Exhaust gas heat exchanger for cogeneration system

Abstract

An exhaust gas heat exchanger for a cogeneration system is disclosed which includes exhaust gas discharge tubes each including a bellows tube portion formed at at least a portion of the exhaust gas discharge tube to enable the exhaust gas discharge tube to be thermally expanded and shrunken, so that it is possible to prevent the exhaust gas discharge tube from being damaged due to repeated thermal expansion and shrinkage thereof caused by hot exhaust gas passing through the exhaust gas discharge tube. Accordingly, an enhancement in durability and reliability is achieved.

1 . An exhaust gas heat exchanger for a cogeneration system comprising: 
 a shell;    an exhaust gas path which is defined in the shell to guide exhaust gas to pass through the shell; and    a refrigerant path which is defined in the shell to guide a refrigerant to pass through the shell such that the refrigerant heat-exchanges with the exhaust gas path,    wherein the exhaust gas path includes exhaust gas passages respectively defined by exhaust gas discharge tubes each including a bellows tube portion formed at at least a portion of the exhaust gas discharge tube to enable the exhaust gas discharge tube to be thermally expanded and shrunken.    
   
   
       2 . The exhaust gas heat exchanger according to  claim 1 , wherein the bellows tube portion is longitudinally pleated in a longitudinal direction of the exhaust gas discharge tube.  
   
   
       3 . The exhaust gas heat exchanger according to  claim 1 , wherein the bellows tube portion is pleated in a circumferential direction of the exhaust gas discharge tube.  
   
   
       4 . The exhaust gas heat exchanger according to  claim 2 , wherein the bellows tube portion includes circular pleats.  
   
   
       5 . The exhaust gas heat exchanger according to  claim 2 , wherein the bellows tube portion includes a spiral pleat.  
   
   
       6 . The exhaust gas heat exchanger according to  claim 4 , further comprising: 
 an exhaust gas inlet and an exhaust gas outlet respectively formed at opposite ends of the shell to allow the exhaust gas to pass through the shell,    wherein the exhaust gas discharge tubes connect the exhaust gas inlet and the exhaust gas outlet.    
   
   
       7 . The exhaust gas heat exchanger according to  claim 6 , wherein: 
 each of the exhaust gas discharge tubes further includes a constant-diameter cylindrical tube portion;    the bellows tube portion is arranged toward the exhaust gas inlet; and    the constant-diameter cylindrical tube portion is arranged toward the exhaust gas outlet.    
   
   
       8 . The exhaust gas heat exchanger according to  claim 6 , further comprising: 
 a refrigerant inlet and a refrigerant outlet which are formed through a peripheral wall of the shell.    
   
   
       9 . The exhaust gas heat exchanger according to  claim 8 , further comprising: 
 a first isolation plate and a second isolation plate which are arranged in the shell to isolate the exhaust gas inlet and the exhaust gas outlet from each other, thereby defining the refrigerant path.    
   
   
       10 . The exhaust gas heat exchanger according to  claim 8 , further comprising: 
 at least one flow guide adapted to change the refrigerant path.    
   
   
       11 . A cogeneration system comprising: 
 an engine;    a generator which is driven by the engine to generate electricity;    an exhaust gas heat exchanger which is arranged in an exhaust gas discharge conduit extending from the engine to recover heat from exhaust gas discharged from the engine; and    an air conditioner which receives the recovered heat from the exhaust gas heat exchanger,    wherein the exhaust gas heat exchanger includes a shell, and exhaust gas discharge tubes arranged in the shell, each of the exhaust gas discharge tubes including a bellows tube portion formed at at least a portion of the exhaust gas discharge tube.    
   
   
       12 . The cogeneration system according to  claim 11 , wherein the bellows tube portion is longitudinally pleated in a longitudinal direction of the exhaust gas discharge tube.  
   
   
       13 . The cogeneration system according to  claim 11 , wherein the bellows tube portion is pleated in a circumferential direction of the exhaust gas discharge tube.  
   
   
       14 . The cogeneration system according to  claim 12 , wherein the bellows tube portion includes circular pleats.  
   
   
       15 . The cogeneration system according to  claim 12 , wherein the bellows tube portion includes a spiral pleat.  
   
   
       16 . The cogeneration system according to  claim 14 , wherein: 
 the exhaust gas heat exchanger further comprises an exhaust gas inlet and an exhaust gas outlet respectively formed at opposite ends of the shell to allow the exhaust gas to pass through the shell,    the exhaust gas discharge tubes connect the exhaust gas inlet and the exhaust gas outlet.    
   
   
       17 . The cogeneration system according to  claim 16 , wherein: 
 each of the exhaust gas discharge tubes further includes a constant-diameter cylindrical tube portion;    the bellows tube portion is arranged toward the exhaust gas inlet; and    the constant-diameter cylindrical tube portion is arranged toward the exhaust gas outlet.    
   
   
       18 . The cogeneration system according to  claim 16 , wherein the exhaust gas heat exchanger further comprises a refrigerant inlet and a refrigerant outlet which are formed through a peripheral wall of the shell.  
   
   
       19 . The cogeneration system according to  claim 18 , wherein the exhaust gas heat exchanger further comprises a first isolation plate and a second isolation plate which are arranged in the shell to isolate the exhaust gas inlet and the exhaust gas outlet from each other, thereby defining the refrigerant path.  
   
   
       20 . The cogeneration system according to  claim 18 , wherein the exhaust gas heat exchanger further comprises at least one flow guide adapted to change the refrigerant path.