WO2001073289A1

WO2001073289A1 - Device for utilisation of wave energy

Info

Publication number: WO2001073289A1
Application number: PCT/NO2001/000117
Authority: WO
Inventors: Arvid Nesheim
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-03-24
Filing date: 2001-03-20
Publication date: 2001-10-04
Anticipated expiration: 2002-09-24
Also published as: NO20001537D0; NO20001537L; AU2001242895A1; NO311371B1

Abstract

Device for the conversion of wave energy into useful energy, which includes a float (1) placed around a vertical column (2), a coupling (comprising 4, 5, 6, 7 and 8) and energy converters (9, 10, 11). By means of the coupling (4, 5, 6, 7, 8) the float (1) is arranged for both axial movement and pivotal movement in relation to the vertical column (2). Energy converters (9, 10) are placed in connection with the coupling's (4, 5, 6, 7, 8) pivotal movement, and energy converters (11) are placed in connection with the bearing unit's (4) axial movement so that the energy in both the float's (1) upwards/downwards movement and pivotal movement about horizontal axes are utilised. The energy in the waves is thus transformed into useful energy, eg electrical energy.

Description

DEVICE FOR UTILISATION OF WAVE ENERGY

The invention in question relates to a device for the extraction of energy from wave motion, primarily ocean or sea waves, as well as conversion of the extracted energy into useful energy. The extracted energy from the waves can be converted into useful energy by means of many different types of converters such as electrical generators, water pumps, hydraulic pumps or other equipment.

Other devices for the conversion of wave energy into useful energy are known. Reference is made to the following publications:

GB 2261262 showing a toroidally-shaped float, pivotally mounted to the top of a vertical column. Wave movement causes pivotal movement of the float about the horizontal axes. The float's pivotal movement in relation to the column is via a transmission system transferred to a generator placed inside the column. The device utilises only relative pivotal movement between the float and the column. The transmission system consists of a relatively large number of parts. The mooring of the device is relatively complicated.

US 5986349 shows a toroidally-shaped float placed around a vertical column. The toroidally-shaped float consists of four segments hinged to the column. The segments can move independently of each other. The motion of ocean waves causes the segments to move upwards and downwards. The movement of the float segments in relation to the column is utilised to drive energy converters. The mooring of the device is relatively complicated.

US 4352023 shows a gyroscope mechanism mounted on a float. In response to wave motion, the float will turn or pivot about horizontal axes. The gyroscope mechanism converts the pivotal motion of the float into rotational movement to drive electrical generators. The device does not utilise the relative movement of two partly submerged bodies.

The Kepler Buoy published on the Internet. The device consists of a round float slidably mounted at the top of a vertical column and a round plate rigidly mounted to the lower end. In response to wave motion, the float will move upwards and downwards whilst the column is prevented from moving by the plate due to drag resistance in the water. The float's motion in relation to the column is utilised to generate useful energy. The device utilises only the float's upwards and downwards movement. The invention in question concerns a float (1) placed around a vertical column (2), a coupling (comprising 4, 5, 6, 7 and 8) and energy converters (9, 10, 11) being activated by the float's (1) motion in relation to the column (2). The vertical column's (2) lower part is placed below the water surface and the upper part extends above the water surface through the float (1) and is coupled to the float by means of the coupling (4, 5, 6, 7, 8).

The special features of the invention in question, compared to existing technology, is that the float (1) is arranged for both axial movement and pivotal movement in relation to the vertical column (2) so that the energy in both forms of motion can be utilised.

In addition, the device utilises horizontal backwards and forwards (to-and-fro) movement, which causes pivotal movement of the float (1) in relation to the vertical column (2). Horizontal to-and-fro movement will occur when the device is moored to a buoy, or other device, which could act as a spring.

Another aspect that increases energy extraction from the waves is the design of the float (1). The float (1) has a relatively large volume compared to its own mass and will thereby easily move in response to the ocean waves. Furthermore, the float's cross-section, shown on section B-B figure 7, is shaped so that the lower part (lc) is relatively narrow or pointed to reduce the hydrodynamic resistance in the water when the float oscillates.

A further aspect which increases energy extraction is the vertical column (2) being arranged so that it will move relatively little in response to the waves. This is achieved primarily by the volume of the column being relatively little and narrow near the water surface where the water-particle velocity is high. Secondly, the column (2) is equipped with a chamber (3) which partially or completely encloses a mass of water. If acceleration and movement of the vertical column is to occur, the water inside the chamber (3) and some of the water outside the chamber will have to follow the movement. In order to accelerate this mass (hydrodynamic mass) an inertia force is required. In addition, movement of the vertical columns (2) and chamber (3) will be resisted by hydrodynamic dampening forces or drag forces. Inertia and drag forces will thereby counteract movement of the vertical column (2). The chamber (3) will be affected relatively little by wave forces since it is situated some distance below the water surface where the water particle velocity is relatively low.

Another aim of the invention in question is to provide a device comprising relatively few parts and which is easy and inexpensive to manufacture. A further aim of the invention in question is to provide a device that is easy to deploy and operate. The equipment for energy conversion is easily accessed for inspection and repairs. The device can easily be moored by use of one or more lines/cables connected to buoys or to fastening points on shore.

To provide a clearer understanding of the invention in question, reference is made to the following descriptions and drawings.

Fig. 1 showing an isometric view of the device

Fig. 2 showing a side view of the device Fig. 3 showing view A-A from fig. 2

Fig. 4 showing a top plan view of the device

Fig. 5 showing an example of mooring of the device

Fig. 6 showing alternative example of mooring of the device

Fig. 7 showing section B-B from fig. 4 Fig. 8 showing a top plan view of the float (1) and the coupling (comprising 4,

5, 6, 7 and 8)

The drawings are intended solely as illustrations to describe the principles of the invention in question. Therefore not all the required detail has necessarily been shown. Furthermore, the size of the items and components in relation to each other are not necessarily to scale. We would also mention that identical reference numbers are used for the elements and components in all the drawings. We would point out that the figures show one design example only. The design may be changed in many ways, eg the elements may be constructed with different cross sections and contours. We would also mention that the number and location of the energy converters (9, 10, 11) may differ from those shown. The elements and components can be made from many different types of material such as composites, plastics, metals etc.

The float (1) may for example be a shell structure reinforced with plate stiffeners or a solid body made from a low weight material. The outer contour of the float (1) can be round as shown on the drawings or angular.

The upper part of the vertical column (2) is arranged to accommodate the bearing unit's (4) axial movement. The middle and lower part of the vertical column (2) may be a cylinder or pipe with a round or multi-angular cross section.

The vertical column (2) may be equipped with a chamber (2b) or buoyancy elements to provide the required buoyancy. The magnitude of the buoyancy force can be varied so that the column (2) floats independently of the float (1) or exerts an upward force on the float (1). Another alternative is that the float (1) may carry some or all of the vertical column's (2) weight. The distance from the mechanisms' (5, 6, 7, 8) pivotal axes to the float's (1) own pivotal axis in the water will affect the pivotal movement. In order to optimise the float's (1) pivotal movement, the distance from the water surface to the pivot mechanism may differ from that shown in the drawings.

Fig. 1 shows the device which includes a float (1), a vertical column (2) with a chamber (3) at its lower end, a coupling (comprising 4, 5, 6, 7and 8) and energy converters (9, 10, 11). The coupling comprises a bearing unit (4) for axial movement, bearing units for pivotal movement (5), a frame (6) and bearing units for pivotal movement (7, 8).

The float's (1) movement in the vertical column's (2) axial direction is made possible by use of the bearing unit (4). The bearing unit (4) can, for example, consist of a bearing housing with sliding, ball or roller bearings.

The float's (1) pivotal movement in relation to the vertical column (2), ie rotation about horizontal axes, is made possible by the bearing unit (4) being pivotally mounted to the frame (6) by use of bearing units (5) and by the frame (6) being pivotally mounted to the float (1) by use of bearing units (7, 8). The bearings units (5) can, for example, comprise shafts with sliding, ball or roller bearings. The sliding, ball or roller bearings can be situated in the frame (6) or in the bearing unit (4).

The bearing units (7, 8) can eg comprise shafts, bearing housing with sliding, ball or roller bearings. The sliding, ball or roller bearings can be situated in the frame (6) or in the bearing housing (8).

Energy converters (11) are arranged in connection with the bearing unit's (4) axial movement. One end of the energy converter (11) is connected to the bearing unit (4) and the other end is connected to the upper part of the vertical column (2). The relative axial movement which occurs is utilised to drive the energy converters (11).

Furthermore, energy converters (9, 10) are arranged in connection with the bearing unit's (4) pivotal movement and the frame's (6) pivotal movement. The relative pivotal movement which occurs is utilised to drive the energy converters (9, 10). The pivotal movement may be transferred by use of the shafts (5, 7) or by use of other mechanical transmission. The energy converters (9, 10) may be placed in many ways to achieve optimum results.

The float' s (1) movements in relation to the vertical column (2) is thus utilised to drive energy converters (9, 10, 11) which generate useful energy, eg electricity. As the energy flow from the waves is uneven it may be practicable to conduct the electricity to a battery or other equipment for temporary storage so that the output energy is evened out. The battery or equipment can eg be situated inside the upper part of the vertical column (2).

The device may be equipped with different control systems to regulate and optimise energy extraction and generation.

To further increase the energy production, the device may be equipped with a windmill to extract and utilise the energy in wind. The windmill may eg be placed on top of the vertical column (2).

Fig. 5 and 6 show examples of mooring for the device. The numbers (12, 13) refer to fastening points for the mooring lines/cables and (14, 15) refer to mooring lines/cables. The device can with advantage be moored to buoys or other devices which can act as springs. Horizontal wave forces will thus cause to-and-fro motion of the device which will result in relative pivotal movements of the float ( 1 ) and the vertical column (2).

Another variant of the invention in question would be to place the vertical column (2) so that its lower end is supported on the seabed or is moored to the seabed.

A further design variant of the invention in question would be to replace the chamber (3) with plates or a solid body designed to counteract movement of the vertical column (2) in various ways.

Claims

PATENT CLAIMS

1. A device for the extraction of energy from water motion, preferably ocean or sea waves, and conversion of the extracted energy into useful energy, which comprises a float (1) placed around a vertical column (2) and energy converters (9, 10, 11) which utilise the float's (1) movement in relation to the vertical column (2) to generate useful energy, characterised by the device comprising a bearing unit (4) for the float's (1) movement in the vertical column's (2) axial direction and that the device includes a universal-joint mechanism (comprising 4, 5, 6, 7 and 8) for the float's (1) pivotal movement in relation to the vertical column (2) and that the device includes minimum one energy converter (10) for utilisation of the frame's (6) pivotal movement in relation to the bearing unit (4) and that the device includes minimum one energy converter (9) for utilisation of the float's (1) pivotal movement in relation to the frame (6) and that the device includes minimum one energy converter (11) for utilisation of the bearing unit's (4) movement in the vertical column's (2) axial direction.

2. The device according to Claim 1 characterised by a coupling (comprising 4, 5, 6, 7 and 8) between the float (1) and the vertical column (2) in that the bearing unit (4) is arranged for axial movement in the vertical column's (2) axial direction and that the bearing unit (4) is pivotally mounted to the frame (6) by means of bearing units (5) and that the frame (6) is pivotally mounted to the float (1) by means of bearing units (7, 8).

3. The device according to Claims 1 or 2 characterised by the outer contour of the float (1) in the horizontal plane being circular, approximately round or angular in shape with a hole or aperture in its centre and that lower part (lc) of its cross-section, shown on section B-B of figure 7, is relatively narrow or pointed and that upper part (Id) of the cross- section is relatively wide and that the inner side wall (la) and the outer side wall (lb) are inclined in relation to the horizontal plane.

4. The device according to Claims 1, 2 or 3 characterised by the upper part of the vertical column (2) comprising bearings for the bearing unit's (4) axial movement and that the vertical column (2) includes minimum one chamber (2b) or buoyancy element and that the lower part of the vertical column (2) includes a chamber (3) which partly or completely encloses a volume of water.

5. The device according to Claims 1, 2, 3 or 4 characterised by the vertical column's (2) middle and lower part comprising a pipe or cylinder and is round or angular in cross-section.

6. The device according to Claims 1, 2, 3, 4, or 5 characterised by the lower end of the vertical column (2) being supported on the seabed or is anchored to the seabed by means of lines/cables.

7. The device according to Claims 1, 2, 3, 4, 5 or 6 characterised by the chamber (3) being replaced by a solid body or plates.

8. The device according to Claims 1, 2, 3, 4, 5, 6 or 7 characterised by the device comprising energy converters (11) which use a straight-line to-and-fro movement to generate electricity.

9. The device according to Claims 1, 2, 3, 4, 5, 6, 7 or 8 characterised by the device comprising windmill and associated generators for conversion of wind energy into electrical energy.

10. The device according to Claims 1, 2, 3, 4, 5, 6, 7, 8, or 9 characterised by the device being moored by use of one or more lines/cables to fastening points near the water surface, eg to buoys or to fastening points on shore.

AMENDED CLAIMS

[received by the International Bureau on 13 July 2001 (13.07.01); original claims 1-10 replaced by amended claims 1-9 (2 pages)]

1. A device for the extraction of energy from water motion, preferably ocean or sea waves, and conversion of the extracted energy into useful energy, which includes a float (1) placed around a vertical column (2), a bearing unit (4) for the float's (1) axial movement along the vertical column (2) and energy converters (11) which utilise the float's (1) axial movement along the vertical column (2) to generate useful energy, characterised by a universal-joint mechanism (comprising 5, 6, 7, 8) facilitating the float's (1) pivotal movement in relation to the bearing unit (4), in that the bearing unit (4) is pivotally mounted to a frame (6) by means of bearing units (5); whose turning axes are approximately perpendicular to the vertical column'*^ (2) longitudinal axis, and that the frame (6) is pivotally mounted to the float (1) by means of bearing units (7, 8); whose turning axes are approximately perpendicular to the bearing units' (5) turning axes and the vertical column's (2) longitudinal axis, and that the device is equipped with energy converters (9, 10) which utilise the float's (1) pivotal movement in relation to the vertical column (2) to generate useful energy, in that at least one energy converter (10) is mechanically connected to the bearing unit (4) and the frame (6) and that at least one energy converter (9) is mechanically connected to the float (1) and the frame (6).

2. The device according to Claim 1 characterised by the outer contour of the float (1) in the horizontal plane being circular, approximately round or angular in shape and that the float (1) has a through aperture or hole in its centre and that the lower part (lc) of the float's (1) cross-section, shown on section B-B of figure 7, is pointed or narrow in relation to the upper part (Id) and that lower part of the inner side wall (la) and thp outer side wall (lb) are inclined in relation to the horizontal plane.

3. The device according to Claims 1 or 2 characterised by the upper part of the vertical column (2) being arranged for the bearing units (4) axial movement along the vertical column (2) and that the vertical column (2) includes at least one chamber (2b) or buoyancy element to provide buoyancy and that lower part of the vertical column (2) includes at least one chamber (3) which partly or completely encloses a mass of liquid or water.

ENDED SHEET {ARTICLE 19)

4. The device according to Claims 1, 2, or 3 characterised by the vertical column's (2) middle and lower part being a pipe or cylinder and is round or angular in cross-section.

5. The device according to Claims 1, 2, 3, or 4 characterised by the device being equipped with energy converters which use a straight-line to-and-fro movement to generate electricity.

6. The device according to Claims 1, 2, 3, 4, or 5 characterised by the device being equipped with windmill and generators for conversion of wind energy into electrical energy.

7. The device according to Claims 1, 2, 3, 4, 5 or 6 characterised by the device being moored by use of one ore more lines/cables to fastening points near the water surface, eg to buoys or to fastening points onshore.

8. The device according to Claims 1, 2, 3, 4, 5, or 7 characterised by the chamber (3) being replaced by a solid body or plates.

9. The device according to Claims 1, 2, 3, 4, 5, 6, 7 or 8 characterised by the lower end of the vertical column (2) being supported on the seabed or is anchored to the seabed by use of minimum one line/cable.