METHOD AND SYSTEM FOR EXTRACTING KINETIC ENERGY FROM SURFACE WAVES OF A WATER

• US 20160237980A1
• Filed: 10/10/2013
• Published: 08/18/2016
• Est. Priority Date: 10/10/2013
• Status: Active Grant

• Current Assignee: Rijksuniversiteit Groningen
• Original Assignee: Rijksuniversiteit Groningen
• Inventors: PRINS, WOUTER ADRIANUS
• Granted Patent: US 9,951,747 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F03B 13/187 and the wom directly actuates the piston of a pump
• 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: F03B 15/02 by varying liquid flow
• CPC Class Codes: F05B 2270/20 to optimise the performance of a machine
• CPC Class Codes: F05B 2270/202 Tuning to wave conditions
• CPC Class Codes: F05B 2270/30 Control parameters, e.g. input parameters
• CPC Class Codes: Y02E 10/30 Energy from the sea, e.g. using wave energy or salinity gradient

Abstract

The invention relates to extracting kinetic energy from surface waves. Therein, at least one float (8) is kept floating in the area of the surface waves, while a working fluid is held in a reservoir structure (2, 3). The float is connected to a fluid displacement structure in such manner that an individual surface wave, which causes an upward stroke of the float, moves the working fluid within the reservoir structure in such manner that the potential energy of the working fluid is increased. Before the wave has reached the float, the wave is detected by a sensor (7). Based on said detection, a prediction is calculated of the amount of kinetic energy available in the wave. Tuned to said prediction, an energy transmission structure of the fluid displacement structure is adjusted for realizing the energy conversion.

Claims

1. A method for extracting kinetic energy from surface waves of a water, said waves moving in a horizontal wave movement direction along the water surface of the water, wherein:

at least one float is kept floating in the area of the surface waves, with partly restricted freedom of floating movements of the float, such that the float is moved by the surface waves at least in reciprocating upward and downward strokes of the float;

a working fluid is held in a reservoir structure;

the float is connected to a fluid displacement structure in such manner that for at least one individual surface wave of said surface waves the corresponding upward stroke of the float, which corresponding upward stroke is caused by said individual surface wave having reached the float, moves, via the fluid displacement structure, the working fluid within the reservoir structure in such manner that the potential energy of the working fluid increases, whereby, accordingly, via the float and via the fluid displacement structure, kinetic energy is extracted from said individual surface wave and converted into increased potential energy of the working fluid;

with the aid of at least one sensor said individual surface wave is detected before said individual surface wave has reached the float;

with the aid of at least one calculator, and based on said detection, there is calculated a prediction being indicative of the amount of kinetic energy available in said individual surface wave for realizing said conversion into increased potential energy of the working fluid during said corresponding upward stroke of the float; and

with the aid of at least one controller, and tuned to said calculated prediction being indicative of the amount of the kinetic energy available in said individual surface wave, an energy transmission structure of the fluid displacement structure is adjusted for realizing said conversion into increased potential energy of the working fluid during said corresponding upward stroke of the float.

2. A method according to claim 1, wherein said adjusting of said energy transmission structure of said fluid displacement structure for realizing said conversion into increased potential energy of the working fluid during said corresponding upward stroke of the float at least partly takes place during a previous downward stroke of the float, which previous downward stroke, in the sense of said reciprocating upward and downward strokes of the float, directly precedes said corresponding upward stroke of the float.

3. A method according to claim 1, wherein said adjusting of said energy transmission structure of said fluid displacement structure comprises adjustment of a contact surface configuration of said energy transmission structure, which contact surface configuration contactingly acts upon the working fluid in the reservoir structure.

4. A method according to claim 1, wherein said adjusting of said energy transmission structure of said fluid displacement structure comprises gear adjustment of a gear structure of said energy transmission structure.

5. A method according to claim 1, wherein:

the at least one float comprises at least one further such a float, said further float having its own corresponding further such reciprocating upward and downward strokes and being connected in the said manner to a further such fluid displacement structure having a further such energy transmission structure, wherein the float together with said at least one further float are situated downstream of one another in a float-after-float fashion, thus forming a float-after-float assembly, wherein the term “

downstream”

is interpreted in the sense of said horizontal wave movement direction of said individual surface wave;

with the aid of said at least one sensor said individual surface wave is detected before said individual surface wave has reached said further float;

with the aid of said at least one calculator, and based on said detection before said individual surface wave has reached said further float, there is calculated a further prediction being indicative of the amount of kinetic energy available in said individual surface wave for realizing said conversion into increased potential energy of the working fluid during said corresponding further upward stroke of the further float; and

with the aid of said at least one controller, and tuned to said calculated further prediction being indicative of the amount of the kinetic energy available in said individual surface wave, said further energy transmission structure of said further fluid displacement structure is adjusted for realizing said conversion into increased potential energy of the working fluid during said corresponding further upward stroke of the further float.

6. A method according to claim 5, wherein downstreamly adjoining floats of said float-after-float assembly are hingeably interconnected.

7. A method according to claim 1, wherein:

the working fluid is a working liquid;

the reservoir structure comprises an upper reservoir, a lower reservoir and a first liquid guiding structure, the upper reservoir being located in the water at least partly below the water surface of the water and at least partly below the at least one float, the lower reservoir being located in the water at least partly below the water surface of the water and at least partly below the upper reservoir, and the first liquid guiding structure interconnecting the upper reservoir and the lower reservoir; and

the fluid displacement structure comprises a hoist structure and a one-way valve structure;

and wherein the method further comprises;

moving at least part of the working liquid successively out of the lower reservoir, through the first liquid guiding structure, and into the upper reservoir during said corresponding upward stroke of the float, said moving being performed against the action of gravity and under the action of said hoist structure being actuated by the float performing said corresponding upward stroke; and

preventing that during a next corresponding downward stroke of the float, which next corresponding downward stroke of the float, in the sense of said reciprocating upward and downward strokes of the float, directly follows said corresponding upward stroke of the float, at least part of the working liquid under the action of gravity flows back from the upper reservoir, through the first liquid guiding structure, and into the lower reservoir, said preventing being provided by a condition of said one-way valve structure.

8. A method according to claim 7, wherein:

the reservoir structure comprises a second liquid guiding structure, which interconnects the upper reservoir and the lower reservoir;

and wherein the method further comprises;

allowing the working liquid to successively flow, under the action of gravity, out of the upper reservoir, through the second liquid guiding structure, and into the lower reservoir, while generating electrical energy from said flow via at least one turbine.

9. A system for extracting kinetic energy from surface waves of a water, said waves moving in a horizontal wave movement direction along the water surface of the water, the system comprising:

at least one float, which is kept floating in the area of the surface waves, with partly restricted freedom of floating movements of the float, such that the float is moved by the surface waves at least in reciprocating upward and downward strokes of the float;

a reservoir structure for holding a working fluid therein;

a fluid displacement structure, which comprises an energy transmission structure and which is connected to the float in such manner that for at least one individual surface wave of said surface waves the corresponding upward stroke of the float, which corresponding upward stroke is caused by said individual surface wave having reached the float, moves, via the fluid displacement structure, the working fluid within the reservoir structure in such manner that the potential energy of the working fluid increases, whereby, accordingly, via the float and via the fluid displacement structure, kinetic energy is extracted from said individual surface wave and, via said energy transmission structure, converted into increased potential energy of the working fluid;

at least one sensor, configured, arranged and effective to detect said individual surface wave before said individual surface wave has reached the float;

at least one calculator, which is communicatively connected to said at least one sensor and which is configured, arranged and effective to calculate, based on said detection, a prediction being indicative of the amount of kinetic energy available in said individual surface wave for realizing said conversion into increased potential energy of the working fluid during said corresponding upward stroke of the float; and

at least one controller, which is communicatively connected to said at least one calculator and which is configured, arranged and effective to adjust, in a manner tuned to said calculated prediction being indicative of the amount of the kinetic energy available in said individual surface wave, said energy transmission structure for realizing said conversion into increased potential energy of the working fluid during said corresponding upward stroke of the float.

10. A system according to claim 9, wherein said at least one controller is configured, arranged and effective to perform said adjusting of said energy transmission structure of said fluid displacement structure, for realizing said conversion into increased potential energy of the working fluid during said corresponding upward stroke of the float, at least partly during a previous downward stroke of the float, which previous downward stroke, in the sense of said reciprocating upward and downward strokes of the float, directly precedes said corresponding upward stroke of the float.

11. A system according to claim 9, wherein said adjusting of said energy transmission structure of said fluid displacement structure comprises adjustment of a contact surface configuration of said energy transmission structure, which contact surface configuration contactingly acts upon the working fluid in the reservoir structure.

12. A system according to claim 9, wherein said adjusting of said energy transmission structure of said fluid displacement structure comprises gear adjustment of a gear structure of said energy transmission structure.

13. A system according to claim 9, wherein:

the at least one float comprises at least one further such a float, said further float having its own corresponding further such reciprocating upward and downward strokes and being connected in the said manner to a further such fluid displacement structure having a further such energy transmission structure, wherein the float together with said at least one further float are situated downstream of one another in a float-after-float fashion, thus forming a float-after-float assembly, wherein the term “

downstream”

is interpreted in the sense of said horizontal wave movement direction of said individual surface wave;

said at least one sensor is configured, arranged and effective to detect said individual surface wave before said individual surface wave has reached said further float;

said at least one calculator is configured, arranged and effective to calculate, based on said detection before said individual surface wave has reached said further float, a further prediction being indicative of the amount of kinetic energy available in said individual surface wave for realizing said conversion into increased potential energy of the working fluid during said corresponding further upward stroke of the further float; and

said at least one controller is configured, arranged and effective to adjust, in a manner tuned to said calculated further prediction being indicative of the amount of the kinetic energy available in said individual surface wave, said further energy transmission structure of said further fluid displacement structure for realizing said conversion into increased potential energy of the working fluid during said corresponding further upward stroke of the further float.

14. A system according to claim 13, wherein downstreamly adjoining floats of said float-after-float assembly are hingeably interconnected.

15. A system according to claim 9, wherein:

the reservoir structure comprises an upper reservoir, a lower reservoir and a first liquid guiding structure, the upper reservoir being located in the water at least partly below the water surface of the water and at least partly below the at least one float, the lower reservoir being located in the water at least partly below the water surface of the water and at least partly below the upper reservoir, and the first liquid guiding structure interconnecting the upper reservoir and the lower reservoir;

the fluid displacement structure comprises a hoist structure and a one-way valve structure;

the fluid displacement structure is configured, arranged and effective to move, when the working fluid is a working liquid held in the reservoir structure, at least part of the working liquid successively out of the lower reservoir, through the first liquid guiding structure, and into the upper reservoir during said corresponding upward stroke of the float, said moving being performed against the action of gravity and under the action of said hoist structure being actuated by the float performing said corresponding upward stroke; and

the fluid displacement structure is configured, arranged and effective to prevent, when the working fluid is a working liquid held in the reservoir structure, that during a next corresponding downward stroke of the float, which next corresponding downward stroke of the float, in the sense of said reciprocating upward and downward strokes of the float, directly follows said corresponding upward stroke of the float, at least part of the working liquid under the action of gravity flows back from the upper reservoir, through the first liquid guiding structure, and into the lower reservoir, said preventing being provided by a condition of said one-way valve structure.

16. A system according to claim 15, wherein the reservoir structure comprises a second liquid guiding structure, which interconnects the upper reservoir and the lower reservoir, and which allows the working liquid to successively flow, under the action of gravity, out of the upper reservoir, through the second liquid guiding structure, and into the lower reservoir, while generating electrical energy from said flow via at least one turbine.