Heat pump water heater

1. A heat pump water heater comprising:

a water storage tank;

an outer jacket surrounding the water storage tank; and

a heat exchange circuit comprising a heat absorber positioned below said water storage tank and a heat transfer region in fluid communication with said heat absorber and positioned within said water storage tank to be immersed in water contained within said water storage tank, said heat absorber being configured to transfer heat to fluid in said heat exchange circuit, and said heat transfer region being configured to transfer heat from fluid in said heat exchange circuit to water in said water storage tank;

wherein said heat pump water heater defines an air supply passage upstream of said heat absorber; and

wherein said air supply passage extends through an interior of said water storage tank and is positioned to be immersed in water contained within said water storage tank.

2. The heat pump water heater of claim 1 , wherein said water storage tank is vertically oriented.

3. The heat pump water heater of claim 1 , wherein said heat absorber has an arcuate profile.

4. The heat pump water heater of claim 3 , wherein said arcuate profile of said heat absorber is semicircular.

5. The heat pump water heater of claim 1 , wherein said heat exchange circuit further comprises a compressor configured to pressurize fluid in said heat exchange circuit.

6. The heat pump water heater of claim 5 , wherein said compressor is positioned below said water storage tank.

7. The heat pump water heater of claim 1 , wherein said heat transfer region comprises at least one coil.

8. The heat pump water heater of claim 1 , wherein said heat exchange circuit further comprises an expansion valve configured to depressurize fluid in said heat exchange circuit.

9. The heat pump water heater of claim 1 , wherein said air supply passage has an inlet positioned above said heat absorber.

10. The heat pump water heater of claim 9 further comprising a filter positioned to filter particulate matter from the air in said air supply passage.

11. The heat pump water heater of claim 1 , wherein said heat transfer region comprises at least one coil disposed around said air supply passage.

12. The heat pump water heater of claim 1 , wherein said heat pump water heater defines an air discharge passage downstream of said heat absorber.

13. The heat pump water heater of claim 12 , wherein said air discharge passage has an outlet positioned above said heat absorber of said heat pump water heater.

14. A heat pump water heater comprising:

a water storage tank positioned in an upper portion of said heat pump water heater;

an outer jacket surrounding the water storage tank; and

a heat exchange circuit comprising a heat absorber positioned in a lower portion of said heat pump water heater below said water storage tank and a heat transfer region in fluid communication with said heat absorber and positioned within said water storage tank to be immersed in water contained within said water storage tank;

said heat absorber being configured to transfer heat to fluid in said heat exchange circuit, and said heat transfer region being configured to transfer heat from fluid in said heat exchange circuit to water in said water storage tank;

wherein said heat pump water heater defines an air supply passage upstream of said heat absorber and having an inlet positioned above said lower portion of said heat pump water heater; and

wherein said air supply passage extends through an interior of said water storage tank and is positioned to be immersed in water contained within said water storage tank.

15. A method of manufacturing a heat pump water heater comprising the steps of:

positioning a water storage tank within an upper portion of a jacket of the heat pump water heater;

positioning a heat absorber in a lower portion of the jacket below the water storage tank;

positioning an air supply passage upstream of the heat absorber and through an interior of said water storage tank, such that, in operation, the air supply passage is positioned to be immersed in water contained within the water storage tank, wherein the air supply passage is positioned to deliver supply air to the heat absorber;

positioning a heat transfer region within the water storage tank, such that, in operation, the heat transfer region is positioned to be immersed in water contained within the water storage tank; and

coupling the heat absorber and heat transfer region to form a heat exchange circuit, wherein the heat absorber is configured to transfer heat to fluid in the heat exchange circuit, and the heat transfer region is configured to transfer heat from fluid in the heat exchange circuit to water in the water storage tank.

16. A heat pump water heater comprising:

a water storage tank;

an outer jacket surrounding the water storage tank; and

a heat exchange circuit comprising a heat absorber, a compressor positioned below said water storage tank and being configured to pressurize fluid in said heat exchange circuit, and a heat transfer region in fluid communication with said heat absorber and positioned within said water storage tank to be immersed in water contained within said water storage tank, said heat absorber being configured to transfer heat to fluid in said heat exchange circuit, and said heat transfer region being configured to transfer heat from fluid in said heat exchange circuit to water in said water storage tank;

wherein said heat pump water heater defines an air supply passage upstream of said heat absorber; and

wherein said air supply passage extends through an interior of said water storage tank and is positioned to be immersed in water contained within said water storage tank.