exchange system of  claim 7 , wherein the first fluid manifold and the third fluid manifold are separated by a baffle provided within the first cylindrical header tube. 
     
     
         9 . The heat exchange system of  claim 4 , wherein the heat exchanger comprises a first fluid port connected to the first fluid manifold and a second fluid port connected to the third fluid manifold, wherein the second fluid port operates as an outlet port for the flow of refrigerant in both the air conditioning mode and the heat pump mode and wherein the first fluid port operates as an inlet port for the refrigerant in the heat pump mode and as an outlet port for the refrigerant in the air conditioning mode. 
     
     
         10 . The heat exchange system of  claim 9 , wherein the heat exchanger further comprises a third fluid port connected to the second fluid manifold, the third fluid port operating as an inlet port for the refrigerant in the air conditioning mode. 
     
     
         11 . The heat exchange system of  claim 10 , wherein the heat exchanger further comprises a fluid distributor arranged within the second fluid manifold and coupled to the third fluid port. 
     
     
         12 . The heat exchange system of  claim 4 , wherein the first fluid manifold and the third fluid manifold are arranged at the same end of the heat exchanger and wherein the second fluid manifold is arranged at an opposite end of the heat exchanger. 
     
     
         13 . The heat exchange system of  claim 4 , wherein the first fluid manifold, the second fluid manifold, and the third fluid manifold are arranged at the same end of the heat exchanger.