Heat pump water heater

Patent metadata

Field	Value
Publication number	US-10429084-B2
Application number	US-201715438350-A
Country	US
Kind code	B2
Filing date	Feb 21, 2017
Priority date	Feb 21, 2017
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

A water heater includes a water tank for storing water to be heated and a thermosiphon tube in the water tank. The thermosiphon tube has a first end in a bottom portion of the water tank and a second end in a top portion of the water tank. At least a portion of a condenser tube of a heat pump is surrounded by the thermosiphon tube to define a water flow channel between the thermosiphon tube and the condenser tube. The condenser tube is at an elevated temperature compared to water temperature in the water flow channel due to a refrigerant cycle of the heat pump. A water pump is configured to flow water through the water flow channel to heat the water in the water flow channel and deliver the heated water into the top portion of the water tank through the second end of the thermosiphon tube.

First claim

What is claimed is:

1. A water heater comprising:
a water tank for storing water to be heated, the water tank including a thermosiphon inlet port and a pump inlet port;
a thermosiphon tube in the water tank and having a first end in a bottom portion of the water tank communicating with the thermosiphon inlet port such that all water flowing through the thermosiphon inlet port flows into the thermosiphon tube and a second end in a top portion of the water tank;
a heat pump system including an evaporator, a compressor, an expansion device, and a condenser tube for moving a refrigerant through a refrigerant cycle, at least a portion of the condenser tube being surrounded by the thermosiphon tube to define a water flow channel between the thermosiphon tube and the condenser tube, the water flow channel having a first end at the first end of the thermosiphon tube and a second end at the second end of the thermosiphon tube, the condenser tube being at an elevated temperature compared to water temperature in the water flow channel due to the refrigerant cycle; and
a water pump configured to draw water from the water tank through the pump inlet port and generate forced water flow through the thermosiphon inlet port such that the entire forced water flow flows through the water flow channel to heat the water in the water flow channel and deliver the heated water into the top portion of the water tank through the second end of the thermosiphon tube.

2. The water heater of claim 1 , wherein the thermosiphon tube defines high and low openings communicating between the water flow channel and the top portion of the water tank, wherein each of the high and low openings communicates the channel with the water tank, the low opening being positioned below the high opening.

3. The water heater of claim 2 , wherein the thermosiphon tube defines a intermediate opening communicating between the water flow channel and the top portion of the water tank, the intermediate opening being positioned between the high and low openings.

4. The water heater of claim 1 , wherein the water pump communicates between the bottom portion of the water tank and the water flow channel to provide water to the water flow channel when a temperature of water in the water tank drops below a set point.

5. The water heater of claim 4 , wherein the water pump flows water outside of the tank before pumping water into the water flow channel.

6. The water heater of claim 1 ,
wherein the thermosiphon tube includes a coil section positioned within the bottom portion of the water tank.

7. The water heater of claim 6 , wherein the thermosiphon tube includes a straight section extending upward from the coil section to the second end within the top portion of the water tank.

8. The water heater of claim 1 , further comprising an electric heating element extending into the water tank.

9. The water heater of claim 1 , wherein the refrigerant moves through the condenser tube in an opposite direction to the water flowing through the water flow channel.

10. The water heater of claim 1 , wherein the water pump is controllable to vary flow rate of water through the water flow channel.

11. The water heater of claim 1 , wherein pressure within the water flow channel and pressure within the tank are substantially equivalent.

12. The water heater of claim 1 , wherein the thermosiphon tube is made of a thin-walled plastic material.

13. A method of heating water comprising:
providing a water tank for storing water to be heated, the water tank including a thermosiphon inlet port and a pump inlet port, a thermosiphon tube in the water tank having a first end in a bottom portion of the water tank communicating with the thermosiphon inlet port such that all water flowing through the thermosiphon inlet port flows into the thermosiphon tube and a second end in a top portion of the water tank, and a condenser tube in the water tank, at least a portion of the condenser tube surrounded by the thermosiphon tube to define a water flow channel between the thermosiphon tube and the condenser tube, the water flow channel having a first end at the first end of the thermosiphon tube and a second end at the second end of the thermosiphon tube;
moving a refrigerant through a refrigeration cycle including through the condenser tube, the condenser tube being at an elevated temperature compared to water temperature in the water flow channel due to the refrigerant cycle;
flowing water, by a water pump, through the water flow channel,
wherein flowing water includes drawing water from the water tank through the pump inlet port by the water pump and generating forced water flow through the thermosiphon inlet port such that the entire forced water flow flows through the water flow channel;
heating water within the water flow channel via an exchange of heat from the condenser tube; and
delivering the heated water from the water flow channel into the top portion of the water tank through the second end of the thermosiphon tube.

14. The method of claim 13 , wherein the heated water is delivered to a corresponding volume within the water tank based on a temperature of the heated water, the volume being one of a plurality of volumes distributed based on thermal stratification of water within the water tank.

15. The method of claim 14 , wherein the thermosiphon tube defines a plurality of openings, wherein each of the openings corresponds to one of the plurality of volumes to communicate the water flow channel with each of the volumes, and wherein the heated water enters the volume via a corresponding one of the openings.

16. The method of claim 14 , wherein the temperature of the heated water is equal to or greater than a temperature of water within the volume to which the heated water is delivered.

17. The method of claim 13 , further comprising flowing water from the bottom portion of the water tank into the water flow channel to provide water to the water flow channel when a temperature of water in the water tank drops below a set point and water is not being drawn from the water tank.

18. The method of claim 13 , wherein flowing water through the water flow channel includes flowing the water through a coil section of the thermosiphon tube within the bottom portion of the water tank.

19. The method of claim 18 , wherein flowing water through the water flow channel includes flowing the water through a straight section of the thermosiphon tube extending from the coil section toward the second end.

20. The method of claim 13 , further comprising heating water within the water tank with an electric heating element if a temperature of the water within the water tank drops below a set point.

21. The method of claim 13 , wherein the refrigerant moves through the condenser tube in an opposite direction to the water flowing through the water flow channel.

Assignees

• Smith Corp A O

Inventors

• Yin Jianmin

Classifications

• Y02B10/20

  Solar thermal · CPC title

• F24D2200/123

  Compression type heat pumps · CPC title

• F24D17/02

  using heat pumps · CPC title

• F28D2020/0069

  Distributing arrangements; Fluid deflecting means · CPC title

• F28D20/0039

  with stratification of the heat storage material · CPC title