Heat Pump Water Heater

Abstract

A heat pump water heater includes a heat pump which generates a hot refrigerant and a water tank for water to be heated. The water tank includes a surrounding wall which is preferably cylindrical and a bottom portion. An inner sleeve is located in the bottom portion of the water tank, and is spaced from the bottom portion and an adjacent portion of the surrounding wall of the water tank, whereby a passageway is provided about the inner sleeve. The inner sleeve also includes an opening at a bottom thereof. A circulation system puts the heated refrigerant in a heat exchange relationship with the water in the passageway, causing heating of the water therein and, due to natural convection, movement of the heated water to a higher position in the water tank and a resultant flow of cooler water into the passageway through the bottom opening of the inner sleeve.

1 . A heat pump water heater comprising:
 a heat pump which supplies a hot refrigerant;   a water tank in which water to be heated is contained, said water tank including a lower portion defined by a bottom wall and a surrounding wall extending upwardly from said bottom wall;   an inner sleeve located in said lower portion of said water tank, said inner sleeve being spaced from said bottom wall and an adjacent portion of said surrounding wall whereby a passageway is provided about said inner sleeve, said inner sleeve also including an opening at a bottom thereof; and   a circulation system by which the heated refrigerant from said heat pump is put in a heat exchange relationship with the water in said passageway, causing heating of the water in said passageway and, due to natural convection, movement of the heated water to a higher position in said water tank and a resultant flow of cooler water into said passageway through said bottom opening of said inner sleeve.   
     
     
         2 . A heat pump water heater as claimed in  claim 1 , wherein said circulation system includes tubing which receives the hot refrigerant from said heat pump, said tubing being disposed on an outside surface of said water tank to heat the water in said passageway. 
     
     
         3 . A heat pump water heater as claimed in  claim 2 , wherein said water tank further includes grooves in the outside surface of the adjacent portion of said surrounding wall of said water tank in which said tubing is at least partially located. 
     
     
         4 . A heat pump water heater as claimed in  claim 3 , wherein said tubing is disposed in a spiral pattern in said grooves on the outside surface of the adjacent portion of said surrounding wall of said water tank. 
     
     
         5 . A heat pump water heater as claimed in  claim 2 , wherein said tubing includes an outer heat transfer promoting covering. 
     
     
         6 . A heat pump water heater as claimed in  claim 5 , wherein said tubing includes an outer protective covering. 
     
     
         7 . A heat pump water heater as claimed in  claim 1 , wherein said inner sleeve includes a spiral ridge thereabout. 
     
     
         8 . A heat pump water heater as claimed in  claim 1 , and further including:
 a water outlet pipe by which heated water is removed from said water tank; and   a water inlet pipe by which water to be heated is introduced into said water tank, said water inlet pipe including an outlet in said water tank which is inside of said inner sleeve and vertically adjacent to said bottom opening of said inner sleeve.   
     
     
         9 . A heat pump water heater as claimed in  claim 8 , wherein said outlet of said inlet pipe directs the introduced water downwards towards said bottom opening of said inner sleeve. 
     
     
         10 . A heat pump water heater as claimed in  claim 1 , wherein said bottom opening of said inner sleeve is flared downwardly and outwardly. 
     
     
         11 . A heat pump water heater as claimed in  claim 1 , wherein said bottom opening of said inner sleeve is flared downwardly and inwardly. 
     
     
         12 . A heat pump water heater as claimed in  claim 1 , wherein said bottom opening of said inner sleeve is flared straight downwardly. 
     
     
         13 . A heat pump water heater as claimed in  claim 1 , wherein said inner sleeve includes a spiral ridge on an inside surface thereof. 
     
     
         14 . A heat pump water heater comprising:
 a heat pump which supplies a hot refrigerant;   a cylindrical water tank in which water to be heated is contained, said water tank including a surrounding wall and a bottom wall and having a lower portion;   a cylindrical inner sleeve located in said lower portion of said cylindrical water tank, said inner sleeve being spaced from said bottom wall and an adjacent portion of said surrounding wall whereby a cylindrical passageway is provided about said inner sleeve, said inner sleeve also including an opening at a bottom thereof; and   a circulation system by which the heated refrigerant from said heat pump is circulated along the surrounding wall of said water tank and hence put in a heat exchange relationship with the water in said passageway, causing heating of the water in said passageway and, due to natural convection, movement of the heated water to a higher position in said water tank and a resultant flow of cooler water down through said inner sleeve and into said passageway through said bottom opening of said inner sleeve.   
     
     
         15 . A heat pump water heater as claimed in  claim 14 , wherein said circulation system includes tubing which receives the hot refrigerant from said heat pump, said tubing being disposed on an outside surface of said water tank to heat the water in said passageway. 
     
     
         16 . A heat pump water heater as claimed in  claim 15 , wherein said water tank further includes grooves in the outside surface of the adjacent portion of said surrounding wall of said water tank in which said tubing is located. 
     
     
         17 . A heat pump water heater as claimed in  claim 16 , wherein said tubing is disposed in a spiral pattern in said grooves on the outside surface of the adjacent portion of said surrounding wall of said water tank. 
     
     
         18 . A heat pump water heater as claimed in  claim 17 , wherein said inner sleeve includes a spiral ridge thereabout. 
     
     
         19 . A heat pump water heater as claimed in  claim 16 , and further including:
 a water outlet pipe by which heated water is removed from said water tank; and   a water inlet pipe by which water to be heated is introduced into said water tank, said water inlet pipe
 including an outlet in said water tank which is inside of said inner sleeve and vertically adjacent to said bottom opening of said inner sleeve. 
   
     
     
         20 . A heat pump water heater as claimed in  claim 19 , wherein said inner sleeve includes a spiral ridge on an inside surface thereof.