Heat exchanger for residential hvac applications

Abstract

A heat exchanger is provided including a first header and a second header and a plurality of heat exchange tube arranged in spaced parallel relationship and fluidly coupling the first and second header. A flow restricting element defining a first volume and a second volume is positioned within one of the first and second header. The heat exchanger has a multi-pass configuration such that a first portion of the plurality of heat exchange tubes are coupled to the first volume and form a first fluid pass of the heat exchanger and a second portion of the plurality of heat exchange tubes are coupled to the second volume and form a second fluid pass of the heat exchanger. During operation, the heat transfer fluid conveyed through the first volume has a first saturation temperature and the heat transfer fluid conveyed through the second volume has a different second saturation temperature.

What is claimed is: 
     
         1 . A heat exchanger, comprising:
 a first header;   a second header, wherein at least one of the first header and the second header comprise a flow restricting element therein defining a first volume and a second volume; and   a plurality of heat exchange tubes arranged in spaced parallel relationship and fluidly coupling the first header and second header;   wherein the heat exchanger has a multi-pass configuration such that a first portion of the plurality of heat exchange tubes are coupled to the first volume and form a first fluid pass of the heat exchanger and a second portion of the plurality of heat exchange tubes are coupled to the second volume and form a second fluid pass of the heat exchanger, wherein during operation a heat transfer fluid conveyed through the first volume has a first saturation temperature and the heat transfer fluid conveyed through the second volume has a second saturation temperature, wherein the first saturation temperature and the second saturation temperature are different.   
     
     
         2 . The heat exchanger according to  claim 1 , wherein a difference between the second saturation temperature and the first saturation temperature exceeds normal temperature variation within the at least one of the first header and second header. 
     
     
         3 . The heat exchanger according to  claim 1 , wherein the flow restricting element imparts a pressure drop on the heat transfer fluid conveyed there through during operation, causing the first saturation temperature and the second saturation temperature to be different. 
     
     
         4 . The heat exchanger according to  claim 3 , wherein the pressure drop is between about 1 psi and about 12 psi. 
     
     
         5 . The heat exchanger according to  claim 3 , wherein the pressure drop is about 6 psi. 
     
     
         6 . The heat exchanger according to  claim 3 , wherein the flow restricting element comprises an orifice. 
     
     
         7 . The heat exchanger according to  claim 6 , wherein a cross-sectional area of the orifice is between about 3% and about 30% of a cross-sectional area of the at least one of the first header and the second header in which it is disposed. 
     
     
         8 . The heat exchanger according to  claim 6 , wherein a distributor fluidly coupled to the orifice is arranged within the second volume and is adjacent at least the second portion of the plurality of heat exchange tubes. 
     
     
         9 . The heat exchanger according to  claim 1 , further comprising a porous insert positioned within the second volume adjacent at least the second portion of the plurality of heat exchange tubes, the porous insert being configured to restrict a fluid flow path between the first fluid pass and the second fluid pass. 
     
     
         10 . The heat exchanger according to  claim 1 , wherein the flow restricting element comprises a flow control valve, the flow control valve being movable to adjust a parameter of a fluid flow path between the first fluid pass and the second fluid pass. 
     
     
         11 . The heat exchanger according to  claim 1 , wherein the plurality of heat exchange tubes are microchannel tubes. 
     
     
         12 . The heat exchanger according to  claim 1 , wherein the first header comprises one or more partitions disposed therein and defining two or more discrete fluid volumes. 
     
     
         13 . The heat exchanger according to  claim 1 , wherein the first header comprises two baffles forming three first header inner volumes and the second header comprises two flow restricting elements forming a first, second, and third second header volume. 
     
     
         14 . The heat exchanger according to  claim 13 , wherein during operation a heat transfer fluid conveyed through the first volume has a first saturation temperature and the heat transfer fluid conveyed through the third volume has a third saturation temperature, wherein the first saturation temperature and the third saturation temperature are different. 
     
     
         15 . The heat exchanger according to  claim 14 , wherein the second saturation temperature and the third saturation temperature are generally identical. 
     
     
         16 . The heat exchanger according to  claim 14 , wherein the second saturation temperature and the third saturation temperature are distinct.