SINGLE BI-TEMPERATURE THERMAL STORAGE TANK FOR APPLICATION IN SOLAR THERMAL PLANT

• US 20100301062A1
• Filed: 12/16/2009
• Published: 12/02/2010
• Est. Priority Date: 06/01/2009
• Status: Active Grant

• Current Assignee: SolarReserve Technology, LLC
• Original Assignee: SolarReserve Technology, LLC
• Inventors: Wait, David, Litwin, Robert Zachary, Lancet, Robert T.
• Granted Patent: US 9,657,966 B2
• Time in Patent Office: Days
• US Class Current: 220/734
• CPC Class Codes: F24S 60/10 using latent heat
• CPC Class Codes: F24S 60/30 storing heat in liquids
• CPC Class Codes: F28D 20/0039 with stratification of the heat storage material
• CPC Class Codes: F28D 2020/0047 using molten salts or liquid metals
• CPC Class Codes: F28D 2020/0091 flexible
• CPC Class Codes: F28F 2265/14 for preventing damage by freezing, e.g. for accommodating volume expansion
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y02E 60/14 Thermal energy storage
• CPC Class Codes: Y02E 70/30 Systems combining energy storage with energy generation of non-fossil origin

Abstract

Thermocline storage tanks for solar power systems are disclosed. A thermocline region is provided between hot and cold storage regions of a fluid within the storage tank cavity. One example storage tank includes spaced apart baffles fixed relative to the tank and arranged within the thermocline region to substantially physically separate the cavity into hot and cold storage regions. In another example, a flexible baffle separated the hot and cold storage regions and deflects as the thermocline region shifts to accommodate changing hot and cold volumes. In yet another example, a controller is configured to move a baffle within the thermocline region in response to flow rates from hot and cold pumps, which are used to pump the fluid.

Claims

1. A storage tank for a solar power system comprising:

a structure including an outer wall adjoining a bottom wall and providing a cavity configured to store a fluid; and

multiple baffles arranged in the cavity and spaced from the bottom wall in a thermocline region, the baffles including a perimeter arranged in close proximity to and fixed relative to the outer wall, the baffles configured to substantially physically separate the cavity into hot and cold storage regions.

2. The storage tank according to claim 1, wherein the baffles are spaced vertically from one another within the thermocline region.

3. The storage tank according to claim 2, wherein the baffles include multiple perforations arranged inboard of the perimeter and configured to permit substantially limited flow between the hot and cold storage regions through the baffles.

4. The storage tank according to claim 3, wherein a first set of perforations in a first baffle are offset from a second set of perforations on a second baffle.

5. The storage tank according to claim 2, wherein the cavity includes a tank height, the baffles arranged vertically within the thermocline region over a distance greater than 5% of the tank height.

6. The storage tank according to claim 1, comprising at least one generally vertical support post arranged inboard of the outer wall operatively connected to at least one baffle.

7. A storage tank for a solar power system comprising:

a structure including an outer wall adjoining a bottom wall and providing a tank cavity configured to store a fluid; and

a flexible baffle arranged in the cavity and spaced from the bottom wall, the flexible baffle including a perimeter substantially sealed and affixed to the outer wall and configured to substantially physically separate the cavity into hot and cold cavities at a thermocline region, the flexible baffle configured to deflect within the thermocline region in response to varying hot and cold volumes respectively provided by the hot and cold cavities as the thermocline region shifts.

8. The storage tank according to claim 7, wherein the flexible baffle includes corrugations configured to deflect permitting a change in hot and cold volumes.

9. The storage tank according to claim 7, wherein the flexible baffle includes at least one aperture and comprising an element extending between the hot and cold cavities through the aperture, the aperture providing a flow area between the element and the flexible baffle configured to permit fluid flow between the hot and cold cavities, the flow area corresponding to less than 1% of a horizontal cross-section through the tank cavity at the thermocline region.

10. The storage tank according to claim 9, wherein the element is a pumping conduit in fluid communication with the cold cavity.

11. The storage tank according to claim 7, comprising hot and cold pumps respectively in fluid communication with the hot and cold cavities, the flexible membrane configured to expand in the vertical direction to accommodate about 95% of either of the hot and cold cavities in response to pumping fluid thereto and therefrom.

12. A storage tank for a solar power system comprising:

a structure including an outer wall adjoining a bottom wall and providing a cavity configured to store a fluid;

a movable baffle arranged in the cavity and spaced from the bottom wall in a thermocline region, the baffle including a perimeter arranged in close proximity to the outer wall and configured to substantially physically separate the cavity into hot and cold storage regions;

hot and cold pumps respectively in fluid communication with the hot and cold regions configured to pump fluid at flow rates to and from the hot and cold storage regions thereby shifting the thermocline region; and

a controller in communication with at least one of the hot and cold pumps and configured to move the baffle within the shifting thermocline region based upon at least one of the flow rates.

13. The storage tank according to claim 12, wherein the flexible baffle includes at least one aperture and comprising an element extending between the hot and cold storage regions through the aperture.

14. The storage tank according to claim 13, wherein the element is pumping conduit in fluid communication with at least one of the pumps.

15. The storage tank according to claim 13, wherein the element is a generally vertical support post arranged inboard of the outer wall.

16. A tank comprising:

a wall having a portion;

a baffle located in a thermal gradient region; and

a skirt attached to the baffle, the skirt having a geometry based at least in part on the portion, the skirt proximate to the portion.

17. The tank of claim 16, wherein the portion defines at least a majority of a vertical portion of the wall.

18. The tank of claim 16, wherein the baffle substantially separates a first volume and second volume.

19. The tank of claim 18, wherein a hot fluid is in the first volume and a cold fluid is in the second volume.

20. The tank of claim 19, wherein a mixing of the hot fluid and the cold fluid is limited by the baffle.

21. The tank of claim 20, wherein the baffle includes plural openings.

22. The tank of claim 21, wherein the plural openings permit substantially limited flow between the first volume and the second volume.

23. A tank comprising:

a wall having a portion;

a membrane located in a thermal gradient region; and

a skirt attached to the membrane, the skirt having a geometry based at least in part on the portion, the skirt proximate to the portion.

24. The tank of claim 23, wherein the portion is a vertical portion.

25. The tank of claim 23, wherein the membrane substantially separates a first volume and second volume.

26. The tank of claim 25, wherein a hot fluid is in the first volume and a cold fluid is in the second volume.

27. The tank of claim 26, wherein a mixing of the hot fluid and the cold fluid is limited by the membrane.

28. The tank of claim 27, wherein the membrane includes plural openings.

29. The tank of claim 28, wherein the plural openings permit substantially limited flow between the first volume and the second volume.