Wave power generation device

Abstract

To provide a wave power generation device that can increase the amount of electricity generated. [Solution] The wave power generation device 1A is a wave power generation device that generates electricity using wave power, and comprises a float 4 floating on the sea surface 200, a support part 3 that supports the float 4 so that it can reciprocate along the Z direction (vertical direction), a power generation unit that generates electricity by the reciprocating movement of the float 4, and a reflecting wall 5 provided inland from the float 4. The reflecting wall 5 is positioned as close as possible to the float 4 with a gap between them.

Description

【Technical Field】 【0001】 The present invention relates to a wave power generation device. 【Background Art】 【0002】 Conventionally, as a power generation device that utilizes wave power, a wave energy recovery device has been proposed in which a wave energy recovery unit is provided at a location where reflected waves from a wave reflection surface on the coast converge (see, for example, Patent Document 1). In the wave energy recovery device of Patent Document 1, by recovering wave energy at a location where reflected waves converge, an improvement in energy recovery efficiency is attempted. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Laid-Open No. 58-214678 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 However, since the wavelengths of the generated waves vary, even if an energy recovery unit is provided at a location where reflected waves converge as described in Patent Document 1, at a certain wavelength, the incident wave and the reflected wave reinforce each other, but at other frequencies, the incident wave and the reflected wave cancel each other out. That is, it is difficult to improve the energy recovery efficiency regardless of the wavelength, and a further increase in the power generation amount has been desired. 【0005】 The present invention has been made in view of the above problems, and an object thereof is to provide a wave power generation device capable of increasing the power generation amount. 【Means for Solving the Problems】 【0006】 To achieve the above objective, the wave power generation device according to the present invention is a wave power generation device that generates electricity using wave power, comprising: a float floating on the surface of the sea; a support part that supports the float so that it can reciprocate along the vertical direction; a power generation part that generates electricity by the reciprocating movement of the float; and a reflecting wall provided inland from the float, wherein the reflecting wall is arranged as close as possible to the float with a gap between them. 【0007】 In a wave power generation device according to one aspect of the present invention, the sum of the dimensions of the float in the direction opposite to the reflecting wall and the float, and the distance between the reflecting wall and the float, is 1 / 4 or less of the assumed wavelength. 【0008】 In a wave power generation device according to one aspect of the present invention, the width of the reflecting wall is 30 to 80 m. 【0009】 In a wave power generation device according to one aspect of the present invention, the reflecting wall has a movable part that can move along the vertical direction so that the height of its upper end can be changed. 【0010】 To achieve the above objective, the wave power generation device according to the present invention is a wave power generation device that generates electricity using wave power, comprising a float floating on the sea surface, a support part that supports the float so that it can reciprocate along the vertical direction, and a power generation part that generates electricity by the reciprocating movement of the float, wherein the float is arranged as close as possible to the wall surface of the breakwater that extends along the vertical direction, with a gap between them. [Effects of the Invention] 【0011】 According to the wave power generation device of the present invention, the amount of power generated can be increased. [Brief explanation of the drawing] 【0012】 [Figure 1] This is a schematic plan view showing a wave power generation device according to the first embodiment of the present invention. [Figure 2]This is a schematic cross-sectional view showing a wave power generation device according to the first embodiment of the present invention. [Figure 3] This is a schematic cross-sectional view showing a wave power generation device according to a second embodiment of the present invention. [Modes for carrying out the invention] 【0013】 [First Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. Figure 1 is a schematic plan view showing a wave power generation device 1A according to the first embodiment of the present invention, and Figure 2 is a schematic cross-sectional view showing the wave power generation device 1A. 【0014】 As shown in Figures 1 and 2, the wave power generation device 1A according to the first embodiment of the present invention is a wave power generation device that generates electricity using wave power, and comprises a float 4 floating on the sea surface 200, a support part 3 that supports the float 4 so that it can reciprocate along the Z direction (vertical direction), a power generation part that generates electricity by the reciprocating movement of the float 4, and a reflecting wall 5 provided inland from the float 4. The reflecting wall 5 is positioned as close as possible to the float 4 with a gap between them. 【0015】 The wave power generation device 1A comprises a foundation 2, a support section 3, a float 4, a power generation section (not shown), and a reflecting wall 5, and is installed at a predetermined distance from the coast and is electrically connected to a power receiving facility via a submarine cable. 【0016】 In the following explanation, the vertical direction will be referred to as the Z direction, and the up and down directions within the Z direction will simply be called up and down. Furthermore, the direction along the coastline at the location where the wave power generator 1A is installed will be referred to as the Y direction, and the direction perpendicular to both the Z and Y directions (the direction from the coastline toward the open ocean) will be referred to as the X direction. In addition, the open ocean side and the inland side in the X direction will simply be referred to as the open ocean side and the inland side, and the wave W propagates from the open ocean side toward the inland side. Note that the coastline may not be straight but curved, but at least in the area where the wave power generator 1A is installed, the direction along the coastline will be referred to as the Y direction. 【0017】 The foundation 2 is a pile foundation driven into the seabed surface 100, and is provided, for example, on the seabed surface 100 at a depth of about 9 to 20 m. 【0018】 The support part 3 is a rod-shaped or cylindrical member connected to the foundation 2 and extends along the Z direction. Also, the upper end part 31 of the support part 3 is located above the sea surface 200 and is exposed by a predetermined length. Note that the height of the sea surface 200 can vary, but it is sufficient that a predetermined exposed length of the support part 3 (not less than the assumed amplitude of the float 4) is ensured at high tide. Note that the fixing structure of the foundation 2 and the support part 3 to the seabed surface 100 is not limited to the above, and a fixing structure using a block foundation may be used as in the second embodiment described later. 【0019】 The float 4 has a rectangular parallelepiped float body 41 and a guided part 42 guided by the support part 3. 【0020】 The density inside the float body 41 is lower than the density of water, and it floats on the sea surface 200 by buoyancy. The float body 41 is arranged such that each side is along the X direction, the Y direction, and the Z direction, respectively. 【0021】 The guided part 42 is a cylindrical part provided at the central part of the float body 41 in the XY plane and protrudes vertically from the float body 41. Guide rollers are provided inside the guided part 42, and the support part 3 is inserted therein. Thereby, the guided part 42 is guided along the Z direction by the support part 3. Therefore, when the float body 41 floating on the sea surface 200 moves by waves, the guided part 42 is guided by the support part 3, and the float 4 reciprocates along the Z direction. 【0022】 The power generation part generates power by utilizing the reciprocating movement along the Z direction of the float 4. For example, it may have a rack and pinion mechanism provided between the guided part 42 and the support part 3. That is, the power generation part may be configured to convert the reciprocating movement along the Z direction into a rotational movement and generate power by this rotational movement. The generated power is transmitted to the power receiving equipment via a submarine cable. 【0023】 The reflecting wall 5 is formed in a plate shape with the X direction as the thickness direction, the Y direction as the width direction, and the Z direction as the height direction, and is driven into the seabed surface 100. Note that the fixing structure of the reflecting wall 5 to the seabed surface 100 is not particularly limited, and for example, a fixing structure using a block foundation may be used. The upper end portion 51 of the reflecting wall 5 is located above the sea surface 200 and is exposed by a predetermined height. Note that the height of the sea surface 200 may vary, but it is sufficient that a predetermined height (assumed normal wave height) of the reflecting wall is ensured at high tide. 【0024】 The reflecting wall 5 has a fixing portion 52 fixed to the seabed surface 100, a movable portion 53 movably supported above the fixing portion 52 and including the upper end portion 51, and a driving portion (not shown) for driving the movable portion 53. Since the movable portion 53 can move along the Z direction, the height of the upper end portion 51 can be changed. The movable portion 53 preferably moves along the Z direction by, for example, guiding the outer peripheral surface thereof by a guide roller provided on the fixing portion 52. In FIG. 2, the state where the movable portion 53 is located at the uppermost side is shown by a solid line, and the state where the movable portion 53 is located at the lowermost side is shown by a one-dot chain line. 【0025】 The mechanism for moving the movable portion 53 is not particularly limited, but in the present embodiment, it is a mechanism using buoyancy. That is, the movable portion 53 has a cavity portion into which a gas (e.g., air) or a liquid (e.g., water) can be introduced, and the driving portion supplies a gas or a liquid to the cavity portion of the movable portion 53. During power generation operation, the driving portion supplies a gas to the cavity portion of the movable portion 53, so that the movable portion 53 rises due to buoyancy and the upper end portion 51 is located above the sea surface 200. When the movable portion 53 moves to a predetermined height, further movement is restricted by the fixing portion 52, and the movable portion 53 becomes immovable with respect to the fixing portion 52. On the other hand, for example, in stormy weather, the driving portion supplies a liquid to the cavity portion of the movable portion 53, so that the movable portion 53 descends due to gravity and the upper end portion 51 is located below the sea surface 200. 【0026】 The width (Y-direction dimension) of the reflecting wall 5 is set to half the wavelength corresponding to the wave period with the highest frequency of occurrence at the location where the wave power generation device 1A is installed. In this embodiment, the wave power generation device 1A is installed on the coast of Japan, in which case the wave period with the highest frequency of occurrence is 6 to 10 seconds, and the width of the reflecting wall 5 is 30 to 80 meters. 【0027】 The reflecting wall 5 is positioned inland relative to the support section 3 and the float 4, and is positioned as close as possible to the float body 41 of the float 4 with a gap G1 (i.e., spacing) between them (i.e., they are lined up next to each other with a gap between them). The direction in which the float 4 and the reflecting wall 5 face each other is the X direction. It is preferable to make the gap G1 as small as possible so as not to interfere with the float body 41 (for example, 30 cm or more). The lower limit of the gap G1 is such that even if marine organisms attach to the reflecting wall 5, it will not interfere with the float 4, and is determined according to the expected types of marine organisms and the expected service life of the wave power generation device 1A. 【0028】 Furthermore, the smaller the sum of the X-direction dimension of float 4 and the gap G1, the higher the power generation efficiency. However, the maximum allowable sum of the X-direction dimension of float 4 and the gap G1 is 1 / 4 of the assumed wavelength. Note that the amount of power generated per unit cost can be improved by increasing the size of the float within the range of the maximum dimensions. It is also necessary to consider that the rotational moment acting on the float increases as the X-direction dimension of float 4 approaches 1 / 4 of the assumed wavelength. The assumed wavelength is a wavelength corresponding to a wave period that occurs with a certain frequency. For example, in the coastal areas on the Pacific side of eastern Japan, the frequency of occurrence is almost zero for periods of 5s or less, but for periods of 5s to 6s, it occurs with a frequency of about 5% to 10%. Therefore, the wavelength corresponding to a period of 5.5s (47m) is used, and at this assumed wavelength, the sum of the X-direction dimension of float 4 and the gap G1 will be 11m or less. 【0029】 In Figure 1, for convenience, one float 4 is shown for one reflective wall 5. However, in this embodiment, multiple floats 4 are arranged along the Y direction, so that multiple floats 4 face one reflective wall 5. In this case, a support portion 3 is provided for each float 4. In this embodiment, the distance between two adjacent floats 4 is 1 to 2 times the width of the float 4. 【0030】 Here, we will explain in detail the operation of each part of the wave power generator 1A when it generates electricity. Waves traveling from the open ocean towards the inland side are partially reflected by the reflecting wall 5 and continue towards the open ocean. Although traveling waves may travel in a direction slightly inclined with respect to the X direction, here we will assume that they travel along the X direction (incident perpendicularly to the reflecting wall 5). Standing waves are formed by the interference of traveling waves and reflected waves. 【0031】 The wavelengths of the generated waves vary, and the positions of the nodes and antinodes of the standing wave differ depending on the wavelength. Since the reflection of the wave at the reflecting wall 5 is a free-end reflection, the position of the reflecting wall 5 becomes an antinode of the standing wave, and the node closest to the reflecting wall 5 is formed at a distance of 1 / 4 wavelength from the reflecting wall 5. In addition, in the region where the distance from the reflecting wall 5 is less than 1 / 4 of the wavelength, the amplitude of the standing wave becomes larger than the amplitude of the incident wave or the reflected wave. 【0032】 As described above, by bringing the float 4 and the reflective wall 5 as close together as possible and utilizing the antinodes of standing waves, the float 4 can be moved back and forth with a larger amplitude than when no reflective wall is provided. 【0033】 Furthermore, by making the width of the reflecting wall 5 in the Y direction finite, concentric waves are generated at the widthwise ends of the reflecting wall 5, and if the width of the reflecting wall 5 is 1 / 2 or more of the wavelength, it acts to strengthen standing waves on the open ocean side of the reflecting wall 5. 【0034】 Thus, according to the wave power generation device 1A of the first embodiment of the present invention, a reflective wall 5 is provided on the inland side relative to the float 4, and the reflective wall 5 is positioned as close as possible to the float 4 with a gap G1 between them. This allows for the formation of antinodes of standing waves near the float 4 regardless of wavelength, thereby increasing the amplitude of the float 4 and increasing the amount of power generated. 【0035】 Furthermore, because the sum of the X-direction dimension of float 4 and the gap G1 is less than 1 / 4 of the assumed wavelength, float 4 can be moved back and forth with a larger amplitude than when a reflective wall is not provided, thereby further increasing the amount of power generated. 【0036】 Furthermore, because the width of the reflecting wall 5 is 30 to 80 m, for frequently occurring waves, the concentric waves generated at the widthwise ends of the reflecting wall 5 can strengthen the standing waves, thereby further increasing the amount of power generated. 【0037】 Furthermore, multiple floats 4 face a single reflecting wall 5, and the distance between two adjacent floats 4 is 1 to 2 times the width of the float 4, thereby increasing the amount of power generated per float 4. This can be done. Furthermore, the amount of power generated per unit cost can be improved by installing as many floats as possible within a range where they do not come into contact with each other. 【0038】 Furthermore, by making it possible to change the height of the upper end 51 of the reflecting wall 5, it is possible to suppress excessive wave forces acting on the reflecting wall 5 during rough weather. 【0039】 [Second Embodiment] A second embodiment of the present invention will be described with reference to the drawings. Figure 3 is a schematic cross-sectional view showing a wave power generation device 1B according to the second embodiment of the present invention. Hereafter, components having the same function as in the first embodiment will be denoted by the same reference numerals and their descriptions will be omitted. 【0040】 As shown in Figure 3, the wave power generation device 1B according to the second embodiment of the present invention is a wave power generation device that generates electricity using wave power, and comprises a float 4 floating on the sea surface 200, a support part 6 that supports the float 4 so that it can reciprocate along the Z direction (vertical direction), and a power generation unit that generates electricity by the reciprocating movement of the float 4. The float 4 is positioned as close as possible to the wall surface 301 of the breakwater 300 that extends along the Z direction (vertical direction), with a gap between them. 【0041】 Wave power generation device 1B differs from the first embodiment mainly in the shape of the support section and the presence or absence of the reflecting wall 5. 【0042】 Of the breakwater 300 installed on the coast, the wall surface facing the open sea and extending along the Z direction is designated as the vertical wall surface 301, and the surface facing inland and upward is designated as the upper surface 302. The breakwater 300 is constructed of concrete. 【0043】 The support section 6 has a lower fixing section 61, an upper fixing section 62, and a shaft section 63. The lower fixing section 61 of the support section 6 is fixed to the seabed surface 100 via the block foundation 2B, and the upper fixing section 62, which is fixed so as to rest on the upper surface 302, extends along the X direction toward the open ocean. The shaft section 63 connects the open ocean end of the lower fixing section 61 and the upper fixing section 62 and extends along the Z direction. 【0044】 The shaft portion 63 of the support portion 6 is inserted into the cylindrical guided portion 42 of the float 4, and the float 4 is supported so that it can reciprocate along the Z direction. 【0045】 Furthermore, when the wave power generation device 1B is positioned near the breakwater 300 as in this embodiment, not only the upper end of the support portion but also the lower end may be fixed to the breakwater 300 (especially the vertical wall surface 301). 【0046】 The gap G2 between the float 4 and the vertical wall surface 501 may be the same size as the gap G1 in the first embodiment. Also, the sum of the X-direction dimension of the float 4 and the gap G2 may be the same size as the sum of the X-direction dimension of the float 4 and the gap G1 in the first embodiment. 【0047】 According to the wave power generation device 1B of the second embodiment of the present invention, the amount of power generated can be increased, similar to the wave power generation device 1A of the first embodiment. 【0048】 Furthermore, by utilizing the vertical wall surface 301 of the breakwater 300, the device can be simplified compared to the case where a dedicated component for reflection is provided. 【0049】 Furthermore, the present invention is not limited to the embodiments described above, and includes other configurations that can achieve the objectives of the present invention, including the following modifications. For example, in the first embodiment described above, the width of the reflective wall 5 was assumed to be 30 to 80 m, but in the case of waves with a short wavelength that occur frequently... In some cases, the width of the reflecting wall may be less than 30m, or if the wavelength of frequently occurring waves is long, the width of the reflecting wall may be greater than 80m. Furthermore, the amount of power generated per unit cost may be improved by increasing the width of the reflecting wall and facing more floats. 【0050】 Furthermore, in the first embodiment described above, multiple floats 4 face one reflective wall 5, and the distance between two adjacent floats 4 is 1 to 2 times the width of the float 4. However, the distance between floats is not limited to this. For example, the amount of power generated per unit cost may be improved by making the distance between floats less than the width of the floats. Alternatively, the distance between floats may be made greater than twice the width of the floats to suppress the influence that the floats have on each other. Also, a configuration in which only one float faces one reflective wall is possible. Furthermore, in the second embodiment described above, multiple floats 4 face a breakwater 300, but the distance between two adjacent floats 4 may be the same as in the first embodiment. 【0051】 Although embodiments of the present invention have been described above, the present invention is not limited to the wave power generation apparatus according to the above embodiments, but includes all embodiments included in the concept and claims of the present invention. Furthermore, each component may be selectively combined as appropriate to achieve at least some of the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiments may be appropriately changed depending on the specific use of the present invention. [Explanation of symbols] 【0052】 1A, 1B... Wave power generation device, 3, 6... Support section, 4... Float, 5... Reflecting wall, 200... Sea surface, 300... Breakwater, 301... Vertical wall surface, G1, G2... Gap

Claims

[Claim 1] A wave power generation device that generates electricity using wave power, Floats floating on the surface of the sea, A support portion that supports the float so that it can reciprocate along the vertical direction, A power generation unit that generates electricity by the reciprocating movement of the float, The float comprises a reflective wall provided on the inland side, The wave power generation device is characterized in that the reflective wall is positioned as close as possible to the float with a gap between them. [Claim 2] The wave power generation apparatus according to claim 1, characterized in that the sum of the dimensions of the float in the direction opposite to the reflecting wall and the float, and the distance between the reflecting wall and the float, is 1 / 4 or less of the assumed wavelength. [Claim 3] The wave power generation device according to claim 1 or 2, characterized in that the width of the reflecting wall is 30 to 80 m. [Claim 4] Multiple floats are arranged along the width direction of the reflective wall and facing one of the reflective walls, The wave power generation device according to claim 1 or 2, characterized in that the distance between two adjacent floats is 1 to 2 times the width of the float. [Claim 5] The wave power generation apparatus according to claim 1 or 2, characterized in that the reflective wall has a movable part that can move along the vertical direction so that the height of its upper end can be changed. [Claim 6] A wave power generation device that generates electricity using wave power, Floats floating on the surface of the sea, A support portion that supports the float so that it can reciprocate along the vertical direction, The system comprises a power generation unit that generates electricity through the reciprocating movement of the float, The wave power generation device is characterized in that the floats are positioned as close as possible to the vertically extending wall surface of the breakwater, with a gap between them.

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