Method and apparatus of forming heat exchanger tubes

Abstract

A heat exchange tube for a refrigerant-flooded evaporator includes a tube body and a plurality of channels for conveying a cooling medium therethrough located in the tube body. One or more outer wall textural elements are included at the outer wall of the tube body to improve thermal energy transfer between the cooling medium and a volume of boiling refrigerant. A method of forming a heat exchange tube for a refrigerant-flooded evaporator includes urging a billet into an extrusion section and forming the billet into two tube halves including an outer wall and an inner wall having a plurality of channel halves. A textural element is formed at one or more of the outer wall and the inner wall via one or more rotating dies, and the two tube halves are joined to form the heat exchange tube.

1 . A heat exchange tube for a refrigerant-flooded evaporator comprising:
 a tube body;   a plurality of channels for conveying a cooling medium therethrough disposed in the tube body; and   one or more outer wall textural elements at the outer wall of the tube body to improve thermal energy transfer between the cooling medium and a volume of boiling refrigerant.   
     
     
         2 . The heat exchange tube of  claim 1 , wherein the outer wall textural elements comprise one or more ridges. 
     
     
         3 . The heat exchange tube of  claim 1 , wherein the outer wall textural elements comprise one or more pockets. 
     
     
         4 . The heat exchange tube of  claim 1 , wherein the outer wall textural elements are configured to improve nucleate boiling of the refrigerant. 
     
     
         5 . The heat exchange tube of  claim 1 , further comprising one or more inner wall textural elements disposed at at least one inner wall of the plurality of channels. 
     
     
         6 . The heat exchange tube of  claim 5 , wherein the one or more inner wall textural elements comprise one or more of dimples, grooves or fins. 
     
     
         7 . The heat exchange tube of  claim 1 , comprising about 2 to about 20 channels disposed in the tube body. 
     
     
         8 . The heat exchange tube of  claim 7 , comprising about 10 to about 16 channels disposed in the tube body. 
     
     
         9 . The heat exchange tube of  claim 7 , comprising about 4 to about 6 channels disposed in the tube body. 
     
     
         10 . A refrigerant-flooded evaporator comprising:
 a volume of two-phase refrigerant;   a plurality of heat exchange tubes submerged in the volume of refrigerant, at least one heat exchange tube of the plurality of heat exchange tubes including:   a tube body;   a plurality of channels having a cooling medium flowing therethrough disposed in the tube body; and   one or more outer wall textural elements at the outer wall of the tube body to improve thermal energy transfer between the cooling medium and the volume of two-phase refrigerant.   
     
     
         11 . The evaporator of  claim 10 , wherein the outer wall textural elements comprise one or more ridges. 
     
     
         12 . The evaporator of  claim 10 , wherein the outer wall textural elements comprise one or more pockets. 
     
     
         13 . The evaporator of  claim 10 , wherein the outer wall textural elements are configured to improve nucleate boiling of the refrigerant. 
     
     
         14 . The evaporator of  claim 10 , further comprising one or more inner wall textural elements disposed at at least one inner wall of the plurality of channels. 
     
     
         15 . A method of forming a heat exchange tube for a refrigerant-flooded evaporator comprising:
 urging a billet into an extrusion section;   forming the billet into two tube halves including an outer wall and an inner wall having a plurality of channel halves;   forming a textural element at one or more of the outer wall and the inner wall via one or more rotating dies; and   joining the two tube halves to form the heat exchange tube.   
     
     
         16 . The method of  claim 15  further comprising joining the tube halves by solid state diffusion bonding, brazing, or other suitable joining technique. 
     
     
         17 . The method of  claim 15 , further comprising heating the billet to a selected temperature before extruding. 
     
     
         18 . The method of  claim 15 , wherein the billet comprises one of copper, copper alloy, aluminum or aluminum alloy. 
     
     
         19 . The method of  claim 15 , wherein a textural element is formed on the outer wall of the heat exchange tube after joining of the two tube halves.