WAVE POWERED GENERATION

• US 20070257491A1
• Filed: 03/09/2007
• Published: 11/08/2007
• Est. Priority Date: 05/05/2006
• Status: Active Grant

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Kornbluh, Roy D., Prahlad, Harsha, Pelrine, Ronald E., Stanford, Scott E., Low, Thomas, Chavez, Bryan, Eckerle, Joseph S., Chiba, Seiki
• Granted Patent: US 7,538,445 B2
• Time in Patent Office: Days
• US Class Current: 290/53
• CPC Class Codes: F03B 13/1845 and the wom slides relative to the rem
• CPC Class Codes: F03B 13/20 wherein both members , i.e. wom and rem are movable relative to the sea bed or shore
• CPC Class Codes: F05B 2250/44 one element moving inside another one, e.g. wave-operated member (wom) moving inside another member (rem)
• CPC Class Codes: F05B 2260/50 Kinematic linkage, i.e. transmission of position
• CPC Class Codes: Y02E 10/30 Energy from the sea, e.g. using wave energy or salinity gradient

Abstract

Described herein are marine devices and methods that convert mechanical energy in one or more waves to mechanical energy that is better suited for conversion into electrical energy. The marine devices employ a mechanical energy conversion system that harnesses wave energy and converts it into limited motion that is suitable for input to an electrical energy generator.

Claims

1. A marine device comprising:

a body, wherein the marine device is configured such that a portion of the body rests above a water surface level when the marine device floats;

a mechanical energy transmission system including a moving portion that is configured to move relative to the portion of the body that rests above the water surface level in response to a water surface level change; and

a generator mechanically coupled to the moving portion, mechanically coupled to the portion of the body that rests above the water surface level, and configured to produce electrical energy using movement of the moving portion.

2. The marine device of claim 1 wherein the body is configured such that the water surface level change causes movement of the body relative to the water surface level.

3. The marine device of claim 2 wherein the moving portion is configured to linearly translate relative to the portion of the body that rests above the surface level of water.

4. The marine device of claim 1 wherein the moving portion includes an energy storage mass that is configured to move relative to the body in response to the water surface level change.

5. The marine device of claim 4 wherein the energy storage mass is slideably coupled to a linear axis and the generator is configured to produce electrical energy using kinetic energy of the energy storage mass along the linear axis.

6. The marine device of claim 4 further comprising a spring mechanically coupled to the energy storage mass and mechanically coupled to the body.

7. The marine device of claim 6 wherein the mass is configured to displace in a direction substantially opposite to a direction of displacement for the body when the water surface level changes.

8. The marine device of claim 6 wherein the spring includes a tunable stiffness.

9. The marine device of claim 6 wherein the spring includes a stiffness that provides a resonant frequency for the mechanical energy transmission system within about 0.2 hertz of a resonant frequency for the marine device.

10. The marine device of claim 4 further comprising a second energy storage mass that is configured to move relative to the body in response to the water surface level change.

11. The marine device of claim 10 further comprising a second generator configured to produce electrical energy using kinetic energy of the second energy storage mass.

12. The marine device of claim 1 wherein the mechanical energy transmission system is configured to rest above the surface level of the water when the marine device floats in the water.

13. The marine device of claim 1 wherein the device is a navigation buoy and includes a light source configured to use electrical energy produced by the generator.

14. The marine device of claim 1 wherein the device is a floating electrical energy generation device and includes a tether configured to transport electrical energy from the floating generation device.

15. The marine device of claim 1 wherein the body includes a set of walls and an internal cavity and the mechanical energy transmission system and generator are disposed in the internal cavity.

16. A marine device comprising:

a body, wherein the marine device is configured such that a portion of the body rests above a surface level of water when the marine device floats;

a mechanical energy transmission system including

a) an energy storage mass that is configured to move relative to the body in response to a water surface level change, and

b) a spring mechanically coupled to the energy storage mass and mechanically coupled to the body,

wherein the spring includes a stiffness that provides a resonant frequency for the mechanical energy transmission system within about 0.2 hertz of a resonant frequency for the marine device body; and

a generator mechanically coupled to the energy storage mass and configured to produce electrical energy using kinetic energy of the energy storage mass.

17. The marine device of claim 16 wherein the energy storage mass is slideably coupled to a linear axis and the generator is configured to produce electrical energy using kinetic energy of the energy storage mass along the linear axis.

18. The marine device of claim 17 wherein the mass is configured to displace in a direction substantially opposite to a direction of displacement for the body when the water surface level changes.

19. The marine device of claim 16 further comprising a second energy storage mass that is configured to move relative to the body in response to the water surface level change.

20. A marine device comprising:

a body, wherein the marine device is configured such that a portion of the body rests above a surface level of water when the marine device floats;

a mechanical energy transmission system including

a) a first energy storage mass that is configured to move relative to the body in response to a water surface level change that causes tilting of the body relative to the water surface level, and

b) a second energy storage mass that is configured to move relative to the body in response to the water surface level change that causes tilting of the body relative to the water surface level;

a generator mechanically coupled to the energy storage mass and configured to produce electrical energy using kinetic energy of the energy storage mass.

21. The marine device of claim 20 wherein the energy storage mass is slideably coupled to a linear axis and the generator is configured to produce electrical energy using kinetic energy of the energy storage mass along the linear axis.

22. The marine device of claim 20 further comprising a spring mechanically coupled to the energy storage mass and mechanically coupled to the body.

23. The marine device of claim 20 wherein the first energy storage mass and the second first energy storage mass are configured to move at an angle relative to a vertical center of the body when the portion of the body rests above the water surface level.

24. A buoy comprising:

a body, wherein the buoy is configured such that a portion of the body rests above a surface level of water when the buoy floats;

a mechanical energy transmission system including a moving portion that is configured to move relative to the body in response to a water surface level change that causes movement of the body relative to the water surface level; and

a generator operably coupled to the moving portion and configured to produce electrical energy using movement of the moving portion; and

a light adapted to use electrical energy produced by the generator.

25. The buoy of claim 24 wherein the body includes a set of walls and an internal cavity and the mechanical energy transmission system and generator are disposed in the internal cavity.

26. The buoy of claim 24 wherein the internal cavity is configured to be added to the buoy after deployment of the buoy.

27. The buoy of claim 24 wherein the moving portion includes an energy storage mass that is slideably coupled to a linear axis and the generator is configured to produce electrical energy using kinetic energy of the energy storage mass along the linear axis.

28. The buoy of claim 27 further comprising a spring mechanically coupled to the energy storage mass and mechanically coupled to the body.

29. The buoy of claim 28 wherein the spring includes a tunable stiffness.

30. The buoy of claim 27 wherein the mechanical energy transmission system includes an energy storage mass that is configured to move at an angle relative to the water surface level.

31. A method of generating electrical energy in a marine device including a body and a mechanical energy transmission system, the method comprising:

floating the marine device such that a portion of the body rests above a water surface level when the marine device floats on the water;

moving a portion of the mechanical energy transmission system relative to the marine device body in response to a water surface level change; and

generating electrical energy using movement of the moving portion.

32. The method of claim 31 wherein the moving portion moves in a vertical direction in response to a rise in the water surface level.

33. The method of claim 31 the body rotates relative to a water surface level when the water surface level changes.

34. The method of claim 31, wherein the moving portion includes an energy storage mass, wherein the mechanical transmission system includes a spring coupled to the energy storage mass and coupled to the portion of the body, and further comprising compressing the spring in response to the water surface level change.

35. The method of claim 34 wherein the energy storage mass moves in a direction opposite to a direction of displacement for the body when the water surface level changes.

36. The method of claim 34 wherein the spring includes a tunable stiffness.

37. The method of claim 34 wherein the spring includes a stiffness that provides a resonant frequency for the energy storage mass and spring within about 0.2 hertz of a resonant frequency for the marine device.

38. The method of claim 34 wherein the mass is internal to a cavity in the body.

39. The method of claim 31 wherein the moving portion includes a rod that mechanically couples to a water brake that rests below the water surface level.