Panel arrangement of a wave energy converter

Abstract

A panel arrangement of a wave energy converter (WEC), which panel arrangement comprises a panel (2) reciprocating about a pivot shaft (2a) on bearings (2b), and a connection mechanism (5) with a lever arm (5a), which is arranged to transfer the reciprocating motion of the panel (2) to one or more power units (3) of the WEC, which panel (2) comprises at least a top part (7) and a bottom part (9). In the front view of the panel (2) the bottom part (9) of the panel (2) is narrower than the top part (7) of the panel (2).

Description

[0001] PANEL ARRANGEMENT OF A WAVE ENERGY CONVERTER

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a panel arrangement of a wave energy conversion apparatus described in the preamble of claim 1 , in which apparatus the energy capture is improved.

[0004] The invention is suited very well for instance to be used in a wave energy conversion apparatus comprising a reciprocating panel or flap or essentially plate-like wing element, hereafter called a panel, which panel is hinged at its lower edge to enable a reciprocating movement caused by wave energy or tidal energy of seawater as shown, for example, in a patent publication No. WO2017029425 (A1). The wave energy or tidal energy captured is further converted with a conversion unit to electric energy, for instance.

[0005] BACKGROUND OF THE INVENTION

[0006] According to prior art, there are various types of wave energy conversion (WEC) apparatuses that comprise panels reciprocating with ocean waves. These apparatuses convert the wave energy to electricity by capturing the energy of the oscillatory motion of the reciprocating panels using e.g., hydraulic systems for power take-off (PTO).

[0007] The efficiency of these types of WEC apparatuses is dependent, among other things, on the size and shape of the panel. The reciprocating panel loses energy due to viscous effects as a result of the relative velocity between the panel and water. These losses can be reduced by modifying the edge profiles of the panel. Accordingly, in prior art, there are apparatuses with panels of various shapes. For example, in the systems presented in patent publications WO2010049708 (A2) and W02006100436 (A1) the panel top edges and side edges or ends are shaped in various ways. In these solutions, however, the structures are under heavy strain as the bearings are far from each other and allow therefore the lower part of the panel to bend, which causes stress. In addition, the panels of the prior art solutions are large and heavy, adding to material costs.

[0008] AIM OF THE INVENTION

[0009] The aim of the present invention is to eliminate the drawbacks described above and to achieve a panel arrangement of a wave energy converter that is lighter, cost-effective, energy efficient and durable by shaping the panel in such a way that the energy capture is optimised, and the amount of energy losses and strains are minimal. The panel arrangement of a wave energy converter according to the invention is characterized by what is presented in the characterization part of claim 1 . Other embodiments of the invention are characterized by what is presented in the other claims.

[0010] BRIEF DESRCRIPTION OF THE INVENTION

[0011] To achieve the aim of the invention a panel arrangement of a wave energy converter (WEC) comprises a panel reciprocating about a pivot shaft on bearings, and a connection mechanism with a lever arm, which is arranged to transfer the reciprocating motion of the panel to one or more power units of the WEC, which panel comprises at least a top part and a bottom part. Advantageously, in the front view of the panel the bottom part of the panel is narrower than the top part of the panel.

[0012] ADVANTAGES OF THE INVENTION

[0013] The main advantage of the panel arrangement of a wave energy converter according to the invention is increased energy capture due to better positioning of the surface area and smaller energy losses, and thus higher efficiency compared to prior art solutions. This advantage is achieved by panel end shapes and extensions i.e., optimal overall form of the panel, as well as a lighter panel, which is achieved by placing the bearing points of the panel closer together, which allows a more durable panel to be manufactured with less material. The smaller bearing distance, as well as the lighter panel cause less strain to the panel bearings. In addition, the design of the ends of the panel enables a narrower i.e., lighter panel to be manufactured. Also, the foundation can be narrower as the bearings are not that far from each other. In this way the foundation attracts significantly less wave loading. Another advantage of the panel according to the invention is that the lowest part or bottom part of the panel i.e., the shaft block is shorter. This is a great advantage since the shaft block is a precision machined mechanized part. In addition, since the shaft block is lighter and shorter its transportation is more convenient and it can be manufactured in proper conditions, for instance, in the manufacturing factory or in other appropriate places, whereas the other parts, which are bigger and heavier, are manufactured at the operation site. LIST OF FIGURES

[0014] In the following, the invention will be described in detail by the aid of examples by referring to the attached simplified and diagrammatic drawings, wherein

[0015] Fig. 1 presents in an oblique top view a wave energy converter according to one preferred embodiment of the invention,

[0016] Fig. 2 presents the wave energy converter according to Figure 1 in a front view,

[0017] Fig. 3 presents a panel of the wave energy converter according to Figure 1 in a front view and separated into three main parts,

[0018] Fig. 4 presents in an oblique top view a panel according to another preferred embodiment of the invention,

[0019] Fig. 5 presents in an oblique top view a panel according to yet another preferred embodiment of the invention,

[0020] Fig. 6 presents in a front view a panel according to yet another preferred embodiment of the invention,

[0021] Fig. 7 presents the wave energy converter according to Figure 1 in a side view,

[0022] Fig. 8 presents the wave energy converter according to the invention equipped with one of the panels of Figures 4, 5 or 6, and

[0023] Fig. 9 presents in a top view and cut in the middle of their width some panels according to the invention equipped with different kind of side or end extensions.

[0024] DETAILED DESRCRIPTION OF THE INVENTION

[0025] When describing the embodiments of the invention and referring to the figures mentioned above the expression “front view” means the view of the wave energy converter in the reciprocating direction of the panel, and the expression “side view” means the view of the wave energy converter perpendicular to the reciprocating direction of the panel. In addition, the width of the panel and its components is measured and expressed in the direction perpendicular to the reciprocating direction of the panel, and the thickness of the panel and its components is measured and expressed in the reciprocating direction of the panel. And expressions relating to height mean height measurements when the panel is in a vertical position.

[0026] Fig. 1 presents a wave energy converter according to one preferred embodiment of the invention viewed obliquely from above. The wave energy converter comprises a founda- tion 1 , a panel arrangement with a reciprocating panel 2, and one or more PTO units 3. Each PTO unit 3 of the wave energy converter comprises one or more power units 3a and a power transmission system 4.

[0027] The panel 2 is arranged to reciprocate about its pivot shaft 2a with a rotation axis 2c, which pivot shaft 2a is attached on the foundation 1 by its bearings 2b. In addition to the panel 2 the panel arrangement comprises at least one connection mechanism 5 with a lever arm 5a and a coupling unit 5b to couple the reciprocating panel 2 to the power transmission system 4.

[0028] Preferably, the panel arrangement also comprises arch shaped flow guides 6, which are immovably attached to the foundation 1 below the panel 2, one below each end of the panel 2.

[0029] The power transmission system 4 may comprise, for example, a chain drive system comprising at least a cylindrical power transmission shaft 4a, the central axis of the power transmission shaft 4a being preferably substantially parallel with the rotation axis of the pivot shaft 2a of the panel 2.

[0030] Fig. 2 presents the wave energy converter substantially similar to the wave energy converter according to Fig. 1 viewed from the front, or in the direction of the reciprocating motion of the panel 2, and Fig. 3 presents the panel 2 of the wave energy converter according to Fig. 2 viewed from the front, or in the direction of the reciprocating motion of the panel 2, and separated into its three main parts 7, 8 and 9.

[0031] Advantageously, the panel 2 comprises three main parts which are connected to each other; a first part or a top part 7, a second part or a middle part 8 and a third part or a bottom part 9.

[0032] The bottom part 9 is a separately precision machined structure that comprises a short pivot shaft 2a at its each end. In addition to the arrangement of the pivot shaft 2a, the bottom part 9 comprises a connection structure 9a to attach the bottom part to the panel 2.

[0033] The main parts 7, 8, 9 of the panel 2 are adjacent to each other so that when the panel 2 is in its vertical position the first part 7 is the topmost part, the second part 8 is fastened under the first part 7 and the third part 9 is fastened under the second part 8. Advantageously, but not necessarily, all three parts 7-9 are coaxially and symmetrically placed in relation to their vertical central axis both in the width direction and thickness direction of the panel 2.

[0034] The main parts 7, 8 and 9 may be independent from each other so that depending on the conditions on an installation site different size and looking panels 2 may be construed by varying the shapes of the main parts which are attached together. For instance, the height, width and thickness, and also the shape and cross-section may vary. Thus, for instance the bottom part 9 could be almost always the same, maybe only one or two size variants, the middle part 8 could vary in its width, height and shape in the direction perpendicular to the reciprocating motion of the panel 2, and the top part 7 with its side extensions 7a could vary the most, at least in its width, height and shape in the direction perpendicular to the reciprocating motion of the panel 2 and also the cross-section in the reciprocating direction of the panel 2.

[0035] As to the energy capture, the top part 7 is the most important part of the panel 2. Its surface area against the waves must be as large and effective as possible to capture as much energy as possible. In addition, the top part 7 comprises advantageously on its each side edge or end a side extension 7a which may extend sideways, i.e., in the direction perpendicular to the reciprocating direction of the panel, outwards from the top part 7. The side extensions 7a may at the same time also extend in the reciprocating direction of the panel 2 and also in the height direction of the panel 2. Each side extension 7a may at the same time extend into opposite directions, for instance upwards and downwards from the edges of the top part 2 when the panel is in a vertical position. The side extensions 7a may be described as protuberances of different shapes extending different direction outwards from the end surface of the top part 7. The side extensions 7a are arranged to enlarge the total surface area of the panel 2 to improve the energy capture. Advantageously, the addition of the surface area is made to area of the panel 2 which is farther from the rotation axis of the panel 2 and closer to the surface of the water, and which even partially rises above the surface of the water.

[0036] Preferably, also the top part 7, or at least a part of it, is the thickest part of the panel 2 and forms a hollow or a mainly hollow buoyant element for the panel 2. However, when viewed from the side the side extensions 7a may also extend outwards from the top part 7 in its thickness direction.

[0037] Preferably, the middle part 8 comprises in its lower section a connection arrangement 8a to make the connection to the bottom part 9 possible. The bottom part 9 is fastened with its upper edge to the lower edge of the middle part 8 by the help of the connection arrangement 8a. The width of the middle part 8 may vary but preferably the middle part 8 is either entirely or at least partly narrower than the upper part 7. In order to make the panel 2 lighter, the middle part 8 has been made lighter. In this embodiment, this has been done by bevelling the lower corners 8b of the middle part 8 so that the height hi of the ends of the middle part 8 is shorter than the height h2 of the central area of the middle part 8 when the panel 2 is in its vertical position. In this case, the lower corners of the vertical ends of the middle part 8 are further from the pivot shaft 2a than the lower edge of the central area of the middle part 8. In this embodiment the width of the lower edge of the middle part 8 is smaller than the width of the upper edge of the middle part 8. This makes the middle part 8 lighter which improves the energy capture. The outline shape of the side edges of the middle part 8 can be also different from the linear shape shown in Figs. 4-6. For instance, it can be curvilinear i.e., concave, convex or some other kind of curve, or it can be formed of a group of linear sections or curved sections or a mixture of them. In addition, the shape of the edge may be made to enforce the structure of the middle part 8 and at the same time the structure of the whole panel 2.

[0038] The flow guides 6 are immovably attached to the foundation 1 below the motion path of the panel 2, close to both ends of the bottom part 9, which can also be called a shaft block because its end extensions form the pivot shafts 2a. The flow guides 6 are like arched shelters whose upper surface is curved in the reciprocating direction of the panel 2, and preferably the flow guides 6 are arranged to cover essentially the entire empty area below the panel 2, particularly the empty area below both sides of the middle part 8 of the panel 2. When viewed from the front the contour of the upper surface of the flow guides 6 follows the shape of the lower edges of the middle part 8 leaving a small gap 6a between the upper surface of the flow guides 6 and the lower edges of the middle part 8.

[0039] When viewed from the side the radius of the upper surface of the flow guides 6 follows the circular motion path of the lower edge of the middle part 8 of the panel 2 at the distance of the width of the gap 6a. The flow guides 6, for their part, enable the panel 2 to be made partially narrower and therefore lighter without losing the capturing power.

[0040] Figures 4-6 present three slightly different embodiments of the invention, which can be used in a wave energy converter. Each panel 2 in Figures 4-6 comprises a tubular top part 7 with a curved top extension 7b which extends upwards from the tubular top part 7. Each panel 2 in Figures 4-6 comprises also a middle part 8 whose width decreases from the top part 7 towards the bottom part 9.

[0041] The only difference between the panels 2 in Figures 4-6 may be the shape and size of the side extensions 7a. In the panels 2 in Figures 4 and 5 the side extensions 7a are flat- bottomed and tubular with the greatest diameter substantially the same as the diameter of the tubular section of the top part 7. In the solution of Fig. 4 the length of side extension 7a is shorter than the corresponding length in the solution of Fig. 5. In the solution of Fig. 6 the side extensions 7a are round-bottomed like a calotte, and tubular with the greatest diameter substantially the same as the diameter of the tubular section of the top part 7.

[0042] Preferably, also in these panels 2 the tubular top part 7, or at least a part of it, is the thickest part of the panel 2 and forms a mainly hollow buoyant element for the panel 2.

[0043] Also, the panel arrangement of Figs. 4-6 may comprise the same kind of arched flow guides 6 as mentioned above, which flow guides 6 are immovably attached to the foundation 1 below the panel 2, at both ends of the bottom part 9. Also, in this case the flow guides 6 may be like arched shelters whose upper surface is curved in the reciprocating direction of the panel 2, and preferably the flow guides 6 are arranged to cover essentially the entire empty area below the panel 2, particularly the empty area below both sides of side extensions 7a of the tubular top part 7. When viewed from the front the height of the flow guides 6 is fitted to the circular path of the lower edge of the side extensions 7a so that there is a small gap between the upper surface of the flow guides 6 and the lower edges of the side extensions 7a.

[0044] When viewed from the side the radius of the upper surface of the flow guides 6 follows the circular motion path of the lower edge of the side extensions 7a of the panel 2 at the distance of the width of the gap. The panels 2 of Figs. 4-6 may also comprise middle parts 8 as is shown in Figs. 2 and 3.

[0045] In that case the flow guides 6 may be like the flow guides 6 shown in Fig. 2.

[0046] Fig. 7 presents the wave energy converter according to Fig. 1 or Fig. 2 viewed from the side, or in the direction perpendicular to the reciprocating motion of the panel 2, and Fig. 8 presents the wave energy converter having a panel arrangement according to one of the Figs. 4-6 viewed from the side, or in the direction perpendicular to the reciprocating motion of the panel 2.

[0047] The panel 2 is attached either from its one end face or its both end faces to the power transmission system 4 of the wave energy converter by a connection mechanism 5 at a distance towards the top part 7 of the panel 2 from the rotation axis 2c of the panel 2. The connection mechanism 5 is arranged to transfer the motion of the reciprocating panel 2 to the power transmission system 4, for instance by rotating the power transmission shaft 4a. The connection mechanism 5 comprises at least a lever arm 5a attached from its lower end to the power transmission shaft 4a, or a corresponding power transmission mechanism, and from its upper end to the coupling unit 5b of the panel arrangement.

[0048] Advantageously, the coupling unit 5b is attached on the end face of the panel 2, either at the top part 7 of the panel or at its side extension 7a, or at the upper part of the middle part 8. Preferably, the coupling unit 5b is attached above the horizontal centreline of the panel 2 calculated from the rotation axis 2c of the panel 2 to the top of the top part 7 of the panel 2.

[0049] In the wave energy converter according to Fig. 8 the upper end of the lever arm 5a of the connection mechanism 5 is attached to the coupling unit 5b that is advantageously attached to the tubular side extension 7a. The coupling unit 5b may have been attached to a single point on the surface of the tubular side extension 7a or with a fastening ring 5c around the tubular side extension 7a. In the embodiment of Fig. 8 the coupling unit 5b may also have been attached to the end face of the middle part 8 of the panel 2 in the same way as has been done in the solution of Fig. 7. In that case, the upper end of the lever 5a is attached to the end face of the middle part 8 of the panel 2.

[0050] When the distance of the bearings 2b is much shorter that the width of the panel 2 it is advantageous to attach the upper end of lever arm 5a to the panel 2 as far from the rota- tion axis 2c as possible. This helps in minimizing strains in the structure. A practicable minimum distance from the rotation axis 2c to the coupling unit 5b is greater than the distance from the rotation axis 2c to the horizontal centreline of the panel 2 calculated from the rotation axis 2c of the panel 2 to the top of the top part 7 of the panel 2.

[0051] Suitably, however, the distance from the rotation axis 2c to the attaching point of the upper end of lever arm 5a is less than the distance from the rotation axis 2c to the same horizontal centreline multiplied by a number between 1 ,2 to 1 ,8; suitably 1 ,4 to 1 ,6; preferably by 1 ,5. For example, if the distance from the rotation axis 2c to the horizontal centreline of the panel 2 is S meters, the preferable distance from the rotation axis 2c to the attaching point of the upper end of lever arm 5a is about S*1 ,5 meters.

[0052] The attaching point of upper end of lever arm 5a is in the coupling unit 5b. Thus, what is mentioned about the distance above also applies the corresponding distance of the coupling unit 5b.

[0053] Preferably, at least the upper part of the side extensions 7a is above the water surface 10 when the panel 2 is in its vertical position.

[0054] Advantageously, when viewing from the side the top part 7 of the panel 2 is at its thickest point thicker than the middle part 8 of the panel, as can be seen in Figs. 7 and 8. In the cross-section, the top part 7 of the panel 2 may advantageously be in the shape of a rhombus with rounded corners, which is at its tip when the panel 2 is in a vertical position. In a vertical position, the upper part of the top part 7 above the thickest point may be higher than the lower part of the top part 7. In addition, the top part 7 may be asymmetrical in its cross-section also in other ways. The mean water level 10 reaches advantageously just below the upper tip of the top part 7 of the panel 2 when the panel is at its vertical position. The cross-section of the top part 7 may also be circular as shown in Fig. 8, or oval or some other hollow shape.

[0055] In order to achieve as good as possible capture of wave energy the top part 7 with its side extensions 7a at its side walls or ends is the broadest of the three main parts 7-9 mentioned above. In that case the greatest width of the top part 7 with its side extensions 7a is bigger than the width of the middle part 8 and the width of the bottom part 9. The shape and size of the side extensions 7a may vary, as is shown as an example in Fig. 9. However, the variations are not limited to the examples of Fig. 9.

[0056] Fig. 9 presents in a top view some panels 2 according to the invention equipped with different kind of side extensions 7a. The panels are cut in the middle so that only the end areas of the panels are shown. Although the panels 2 shown are similar to panel 2 in Fig. 1 , their cross-sectional shape may also be different. The top part 7 of the panels 2 and / or the extensions 7a can also be tubular in their cross-section as shown in Figs. 4-6.

[0057] Preferably, the cross-sectional shape of the side extensions 7a follows either partially or completely the cross-sectional shape of the upper part 7 and may be in the thickness direction of the panel 2 either narrower, equal or broader than the largest width of the top part 7 of the panel 2. The cross-sectional shape of the side extensions 7a may also be ellipsoidal or alike.

[0058] Fig. 9A presents a panel 2 with side extensions 7a the shape of which is like an inflated membrane attached from its edges to the end face of the top part 7, following the shape of the end face of the top part. In case the cross-section of the top part 7 is circular the shape of the side extensions 7a is a spherical cap with the largest diameter substantially equal to the diameter of the top part 7.

[0059] Fig. 9B presents a panel 2 with side extensions 7a whose shape is substantially like the shape of the side extensions 7a of Fig. 9A but now the outermost part of the side extensions 7a is flat. Viewed from above, the shape of the side extensions 7a in cross-section is like the shape of a circle segment. In case the cross-section of the top part 7 is circular the shape of the side extensions 7a is a spherical segment with the largest diameter substantially equal to the diameter of the top part 7.

[0060] Fig. 9C presents a panel 2 with side extensions 7a where the shape of the outermost part is substantially like the shape of the side extensions 7a of Fig. 9B but now between the outermost part and top part 7 each side extension 7a has an intermediate part 7c with a semi-circular cross-section which intermediate part 7c extends in the thickness direction of the panel 2 outside the panel, following the edges of the end face of the panel 2. Fig. 9D presents a panel 2 with side extensions 7a the shape of which is like a pipe with a relatively large diameter attached from its edges to the end face of the top part 7, following the shape of the end face of the top part. In case the cross-section of the top part 7 is circular the shape of the side extensions 7a is like a torus. The outer edge of the side extensions 7a may extend outside the edges of the end face of the top part 7 in the thickness direction of the panel 2.

[0061] Fig. 9E presents a panel 2 with side extensions 7a whose shape can be described in the same way as the shape of the side extensions 7a of Fig. 9A but now the outermost edges of the side extensions 7a extend in the thickness direction of the panel 2 outside the panel, following the edges of the end face of the panel 2.

[0062] The cross-sectional shape of the side extensions 7a is selected so that it is optimal in terms of flow technology and panel 2 durability.

[0063] The bottom part 9 is the lowermost part of the three main parts 7-9 of the panel 2. In the direction perpendicular to the reciprocating motion of the panel 2, the bottom part 9 is shorter than the top part 7 and middle part 8 so that in the front view of the panel 2 the bottom part 9 of the panel 2 is narrower than the top part 7 and middle part 8 of the panel 2. This also makes the panel 2 lighter because the bottom part 9 is lighter than in prior art solutions. Bending of the bottom part 9 is naturally restricted by the smaller distance between the bearings.

[0064] In the front view the width of the bottom part 9 may be less than 80 % of the width of the top part 7, suitably less than 60 % of the width of the top part 7 and preferably even less than 50 % of the width of the top part 7. The pivot shaft 2a is in a fixed connection with the bottom part 9, so the distance between the bearings 2b of the pivot shaft 2a depends on the length of the bottom part 9. In that case, the distance between the bearings 2b of the pivot shaft 2a is smaller than the width of top part 7. Preferably, also the distance between the bearings 2b of the pivot shaft 2a is smaller than the greatest width of middle part 8. Advantageously, the distance between the bearings 2b of the pivot shaft 2a may be less than 80 %, suitably less than 60 % and preferably less than 50 % or even 40 % of the width of the top part 7 + an appropriate gap between the ends of the bottom part 9 and the bearing housings. Because of the pivot shaft 2a is in fixed connection with the bottom part 9 the bottom part 9 must be machined precisely. The easiest way to machine it is performing the machining in the manufacturing factory or machining workshop. This can be done because the size of the bottom part 9 is small in relation to the sizes of the top part 7 and middle part 8, which can be constructed near the installation site. The weight and size of the bottom part 9 may be so small that after machining it can be easily transported to the installation site.

[0065] Preferably, the pivot shaft 2a comprises two relatively short pieces of shafts which are placed precisely co-axially with each other, and which extend outwards from the ends of the bottom part 9. The first pivot shaft extends outwards from the first end of the bottom part 9 and the second pivot shaft extends outwards from the second end of the bottom part 9. Thus, as a matter of fact, the bottom part 9 and the two short pieces of the pivot shaft 2a form the pivot shaft unit of the panel 2. Necessarily, one long and heavy pivot shaft is not needed, but in certain conditions it can be used.

[0066] It is obvious to the person skilled in the art that the invention is not restricted to the examples described above but it may be varied within the scope of the claims presented below. Thus, for example, the structure and shape of the panel, its side extensions and main parts can be different from what is presented. For example, the cross-section of the top part may be different from what is presented.

[0067] In addition, it is obvious to a person skilled in the art that the side, top and bottom edges of the panel may comprise different kinds of side extensions to guide the water flow and to improve the energy capture.

Claims

CLAIMS1. A panel arrangement of a wave energy converter (WEC), which panel arrangement comprises a panel (2) reciprocating about a pivot shaft (2a) on bearings (2b), and a connection mechanism (5), which is arranged to transfer the reciprocating motion of the panel (2) to one or more power units (3) of the WEC, which panel (2) comprises at least a top part (7) and a bottom part (9), characterized in that in the front view of the panel (2) the bottom part (9) of the panel (2) is narrower than the top part (7) of the panel (2).

2. A panel arrangement of the wave energy converter according to claim 1 , characterized in that the panel (2) comprises a middle part (8) between the top part (7) and the bottom part (9) which middle part (8) is in the front view of the panel (2) at least partially narrower than the top part (7) of the panel (2).

3. A panel arrangement of the wave energy converter according to claim 2, characterized in that the lower section of the middle part (8) is in the front view of the panel (2) narrower than the top section of the middle part (8).

4. A panel arrangement of the wave energy converter according to claim 2 or 3, characterized in that the lower section of the middle part (8) is in the front view of the panel (2) symmetrically narrower than the upper section of the middle part (8).

5. A panel arrangement of the wave energy converter according to any of the claims above, characterized in that the distance between the bearings (2b) of the panel (2) is smaller than the width of the panel (2).

6. A panel arrangement of the wave energy converter according to any of the claims above, characterized in that the distance between the bearings (2b) of the panel (2) is smaller than the width of the top part (7) of the panel (2).

7. A panel arrangement of the wave energy converter according to any of the claims above, characterized in that the distance between the bearings (2b) of the panel (2) is smaller than the largest width of the middle part (8) of the panel (2).

8. A panel arrangement of the wave energy converter according to any of the claims above, characterized in that the distance between the bearings (2b) of the panel (2) is between 40-80 % of the largest width of the panel (2).

9. A panel arrangement of the wave energy converter according to any of the claims above, characterized in that the distance between the bearings (2b) of the panel (2) is between 40-80 % of the largest width of the top part (7) of the panel (2).

10. A panel arrangement of the wave energy converter according to any of the claims above, characterized in that the top part (7) comprises side extensions (7a) extending sideways from the end faces of the top part (7).1 1 . A panel arrangement of the wave energy converter according to claim 10, characterized in that the side extensions (7a) extend sideways from the end faces of the top part (7) in a cross-sectional shape substantially the same as the top part (7).

12. A panel arrangement of the wave energy converter according to any of the claims above, characterized in that the connection mechanism (5) comprises a lever arm (5a) and the upper end of the lever arm (5a) is attached to the panel (2) at a distance from the rotation axis (2c) of the panel (2) which distance is greater than the distance from the rotation axis (2c) to the horizontal centreline of the panel (2).

13. A panel arrangement of the wave energy converter according to claim 12, characterized in that the upper end of lever arm (5a) is attached to the panel (2) at a distance from the rotation axis (2c) of the panel (2) which distance is less than the distance from the rotation axis (2c) to the horizontal centreline of the panel (2) multiplied by 1 ,8.

14. A panel arrangement of the wave energy converter according to claim 12 or 13, characterized in that the upper end of lever arm (5a) is attached to the panel (2) through a coupling unit (5b) that is attached to end face of the panel (2).

15. A panel arrangement of the wave energy converter according to claim 12, 13 or 14, characterized in that the upper end of lever arm (5a) is attached to the panel (2) through a coupling unit (5b) that is attached to end face of the top part (7) of panel (2) or to end face of the middle part (8) of panel (2).

16. A panel arrangement of the wave energy converter according to claim 12, characterized in that the upper end of lever arm (5a) is attached to the panel (2) through a coupling unit (5b) that is attached to a side extension (7a) of the panel (2).

17. A panel arrangement of the wave energy converter according to any of the claims above, characterized in that the panel arrangement comprises flow guides (6) arranged to cover essentially the entire empty area below lower corners of the panel (2).

18. A panel arrangement of the wave energy converter according to claim 17, character- ized in that the flow guides (6) are immovably attached to the foundation (1 ) below the motion path of panel (2), close to both ends of the bottom part (9).

19. A panel arrangement of the wave energy converter according to claim 17 or 18, characterized in that the flow guides (6) are arched shelters whose upper surface is curved in the reciprocating direction of the panel (2).

20. A panel arrangement of the wave energy converter according to claim 17, 18 or 19, characterized in that when viewed from the front the contour of the upper surface of the flow guides (6) follows the shape of the lower edges of the middle part (8) leaving a small gap (6a) between the upper surface of the flow guides (6) and the lower edges of the middle part (8).

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