Spiral flat-tube heat exchanger

Abstract

A spiral flat tube heat exchanger comprising a first flat tube and a second flat tube thermally coupled to the first flat tube, the first flat tube and the second flat tube forming substantially concentric spirals. A first fluid flows through the first flat tube in a first flow direction, and second fluid flows through the second flat tube in a second flow direction. The flat tubes preferably contain microchannels to increase heat transfer efficiency.

1 . A heat exchanger comprising:
 a first flat tube; and   a second flat tube thermally coupled to the first flat tube,   wherein the first flat tube forms a first spiral and the second flat tube forms a second spiral, the first spiral and the second spiral being substantially concentric, and   wherein a first fluid flows through the first spiral in a first flow direction and a second fluid flows through the second spiral in a second flow direction.   
   
   
       2 . The heat exchanger of  claim 1 , wherein the first flat tube and the second flat tube comprise flat tubes having microchannels. 
   
   
       3 . The heat exchanger of  claim 1 , wherein the first flat tube and the second flat tube each have an obround cross section. 
   
   
       4 . The heat exchanger of  claim 1 , wherein the first fluid is water and the second fluid is a refrigerant. 
   
   
       5 . The heat exchanger of  claim 1 , wherein the first flow direction is opposite the second flow direction. 
   
   
       6 . The heat exchanger of  claim 1 , wherein the first flow direction is substantially parallel with the second flow direction. 
   
   
       7 . The heat exchanger of  claim 1 , further comprising a plurality of first collectors in fluid communication with the first flat tube and a plurality of second collectors in fluid communication with the second flat tube. 
   
   
       8 . The heat exchanger of  claim 7 , wherein at least one of the plurality of first collectors and at least one of the plurality of second collectors is disposed substantially near a central area of the first and second spirals. 
   
   
       9 . The heat exchanger of  claim 8 , wherein at least one of the plurality of first collectors and at least one of the plurality of second collectors is disposed on a periphery of the heat exchanger. 
   
   
       10 . The heat exchanger of  claim 1 , wherein the first flat tube contacts the second flat tube along substantially an entire length of the first flat tube. 
   
   
       11 . The heat exchanger of  claim 1 , wherein the first flat tube and second flat tube comprise a material selected from the group consisting of aluminum, copper, plastic, and any combination thereof. 
   
   
       12 . The heat exchanger of  claim 1 , wherein the first flat tube and the second flat tube are joined by a brazing process. 
   
   
       13 . The heat exchanger of  claim 1 , wherein the first flat tube and the second flat tube brought into thermal contact using a process selected from the group consisting of gluing, applying a conductive grease, mechanical bonding, and any combination thereof. 
   
   
       14 . The heat exchanger of  claim 1 , wherein the first flat tube comprises a plurality of flat tubes. 
   
   
       15 . The heat exchanger of  claim 13 , wherein the second flat tube comprises a plurality of flat tubes. 
   
   
       16 . A heat exchanger having a plurality of modules, each module comprising:
 at least two collectors; and   a plurality of microchannel flat tubes positioned vertically between the at least two collectors and each having a longitudinal axis, wherein the longitudinal axis of each of the plurality of microchannel flat tubes is substantially collinear with the longitudinal axis of each of the other microchannel flat tubes.   
   
   
       17 . The heat exchanger of  claim 15 , wherein the plurality of microchannel flat tubes are in thermal contact with each other. 
   
   
       18 . The heat exchanger of  claim 15 , wherein the plurality of modules wrap around each other in a spiral configuration. 
   
   
       19 . A method of making a spiral heat exchanger, the method comprising:
 providing a first module having a first inlet collector connected to a first outlet collector by a first flat tube;   providing a second module having a second inlet collector connected to a second outlet collector by a second flat tube;   positioning the first module adjacent to the second module with the first inlet collector in proximity to the second outlet collector and the first outlet collector in proximity to the second inlet collector; and   rotating the first outlet collector and the second inlet collector together in the same direction while holding the first inlet collector and the second outlet collector in a fixed position so as to deform the first flat tube and second flat tube to form two substantially concentric spirals.   
   
   
       20 . The method of  claim 18 , further comprising the step of brazing the entire heat exchanger. 
   
   
       21 . (canceled)