Ocean thermal energy conversion platform

• US 5,555,838 A
• Filed: 10/31/1994
• Issued: 09/17/1996
• Est. Priority Date: 10/31/1994
• Status: Expired due to Fees

• Current Assignee: Seatek International, Inc.
• Original Assignee: Seatek International, Inc.
• Inventors: Bergman, Gunnar B.
• Primary Examiner(s): AVILA, STEPHEN P
• Application Number:
  US08/329,489
• Time in Patent Office: 687 Days
• Field of Search: 114/125, 114/264, 114/265, 60/641.7
• US Class Current: 114/265
• CPC Class Codes: B63B 35/44 Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices construction methods for floating offshore platforms B63B75/00
• CPC Class Codes: F03G 7/05 Ocean thermal energy conversion, i.e. OTEC
• CPC Class Codes: Y02E 10/30 Energy from the sea, e.g. using wave energy or salinity gradient

Abstract

A method and apparatus for an OTEC platform are disclosed. The platform provides the high stability needed for OTEC applications. The platform includes a centrally located cold water pipe. The cold water pipe is suspended from a center column that is open at both the top and the bottom. The platform further includes multiple columns surrounding the cold water pipe. The columns extend from above the sea surface to deep depths below the sea surface. The OTEC platform also includes multiple power modules. The power modules are submersed below the sea surface and are utilized to provide stability to the platform. Moreover, the power modules are dispersed around the columns to provide additional stability. Various embodiments of the arrangement of the columns are also disclosed. The columns may be proximate the center column or may be placed an extended distance from the center column.

Claims

1. An ocean thermal energy conversion (OTEC) platform comprising:

a deck;

at least one buoyant column attached to said deck and extending below a sea surface;

at least one center column attached to said deck and extending below the sea surface, said center column being hollow and having an open top and an open bottom, said open top and open bottom permitting sea water to rise and fall within said center column;

a cold water pipe attached to said center column; and

at least one OTEC power module connected to said platform and submerged below the sea surface, said submerged power module acting as a pontoon to increase the stability of said platform.

2. The platform of claim 1 wherein said center column has a wall thickness no greater than needed for structural strength.

3. The platform of claim 1 wherein said center column and said cold water pipe are formed as a single center structure.

4. The platform of claim 1 further comprising cold water ducting attached to said center column for transporting cold water to said power modules.

5. The platform of claim 1 further comprising a plurality of buoyant columns wherein each of said at least one power module is connected to at least one of said plurality of buoyant columns.

6. The platform of claim 5 wherein one of said power modules is connected to each of said buoyant columns.

7. An ocean thermal energy conversion (OTEC) platform having a stability sufficient to be permanently stationed, comprising:

a center column, said center column extending from above a sea surface to below the sea surface, sea water allowed to rise and fall with said center column;

a plurality of buoyant columns attached to said center column and axisymmetrically dispersed about said center column, said buoyant columns extending from above the sea surface to below the sea surface;

a plurality of OTEC power modules attached to said buoyant columns, each of said power modules attached to at least one of said buoyant columns, said power modules being submerged below the sea surface and the lower ends of said power modules extending below said buoyant columns;

a cold water pipe suspended from said center column; and

a cold water passage comprising said cold water pipe and said center column, said cold water passage allowing cold water to be transported from deep ocean strata to said power modules.

8. The platform of claim 7 wherein said center column and cold water pipe are formed as a single structure.

9. The platform of claim 7 wherein said buoyant columns are placed proximate the center column.

10. The platform of claim 9 wherein said buoyant columns are an extended distance from said center column.

11. The platform of claim 10, said cold water passage further comprising cold water ducting connected between said center column and said buoyant columns.

12. The platform of claim 7 wherein said plurality of buoyant columns form an annular ring of buoyant columns about said center column.

13. The platform of claim 7 wherein said buoyant columns extend at least 60 meters or more below the sea surface.

14. The platform of claim 7 wherein said center column has an open top and an open bottom permitting sea water to rise and fall freely within said center column.

15. The platform of claim 14, further comprising a pump assembly located within said cold water passage, said pump assembly forcing cold water through said passage.

16. The platform of claim 7 wherein said power modules act as pontoons to provide stability to said platform.

17. An ocean thermal energy conversion (OTEC) platform comprising:

a deck;

a center column extending from said deck to below the sea surface, said center column being hollow and having an open top and an open bottom and permitting sea water to rise and fall within said center column;

a plurality of buoyancy columns attached to said center column and placed symmetrically about said center column, said buoyancy columns extending from said deck to below the sea surface;

a plurality of elongated members attached to said plurality of buoyancy columns, said elongated members being vertical and parallel to said buoyancy columns and fully submerged below the sea surface, a lower end of said elongated members extending below said buoyancy columns, together said elongated members providing a pontoon action to stabilize said platform.

18. The platform of claim 17 wherein said elongated members are power modules and at least two power modules are attached to each of said plurality of buoyancy columns.

19. A method of stabilizing an ocean thermal energy conversion (OTEC) platform, comprising the steps of:

providing a platform having a deck above a sea surface and a center structure;

placing a plurality of buoyancy columns around said center structure, said buoyancy columns attached to said center structure and extending from said deck to below the sea surface;

extending said center structure from said deck to deep ocean strata to access deep cold water;

permitting sea water to rise and fall freely within said center structure;

attaching a plurality of OTEC power modules to said plurality of buoyancy columns;

submerging said power modules under the sea surface such that a lower end of said modules extends to an ocean depth below said buoyancy columns; and

utilizing said submerged power modules to balance the wave forces acting on said platform.

20. The method of claim 19, further comprising:

forming said center structure from a center column and a cold water pipe, said center column having an open top.

21. A method of operating an ocean thermal energy conversion (OTEC) platform, comprising the steps of:

providing a platform having a deck, a center column, and a plurality of buoyancy columns dispersed about said center column, said center column extending above a sea surface;

allowing sea water to rise and fall freely within said center column;

attaching a plurality of OTEC power modules to said plurality of buoyancy columns;

submerging said power modules below the sea surface;

pumping cold water through a cold water pipe to said center column;

forcing said cold water from said center column through said plurality of buoyancy columns to said plurality of OTEC power modules.