Heat Exchanger Element and a Water Heater and Heat Pump Utilizing Same

Abstract

A heat exchanger element ( 30 ) formed from an inner copper tube ( 32 ) and an outer copper tube ( 34 ). The entire outer surface of the inner tube ( 32 ) is substantially in contact with the entire inner surface of the outer tube ( 34 ).

1 . A method of forming a heat exchanger element, the method comprising the following steps:
 a. drawing a first and a second copper tube, the first tube having an outer diameter less than the internal diameter of the second tube;   b. inserting the first tube into the second tube;   c. passing the tubes through a roll former adapted to crush the second tube onto the first tube, such that the entire outer surface of the first tube is substantially in contact with the entire inner surface of the second tube.   d. annealing the crushed tubes;   e. bending the tubes into a desired configuration; and   f. annealing the bent tubes.   
   
   
       2 . The method as claimed in  claim 1 , wherein step e. includes bending the tubes into a generally cylindrical shape. 
   
   
       3 . The method as claimed in  claim 2 , including the step of forming the cylindrical walls from spiraled tubes. 
   
   
       4 . The method as claimed in  claim 1 , wherein step a. includes drawing the second tube with internal rifling or grooves. 
   
   
       5 . A heat exchanger clement formed by the method as defined in  claim 1 . 
   
   
       6 . A water heater including a tank and a heat exchanger element according to  claim 5 . 
   
   
       7 . A heat pump circuit comprising an evaporator coil; a compressor, a condenser coil in a heat exchanging relationship with a body of water, and a thermostatic expansion valve (TX valve), the circuit adapted to hold a charge of refrigerant,
 wherein the condenser coil is in the form of a heat exchanger element according to  claim 5 .