Water power generation device

Abstract

To efficiently generate power from water flow stably even in an environment where a direction of water flow changes.SOLUTION: A water flow power generation device 1 is composed of: a pillar; a hollow rotatable support 4 connected to the pillar; a rotor 8; a rotor support member 9 that supports the rotor 8; a shaft 11; and a generator 20. The shaft 11 that rotates together with the rotor passes through the inside of the rotor support member 9 and is connected to the generator 20.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a water current power generation device.

Background Art

[0002] It is also said that there is energy of several hundred TWh per year in ocean currents around the world. Since ocean currents are more stable than the fluctuations of sunlight and wind power, power generation using ocean currents has attracted attention as a power generation method with stability. Furthermore, since ocean current power generation does not emit carbon dioxide CO2, it has also attracted attention as power generation using natural energy with an extremely small environmental load. Conventionally, there has been a technology for converting the kinetic energy of water flow into electrical energy and generating electricity by rotating a rotating body such as a propeller using the water flow in the sea or a river.

[0003] Patent Document 1 describes, as a technology for generating electricity using tidal currents, a support rod is provided at a fixed position in the sea, a screw blade that rotates by receiving the tidal current is provided on the support rod, and the rotational force of the screw blade rotated by the tidal current drives a generator in a station provided on the sea surface to generate electricity. The cylindrical rod supporting the screw blade is rotatably attached to the support rod so that the screw blade is in a posture facing the tidal current.

[0004] Patent Document 2 describes a technology in which an underwater rotating body is arranged on a vertical member fixed to the seabed, and the rotational energy obtained by the sea current rotating the underwater rotating body is transmitted to a generator on the sea. Since the underwater rotating body and the support portion are connected by a universal joint mechanism, the rotating body can change its orientation in all directions of up, down, left, and right.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the invention of Patent Document 1, the transmission and generator are arranged in a floating station on the sea, and a rotating force transmission member such as a gear is required to transmit the rotational energy received by the screw blades from the tidal current to the transmission and generator on the sea. When rotation is transmitted using a rotating force transmission member, the mechanism becomes complicated and energy loss may occur.

[0007] In addition, although the invention of Patent Document 2 can freely change the direction of the underwater rotating body according to the change in the direction of the ocean current flow, since it is connected by a small contact point called a universal joint mechanism, it is difficult to ensure sufficient strength, and there is a risk of joint breakage.

[0008] The present invention has been made in view of such a situation, and an object thereof is to stably generate power from water flow efficiently even in an environment where there are fluctuations in the direction of the water flow.

Means for Solving the Problems

[0009] The invention described in claim 1 includes a hollow column, a rotatable hollow rotating column connected to the column, a rotating body rotated by water flow, a rotating body support member having one end fixed to the rotating column and supporting the rotating body, and a shaft fixed to the rotating body and rotating integrally with the rotating body, and the shaft is connected to a generator through the internal space of the rotating body support member. Further, the rotating body support member has a cylindrical body extending in the direction of the rotation axis of the rotating body, and the rotating body is rotatably supported by a convex portion protruding radially outward from the rotating body support member facing a concave portion inside the rotating body. It is a water flow power generation device characterized by the above.

[0011] Claim 2 The invention described in is characterized in that the power transmission cable connected to the generator is laid in the internal space of the rotating body support member or the column. 1 to It is the water flow power generation device described in claim

[0012] Claim3 The invention described in 1 to is a water flow power generation device described in claim

Advantages of the Invention

[0014] According to the present invention, even in an environment where the direction of the water flow fluctuates, power can be stably and efficiently generated from the water flow.

Brief Description of the Drawings

[0015]

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Modes for Carrying Out the Invention

[0016] The power generation device according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments.

[0017] (First Embodiment) FIG. 1 is a perspective view showing a water current power generation device according to a first embodiment of the present invention. As shown in FIG. 1, the water current power generation device 1 of the present embodiment includes a support column 3 extending vertically from an offshore floating station 2, a rotating support column 4, a support column 5, an anchor 6, a mooring cable 7, a rotating body 8, and a rotating body support member 9.

[0018] The station 2 is a facility floating on the sea by buoyancy. Since the support column 5 is connected to an anchor 6 installed on the seabed via a mooring cable 7, the water current power generation device 1 can be positioned at a fixed point without being washed away by the influence of the ocean current. The rotating body 8 receiving the water force of the ocean current generates electricity by rotating. The rotating support column 4 rotates so that the rotating body 8 and the rotating body support member 9 are located on the downstream side of the rotating support column 4 with respect to the direction of the ocean current.

[0019] In this specification, "water current" refers to the flow of water or seawater, and includes not only the direction of laminar flow in which streamlines are aligned in layers, but also a turbulent state in which streamlines are disturbed. "The direction of the water current" refers to the main direction of the entire flow, whether it is laminar flow or turbulent flow. Unless otherwise specified, "upward" refers to the direction from the seabed to above the water surface, and "downward" refers to the direction from above the water surface to the seabed. Also, unless otherwise specified, "front" refers to the upstream direction of the water current, and "rear" refers to the downstream direction of the water current.

[0020] In this specification, a "rotating body" is an object or device that receives the momentum of a water current and converts water current energy into rotational energy. Therefore, it is desirable for the rotating body to be provided with blades that can be changed to rotate by receiving the water current. The blades may be propellers or may have a shape that spirals obliquely with respect to the axial direction of the rotating body.

[0021] The rotating body 8 is a structure capable of converting the energy of the water flow into the rotational energy of the rotating body 8. For example, in the example shown in FIG. 1, the rotating body 8 is installed on the downstream side of the rotating support column 4, and a plurality of blades 10 attached to the rotating body 8 receive the water flow and rotate the rotating body 8. Since it is desirable for the blades 10 to have a shape that allows the rotating body to rotate easily when receiving the water flow, they may be formed in a spiral shape surrounding the body portion of the rotating body.

[0022] By making the length of the rotating body 8 in the axial direction larger than the diameter in the radial direction (at the center of the body portion), it may be configured to be less susceptible to vertical oscillation due to its shape that extends in the downstream direction while rotating by the water flow. In the first embodiment, the diameter of the rotating body 8 in the radial direction is about 10 m, and the length in the axial direction is about 20 m. Also, as the material of the rotating body 8, resins such as fiber-reinforced plastic (FRP) and carbon fiber-reinforced plastic (CFRP), or metals are used. If the rotating body is made of a titanium alloy, it can be used semi-permanently without rusting even in water.

[0023] FIG. 2 is a cross-sectional view of the water current power generation device according to the first embodiment. A rotating support column 4 is rotatably arranged between the support column 3 and the support column 5. The connecting portion between the support column 3 and the rotating support column 4 is arranged such that the convex portion of the support column 3 faces the concave portion of the rotating support column 4 and is in contact with a bearing 16a. The connecting portion between the rotating support column 4 and the support column 5 also has the same configuration as the connecting portion with the support column 3. The rotating support column 4 can freely rotate around the central axis of the support column so that the rotating body 8 can be positioned on the downstream side of the ocean current or facing upstream due to the change in the flow direction of the ocean current. The rotating support column 4 may be configured to be rotatable freely by 360°, but since the power transmission cable will be twisted if the ocean current continues to rotate clockwise or counterclockwise, the rotation angle restriction may be a predetermined angle less than 180° centered on the main direction of the ocean current. Regarding the mechanism for restricting the angle of the rotating support column, it may be configured with a stopper or the like that does not rotate any further after rotating by a certain angle.

[0024] The rotating support column 4 requires a hollow space for accommodating the power transmission cable 21 or the generator 20. The support column 3 or the support column 5 is preferably hollow to ensure a space through which the power transmission cable can extend. When guiding the power transmission cable to the seabed, at least the lower support column 5 is made hollow to pass the power transmission cable downward. On the other hand, when guiding the power transmission cable to an offshore relay point, at least the upper support column 3 may be made hollow.

[0025] The rotating body 8 and the rotating body support member 9 are arranged such that the concave portion 12 inside the rotating body meshes with the convex portion 13 of the rotating body support member 9 and are in contact with the bearings 14a and 14b. The rotating body support member 9 is hollow. The shaft 11 fixed inside the rotating body 8 is accommodated in the hollow space of the rotating body support member 9 and is connected to the generator 20 arranged in the internal space of the rotating support column 4. Therefore, the rotational energy of the rotating body 8 is transmitted to the generator 20 via the shaft 11 to generate electricity. The "shaft for transmitting the rotation of the rotating body to the generator" includes not only the shaft directly connected to the generator but also the shaft that transmits the rotation to the generator via a transmission or the like.

[0026] The rotating body support member 9 is a cylindrical member extending parallel to the rotation axis of the shaft 11, and the shaft 11 penetrates through the inside of the rotating body support member 9. One end of the rotating body support member 9 is fixed to the rotating support column 4, and the other end is arranged to be accommodated inside the rotating body 8. From the outer wall surface of the rotating body support member 9 accommodated inside the rotating body 8, a convex portion 13 protruding radially outward of the axis is formed on the outer periphery of the cylinder. The convex portion 13 is arranged to face the concave portion 12 formed in a groove shape on the inner wall surface of the rotating body 8. Thereby, even when the momentum of the water flow is strong, the rotating body 8 is supported by the convex portion 13 of the rotating body support member 9 fixed to the rotating support column 4, so that the rotating body 8 does not come off from the water current power generation device and is not washed downstream in the direction of the water flow, and moreover, the rotational motion can be maintained. Also, although not shown, the rotating body support member 9 may have a telescopic structure while being fixed to the rotating support column 4. If it has a telescopic structure, the distance between the rotating body 8 and the rotating support column 4 can be adjusted, so that the rotating body 8 can be arranged at an optimal position with less influence of the resistance of the rotating support column 4 on the water flow.

[0027] In this specification, "opposing" means a state in which opposing members are fitted together, but it is not necessarily required that the opposing members are in contact with each other. It also includes a state in which, while being separated from each other, the specific movement of the counterpart member facing each other is restricted. For example, "opposing" includes a structure in which opposing members support each other via oil, bearings, or a combination thereof, etc., even if the convex portion and the concave portion do not directly touch each other.

[0028] A plurality of bearings 14a and 14b may be arranged on the outer periphery of the cylinder of the support member on the front side and the rear side of the convex portion 13. The rear bearing 14b needs to have a strength that can withstand the force with which the water flow tries to wash away the rotating body 8. Due to the presence of the bearings 14a and 14b, the resistance to the rotational movement of the rotating body 8 can be reduced, and it can be rotated at a higher speed. Furthermore, the space formed by the concave portion 12 and the convex portion 13 of the rotating body 8 can be filled with oil, and the rotating body 8 can be rotated smoothly and stably. When filling the concave portion 12 with oil, a known technique may be used as a sealing structure that prevents oil leakage.

[0029] The concave portion 12 and the convex portion 13 are not particularly limited in size or material as long as they have a strength that can withstand the momentum of the water flow received by the rotating body 8 and can stably maintain rotation. Also, if the depth of the concave portion 12 is larger than the height of the convex portion 13, the space between the concave portion 12 and the convex portion 13 can be filled with oil or bearings, so that smooth rotation becomes possible.

[0030] The bearing 14a on the front side of the convex portion 13 and the bearing 14b on the rear side of the convex portion 13 may or may not be of the same size. Since the bearing 14b on the rear side needs to have a strength sufficient to receive the force with which the water flow tries to wash away the rotating body 8 and at the same time needs to maintain rotation, it may be a bearing with a larger diameter than the bearing 14a on the front side. By making the bearing 14b on the rear side larger than the bearing 14a on the front side, the support against the force with which the water flow pushes the rotating body backward can be strengthened. Also, the number of bearings 14b on the rear side of the convex portion 13 may be made larger than the number of bearings 14a on the front side of the convex portion 13 disposed around the rotating body 8. By arranging a larger number of bearings 14b on the rear side of the convex portion 13, the number of contact points between the convex portion 13 and the plurality of bearings 14b increases, so that the support against the force with which the water flow pushes the rotating body backward can be strengthened, and the effect of suppressing the rocking of the rotating body 8 can also be exerted.

[0031] Also, a waterproof mechanism may be provided so that water does not enter the cavity inside the rotating body 8. The waterproof mechanism may be a known waterproof technique. For example, as shown in FIG. 2, an O-ring 15 may be disposed in the gap between the rotating body 8 and the rotating body support member 9 to maintain rotation while preventing water from entering the inside of the rotating body.

[0032] In the example shown in FIG. 2, the rotating body 8 is provided with a concave portion 12 and the rotating body support member 9 is provided with a convex portion 13, but the concave-convex relationship may be reversed. That is, a concave portion may be provided on the rotating body support member 9 side, and a convex portion protruding radially inward from the inner wall surface of the rotating body may face the concave portion of the rotating body support member 9.

[0033] The rotating body of the present embodiment is a downwind type rotating body that rotates on the downstream side of the rotating support column 4. Since the flow velocity of the ocean current decreases or the flow is disturbed due to the resistance of the rotating support column 4, it is desirable to dispose the rotating body 8 at a certain distance from the rotating support column 4. It is desirable to dispose the rotating body at a distance of at least the diameter of the rotating support column or more.

[0034] As described above, the water current power generation device according to the first embodiment can efficiently generate power even in an environment where the direction of the ocean current fluctuates while suppressing the swinging of the rotating body 8. Further, in the water current power generation device according to the first embodiment, since the shaft 11 that rotates integrally with the rotating body 8 is directly connected to the generator in the rotating support column 4, compared with the case where the generator 20 is installed at sea, the rotational energy loss due to a transmission mechanism using gears or the like can be reduced.

[0035] (Second Embodiment) FIG. 3 is a cross-sectional view showing a water current power generation device according to the second embodiment. The second embodiment is different from the first embodiment in that when the rotating body 8 rotates due to the water potential of the ocean current to generate power, the rotating body 8 is located upstream of the rotating support column 4, that is, it is of the upwind type. In the first embodiment, since the rotating body 8 is located downstream of the rotating support column 4, considering the influence that the resistance of the water current by the rotating support column 4 reduces the power generation efficiency, it is necessary to make the length of the rotating body support member 9 long and streamline it. In the second embodiment, since the rotating body 8 is upstream of the rotating support column 4, it is not necessary to lengthen the rotating body support member 9 arranged on the downstream side of the rotating body 8. Also, it is desirable to provide a waterproof mechanism between the rotating body 8 and the rotating body support member 9. In FIG. 3, an O-ring 15 is arranged, but for example, other known waterproof mechanisms such as bellows may also be used.

[0036] The rotating support column 4 rotates so that the rotating body 8 faces the upstream direction when the rotating body 8 receives the water potential of the ocean current. That is, the rotating support column 4 rotates so that the rotating body 8 faces the ocean current. If, for example, the rotating body support member 9 is fixed in a specific direction to a non-rotating support column instead of the rotating support column 4, the rotating body 8 receives the water current from an oblique or lateral direction, so the rotating body 8 does not rotate efficiently and the vibration also increases, resulting in a decrease in power generation efficiency. In this embodiment, since the rotating body 8 can be oriented in the most efficient direction by the rotation of the rotating support column 4, it is possible to generate power efficiently.

[0037] (Third Embodiment) FIG. 4 is a cross-sectional view showing a water current power generation device according to the third embodiment. The third embodiment is different from the first embodiment in that the generator 20 is housed in the internal space of the rotating body support member 9 and a speed changer 30 is interposed between the generator 20 and the shaft 11, but the other configurations are the same as those of the first embodiment. By housing the generator 20 and the speed changer 30 in the internal space of the rotating body support member 9, the length of the shaft 11 can be shortened, and even if the internal space of the rotating support column 4 is small, it will be sufficient.

[0038] (Fourth Embodiment) FIG. 5 is a cross-sectional view showing a water current power generation device according to the fourth embodiment. The fourth embodiment is different from the second embodiment in that the generator 20 is housed in the internal space of the rotating body support member 9 and a speed changer 30 is interposed between the generator 20 and the shaft 11, but the other configurations are the same as those of the second embodiment. By housing the generator 20 and the speed changer 30 in the internal space of the rotating body support member 9, the length of the shaft 11 can be shortened, and even if the internal space of the rotating support column 4 is small, it will be sufficient.

[0039] (Embodiment with Multiple Rotating Bodies Arranged) The water current power generation device according to the first embodiment and the water current power generation device according to the third embodiment are devices in which the rotating body 8 is located on the downstream side of the rotating support column 4 to generate power. A plurality of water current power generation devices according to the first embodiment or the third embodiment can be arranged. For example, in the case shown in FIG. 6, rotating bodies are arranged in series at three positions with different vertical depths. The direction of the ocean current may be different depending on the depth. In such a case, in this example, since each rotating support column 4 can rotate so that the rotating body is positioned in an optimal orientation at each different depth, the overall power generation efficiency will be improved compared to a system in which the rotating body is fixed in a specific direction.

[0040] The water current power generation device according to the second embodiment and the water current power generation device according to the fourth embodiment are devices in which the rotating body 8 is located upstream of the rotating support column 4 to generate power. A plurality of water current power generation devices according to the second embodiment or the fourth embodiment can be arranged. For example, in the case shown in FIG. 7, the rotating bodies are arranged in series at three positions with different depths in the vertical direction. The direction of the ocean current may vary depending on the depth. In such a case, in this example, since each rotating support column 4 can rotate so that the rotating body is positioned in an optimal orientation at each different depth, the overall power generation efficiency is improved compared to a system in which the rotating body is fixed in a specific direction.

[0041] In the water current power generation device according to the third embodiment, the generator 20 was housed inside the rotating body support member 9. Here, the rotating body support member is not limited to a member composed only of a member that linearly extends in the direction from the rotating body toward the rotating support column 4 as shown in FIG. 4. For example, FIG. 8 is a diagram showing a case where a plurality of water current power generation devices according to the third embodiment are arranged. In this example, the rotating body support member 9 is formed by connecting members 9a, 9b, and 9c. Although not shown, since each of the members 9a, 9b, and 9c has a hollow space inside, the power transmission cable connected to the generator can reach the inside of the support column via the hollow space of the rotating body support member 9.

[0042] FIG. 9 is a diagram showing another case where a plurality of water current power generation devices according to the third embodiment are arranged. In this example, it is a case where three rotating bodies are arranged on a horizontal plane at the same depth. The generators are arranged inside each rotating body support member. When arranging the generators inside the rotating support column 4, it is necessary to arrange three generators in the internal space of the rotating support column 4 or a complicated transmission mechanism for transmitting the rotation of each rotating body to the rotating support column 4 is required. In this example, the generators are arranged inside each rotating body support member, and the power transmission cables from each generator can reach the inside of the rotating support column 4 via the inside of each rotating body support member, and there is no shortage of space inside the support column.

[0043] FIG. 10 is a diagram showing a case where the water flow power generation devices according to the third and fourth embodiments are combined. When the rotating bodies are arranged in the front and rear at the same depth, the rear rotating body is affected by the change in the water flow caused by the front rotating body. Therefore, it is desirable to make the distance between the front and rear rotating bodies as long as possible.

[0044] In the embodiments of this specification, the description has been made as a power generation device by ocean currents in the sea. However, the present invention is not limited to ocean currents and includes power generation devices in places with flowing water such as rivers and lakes.

Description of Reference Numerals

[0045] 1... Water flow power generation device, 2... Station, 3... Support column, 4... Rotating support column, 5... Support column, 6... Anchor, 7... Mooring cable, 8... Rotating body, 9... Rotating body support member, 10... Blade, 11... Shaft, 12... Recess, 13... Protrusion, 14a, 14b... Bearing, 15... O-ring, 16a, 16b... Bearing, 20... Generator, 21... Power transmission cable, 30... Transmission

Claims

Claim 1 a hollow column; a hollow rotary column connected to the column and rotatable; a rotating body rotated by water flow; a rotating body support member having one end fixed to the rotary column and supporting the rotating body; a shaft fixed to the rotating body and rotating integrally with the rotating body, and comprising: the shaft passes through the internal space of the rotating body support member and is connected to a generator; the rotating body support member has a cylindrical body extending in the direction of the rotation axis of the rotating body; the rotating body is rotatably supported by a convex portion protruding radially outward from the rotating body support member and a concave portion inside the rotating body facing each other; A water flow power generation device characterized by the above. Claim 2 The power transmission cable connected to the generator is laid in the internal space of the rotating body support member or the column, and the water flow power generation device according to claim 1, characterized in that. Claim 3 The water flow power generation device according to claim 1, characterized in that the range of the rotatable angle of the rotary column is less than 180 degrees.

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