Improved water heater

Abstract

This invention relates to a water heater comprising a water tank ( 1 ) having a wall ( 2 ) formed from material having heat transfer properties and a cold water inlet ( 5 ) adjacent one end of the tank. A tube ( 8 ), adapted to carry a refrigerant fluid, is secured externally about the tank wall ( 2 ). Heat-conductive material is provided along the length of the tube, with the tube and the heat-conductive material in heat-conductive contact with the external surface of the wall of the tank to transfer heat from condensation of the refrigerant fluid in the tube through the wall to the water contained in the tank ( 1 ). An evaporator ( 15 ) is positioned so as to be exposed to ambient conditions for absorbing heat energy from the ambient conditions. The evaporator is provided with a passage for carrying the refrigerant fluid whereby the fluid may be heated by the ambient conditions. A compressor ( 12 ) is connected to the passage and to the tube ( 8 ) so as to circulate the refrigerant fluid through the tube and to the evaporator ( 15 ).

1 - 14 . (Cancelled)  
     
     
         15 . A water heater comprising: 
 a water tank having a wall formed from material having heat transfer properties; a cold water inlet adjacent one end of the tank;    a tube adapted to carry a refrigerant fluid secured externally about said tank wall by mechanical means;    a non-bonding, heat-conductive material applied in a paste form along the length of said tube; said heat-conductive material injected along the length of the tube at the interface between the tube and said tank wall;    said tube and heat-conductive material in heat-conductive contact said wall of said tank to transfer heat from condensation of said refrigerant fluid in said tube through said wall to the water contained in the tank;    an evaporator positioned to be exposed to ambient conditions for absorbing heat energy from said ambient conditions, and having a passage for carrying the refrigerant fluid whereby said fluid may be heated by said ambient conditions; and    a compressor connected to said passage and to said tube to circulate refrigerant fluid through said tube and to said evaporator.    
     
     
         16 . The water heater as claimed in  claim 15 , wherein the tube is helically wound around said tank.  
     
     
         17 . The water heater as claimed in  claim 15 , wherein the pitch of the winding of the tube around the tank is varied.  
     
     
         18 . The water heater as claimed in  claim 16 , wherein the pitch of the winding of the tube around the tank is varied.  
     
     
         19 . The water heater as claimed in  claim 17 , wherein the pitch of the windings of the tube varies such that the spacing between adjacent windings increases towards the top of the tank.  
     
     
         20 . The water heater as claimed in  claim 16 , wherein the tube is substantially D-shaped in cross-section.  
     
     
         21 . The water heater as claimed in  claim 15 , wherein said heat-conductive material is substantially coextensive with the length of the tube.  
     
     
         22 . The water heater as claimed in  claim 19 , wherein said heat-conductive material is substantially coextensive with the length of the tube.  
     
     
         23 . The water heater as claimed in  claim 16 , wherein the tube is formed from copper or a copper-based alloy.  
     
     
         24 . The water heater as claimed in  claim 19 , wherein the tube is mechanically fastened at one or more locations to the wall of the tank.  
     
     
         25 . The water heater as claimed in  claim 19 , wherein two or more tubes are wound around the tank to carry said refrigerant fluid.  
     
     
         26 . The water heater as claimed in  claim 24 , wherein two or more tubes are wound around the tank to carry said refrigerant fluid.  
     
     
         27 . A method of making a water heater comprising the steps of: 
 attaching one end of a tube to an external surface of a water tank, winding the tube around the external surface of said tank, and injecting a non-bonding, heat-conductive paste along the length of said tube at the interface between the tube and said tank wall.    
     
     
         28 . The method as claimed in  claim 27 , wherein the tube is wound around the external surface of the tank.  
     
     
         29 . The method as claimed in  claim 28 , wherein the tube is wound around the external surface of the tank under a predetermined tension.  
     
     
         30 . The method as claimed in  claim 27 , wherein the pitch of the windings of the tube around the tank is varied.  
     
     
         31 . The method as claimed in  claim 28 , wherein the pitch of the windings of the tube around the tank is varied.  
     
     
         32 . The method as claimed in  claim 29 , wherein the pitch of the windings of the tube around the tank is varied.  
     
     
         33 . The method as claimed in  claim 32 , wherein the spacing between adjacent windings is increased towards the top of the tank.