Internal heat exchanger

Abstract

A heat exchanger includes an outer tube and an inner tube coaxially arranged within the outer tube. Both of the outer tube and the inner tube include a fluid channel formed therein. A first fluid flows through the fluid channel of the outer tube, and a second fluid, in heat exchange relationship with the first fluid, flows through the fluid channel of the inner tube. At least one heat conductive feature is formed between the outer tube and the inner tube, and on an inner surface of the inner tube to maximize a heat exchange between the fluids.

1 . A heat exchanger, comprising:
 an outer tube including at least one fluid channel formed therein, wherein the at least one fluid channel receives a first fluid therein; and   a first inner tube arranged within the outer tube, the first inner tube including at least one fluid channel formed therein, wherein the at least one fluid channel receives a second fluid therein, and wherein a cross-sectional flow area of the at least one fluid channel of the first inner tube is greater than a cross-sectional flow area of the at least one fluid channel of the outer tube.   
     
     
         2 . The heat exchanger according to  claim 1 , further comprising at least one heat conductive feature formed between the outer tube and the first inner tube. 
     
     
         3 . The heat exchanger according to  claim 1 , wherein the first inner tube includes at least one heat conductive feature formed on an inner surface thereof. 
     
     
         4 . The heat exchanger according to  claim 1 , further comprising a second inner tube arranged within the first inner tube, the second inner tube including at least one fluid channel formed therein. 
     
     
         5 . The heat exchanger according to  claim 4 , further comprising at least one heat conductive feature formed between the first inner tube and the second inner tube. 
     
     
         6 . The heat exchanger according to  claim 1 , wherein the first fluid is a liquid refrigerant and the second fluid is a vapor refrigerant. 
     
     
         7 . A heat exchanger, comprising:
 an outer tube including at least one fluid channel formed therein, wherein the at least one fluid channel receives a first fluid therein;   a first inner tube arranged within the outer tube, the first inner tube including at least one fluid channel formed therein, wherein the at least one fluid channel receives a second fluid therein, and wherein a cross-sectional flow area of the at least one fluid channel of the first inner tube is greater than a cross-sectional flow area of the at least one fluid channel of the outer tube; and   a first plurality of heat conductive features formed on an inner surface of the first inner tube.   
     
     
         8 . The heat exchanger according to  claim 7 , wherein the heat conductive features are circumferentially spaced apart at a predetermined interval. 
     
     
         9 . The heat exchanger according to  claim 7 , wherein a thickness of the heat conductive features gradually decreases at ends of the heat exchanger. 
     
     
         10 . The heat exchanger according to  claim 7 , wherein a height of the heat conductive features gradually decreases at ends of the heat exchanger. 
     
     
         11 . The heat exchanger according to  claim 7 , further comprising a first plurality of heat conductive features formed between the outer tube and the first inner tube. 
     
     
         12 . The heat exchanger according to  claim 11 , wherein a number of the heat conductive features formed between the outer tube and the first inner tube is greater than a number of the heat conductive features formed on the inner surface of the first inner tube. 
     
     
         13 . The heat exchanger according to  claim 7 , further comprising a second plurality of heat conductive features formed on an inner surface of the first inner tube, wherein a height of the second plurality of heat conductive features formed on the inner surface of the first inner tube is less than a height of the first plurality of heat conductive features formed thereon. 
     
     
         14 . The heat exchanger according to  claim 13 , further comprising a third plurality of heat conductive features formed on an inner surface of the first inner tube, wherein a height of the third plurality of heat conductive features formed on the inner surface of the first inner tube is less than a height of the second plurality of heat conductive features formed thereon. 
     
     
         15 . The heat exchanger according to  claim 14 , wherein a number of the heat conductive features formed between the outer tube and the first inner tube is less than a number of the heat conductive features formed on the inner surface of the first inner tube. 
     
     
         16 . A heat exchanger, comprising:
 an outer tube including at least one fluid channel formed therein, wherein the at least one fluid channel receives a first fluid therein;   a first inner tube arranged within the outer tube, the first inner tube including at least one fluid channel formed therein, wherein the at least one fluid channel receives a second fluid therein;   a second inner tube arranged within the first inner tube, the second inner tube including at least one fluid channel formed therein, wherein the at least one fluid channel receives the second fluid therein; and   a plurality of heat conductive features formed between the first inner tube and the second inner tube.   
     
     
         17 . The heat exchanger according to  claim 16 , wherein a cumulative cross-sectional flow area of the fluid channels of the inner tubes is greater than a cumulative cross-sectional flow area of the at least one fluid channel of the outer tube. 
     
     
         18 . The heat exchanger according to  claim 16 , wherein the heat conductive features formed between the first inner tube and the second inner tube are circumferentially spaced apart at a predetermined interval. 
     
     
         19 . The heat exchanger according to  claim 16 , further comprising a first plurality of heat conductive features formed between the outer tube and the first inner tube. 
     
     
         20 . The heat exchanger according to  claim 19 , wherein a number of the heat conductive features formed between the outer tube and the first inner tube is greater than a number of the heat conductive features formed on the inner surface of the first inner tube.