Tidal power generator and tidal power generation method

Abstract

To provide a tidal power generator and a tidal power generation method which enable power generation using tidal current, in particular, a tidal power generator and a tidal power generation method which can continue efficient power generation even if a direction of the tidal current changes in a sea area in which the direction of the tidal current changes over time.SOLUTION: A tidal power generator generates electric power by using tidal current and includes: a first opening and a second opening configured to introduce the tidal current into the tidal power generator; a rotating body which is rotated by the tidal current when the tidal current is introduced into the tidal power generator through the first opening or the second opening; a first opening / closing door and a second opening / closing door which are respectively provided at the first opening and the second opening and open or close parts of the first opening and the second opening by the tidal current when the dital current is introduced into the tidal power generator; and a power generator which converts rotation of the rotating body into electricity. A tidal power generation method which utilizes the tidal power generator is also provided.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a tidal power generation device and a tidal power generation method.

Background Art

[0002] Conventionally, hydroelectric power generation has been used, which generates electric power by rotating a waterwheel using the water flow of rivers or the like. In general hydroelectric power generation, since water flow is generated using water stored in a dam or the like, there are significant limitations in terms of installation location and water volume.

[0003] On the other hand, ocean tides occur, and the ocean occupies more than 70% of the Earth's surface area. If power generation can be carried out using tides, power generation can be achieved over a wider range. However, as shown in Non-Patent Document 1, tidal power generation has not yet been put into practical use due to problems such as cost.

[0004] The direction of the tidal current varies with time. For example, as shown in Non-Patent Document 2, in the Kanmon Strait, the eastward tidal current (east flow) and the westward tidal current (west flow) alternate repeatedly. In order to efficiently generate power using tidal currents, it is important to cope with such variations in the direction of tidal currents.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention provides a tidal current power generation device and a tidal current power generation method that enable power generation using tidal currents. In particular, in a sea area where the direction of the tidal current fluctuates over time, the present invention provides a tidal current power generation device and a tidal current power generation method that can efficiently continue power generation even when the direction of the tidal current fluctuates.

Means for Solving the Problems

[0007] The present invention is a tidal current power generation device that generates electric power using tidal currents, comprising: a first opening that opens on one side of the tidal current power generation device and introduces the tidal current into the tidal current power generation device; a second opening that opens on the other side of the tidal current power generation device and introduces the tidal current into the tidal current power generation device; a rotating body that rotates by the tidal current when the tidal current is introduced into the tidal current power generation device from the first opening or the second opening; a first opening and closing door provided at the first opening that closes a part of the first opening by the tidal current when the tidal current is introduced into the tidal current power generation device from the first opening and opens the first opening by the tidal current when the tidal current is introduced into the tidal current power generation device from the second opening; a second opening and closing door provided at the second opening that closes a part of the second opening by the tidal current when the tidal current is introduced into the tidal current power generation device from the second opening and opens the second opening by the tidal current when the tidal current is introduced into the tidal current power generation device from the first opening; and a generator that converts the rotation of the rotating body into electricity. In the tidal current power generation device configured as described above, due to the change in the direction of the tidal current, there are time zones when the tidal current flows into the tidal current power generation device from the first opening provided on one side and time zones when the tidal current flows into the tidal current power generation device from the second opening provided on the other side. When the tidal current flows into the tidal current power generation device from the first opening, the tidal current closes a part of the first opening and opens the second opening. On the other hand, when the tidal current flows into the tidal current power generation device from the second opening, the tidal current closes a part of the second opening and opens the first opening. By closing a part of the opening on the introduction side, the tidal current is made to act on the rotating body, and by opening the opening on the discharge side, the tidal current is discharged. The rotating body is rotated by the tidal current introduced into the tidal current power generation device, and the rotational motion of the rotating body is converted into electrical energy by the generator.

[0008] In the above configuration, the first opening and the second opening may be configured to open in opposite directions to each other. In the tidal current power generation device configured as described above, in a sea area where the direction of the tidal current changes in the opposite direction over time, the tidal current is efficiently made to flow into the tidal current power generation device from the first opening and the second opening.

[0009] In the above configuration, the first opening / closing door is configured to be rotatable about a first rotation axis and is configured to be rotated by the tidal current when the tidal current is introduced into the tidal current power generation device from the first opening and the rotation is stopped by a first stopper, thereby closing a part of the first opening. The second opening / closing door is configured to be rotatable about a second rotation axis and is configured to be rotated by the tidal current when the tidal current is introduced into the tidal current power generation device from the second opening and the rotation is stopped by a second stopper, thereby closing a part of the second opening. In the tidal current power generation device configured as described above, the opening / closing door provided at the opening on the side where the tidal current is introduced is rotated by the tidal current and the rotation is stopped at a predetermined position by a stopper, thereby closing a part of the opening.

[0010] In the above configuration, the first opening / closing door is configured to be rotatable about a first rotation axis, and a rotation limiting mechanism is provided on the first rotation axis to limit the rotation of the first opening / closing door so as not to rotate it to a position parallel to the tidal current. The second opening / closing door is configured to be rotatable about a second rotation axis, and a rotation limiting mechanism is provided on the second rotation axis to limit the rotation of the second opening / closing door so as not to rotate it to a position parallel to the tidal current. Such a configuration may also be adopted. In the tidal current power generation device configured as described above, when introducing the tidal current, the rotation door receives the tidal current and rotates, thereby closing a part of the opening.

[0011] In the above configuration, the first opening / closing door has a first surface arranged in a direction to receive the tidal current when the tidal current is introduced into the tidal current power generation device from the first opening, and a second surface arranged in a direction to receive the tidal current when the tidal current is introduced into the tidal current power generation device from the second opening. The second opening / closing door has a third surface arranged in a direction to receive the tidal current when the tidal current is introduced into the tidal current power generation device from the first opening, and a fourth surface arranged in a direction to receive the tidal current when the tidal current is introduced into the tidal current power generation device from the second opening. Such a configuration may also be adopted. In the tidal current power generation device configured as described above, the surfaces of each opening / closing door that receive the tidal current are configured to be different when introducing the tidal current from each opening / closing door and when discharging the tidal current.

[0012] In the above configuration, the rotating body has rotating blades that rotate upon receiving the tidal current, and the rotating blades may be configured to include a fixed portion fixed to a rotation axis and a rotating portion configured to be rotatable relative to the fixed portion. In the tidal current power generation device configured as described above, the rotating blades of the rotating body are composed of a fixed portion and a rotating portion. The entire rotating blade rotates about the rotation axis due to the tidal current, and the rotating portion is configured to rotate relative to the fixed portion.

[0013] In the above configuration, it may further include a floating body for floating the rotating body in the sea, and may be configured such that the rotating body is floated below the water surface by the buoyancy of the floating body. In the tidal power generation device configured as described above, the tidal current is made to act on the rotating body by adjusting the buoyancy of the floating body to float the rotating body below the water surface.

[0014] In the above configuration, a plurality of the rotating bodies may be arranged, the first opening and the second opening may be provided for each of the rotating bodies, the direction in which the first opening opens may be the same among the plurality of rotating bodies, and the direction in which the second opening opens may be the same among the plurality of rotating bodies. In the tidal power generation device configured as described above, a plurality of rotating bodies are arranged with the directions in which the first opening and the second opening open being the same.

[0015] It is also possible to implement the above tidal power generation device as a tidal power generation method.

Advantages of the Invention

[0016] According to the present invention, it is possible to provide a tidal power generation device and a tidal power generation method that can realistically achieve power generation using tidal currents. In particular, in a sea area where the direction of the tidal current varies with time, power generation can be efficiently continued even when the direction of the tidal current changes.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Best Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings shown as an example. FIG. 1 is a side view (cross-sectional view) of the tidal current power generation device 1. FIG. 2 is a plan view of the tidal current power generation device 1 of the present invention. The tidal current power generation device 1 is installed in the ocean where tidal currents (ocean currents) occur. FIGS. 1 and 2 show an example in which two tidal current power generation devices 1 are installed on a barge 2 floating in the ocean. Also, in FIG. 1, the shaded area represents seawater. Since the configurations of the two tidal current power generation devices 1 are the same, the reference numerals in the drawings are shown only for one tidal current power generation device 1, and the reference numerals for the other tidal current power generation device 1 are omitted.

[0019] As shown in FIGS. 1 and 2, the tidal current power generation device 1 mainly includes an opening 10 (the first opening 11 and the second opening 12) for introducing tidal current (seawater) into the tidal current power generation device 1 and discharging tidal current (seawater) from the tidal current power generation device 1, a rotating body 20 that rotates by the tidal current when the tidal current is introduced into the tidal current power generation device 1 from the opening 10, a shielding wall 30 that shields the side surface of the rotating body 20, an opening / closing door 40 (the first opening / closing door 41 and the second opening / closing door 42) provided in the opening 10 for opening and closing a part of the opening 10, a generator 50 that converts the rotation of the rotating body 20 into electricity, a crane 60 for lifting the tidal current power generation device 1 during maintenance, and the like.

[0020] The barge 2 is formed of a material that can float in seawater. The lower part of the barge 2 is arranged to sink into the water, and the upper part of the barge 2 is arranged to be exposed above the sea. The bottom surface of the barge 2 is connected to the seabed by a connecting means such as a rope 3, and the barge 2 is maintained so as not to move upward when it is at a certain height or more above the seabed. A plurality of underwater spaces 4 for accommodating the tidal current power generation device 1 are formed in the underwater part of the barge 2. The part of the barge 2 above the sea is surrounded by side walls and a ceiling to form an above-sea space 5. Inside the above-sea space 5, the generator 50, the crane 60, and the like are arranged.

[0021] As shown in Fig. 1, the rotating body 20 is accommodated in the sea space 4 of the base ship 2, and the surrounding of the rotating body 20 is filled with seawater. The rotating body 20 is fixed above the floating body 21 and is installed rotatably together with the floating body 21. The rotating body 20 is configured to float in the ocean by the buoyancy of the floating body 21. By balancing the buoyancy of the floating body 21 and the weight of the rotating body 20, the rotating body 20 is made to float below the water surface. More specifically, the buoyancy of the floating body 21 is adjusted so that the upper surface of the rotating body 20 is located slightly below the water surface. That is, while the rotating body 20 floats in the ocean, the entire rotating body 20 is arranged in the sea. Also, the shielding wall 30 and the opening / closing door 40 are arranged above the floating body 21 and float below the water surface in the same manner as the rotating body 20. Above the floating body 21, a bearing 6 is provided to prevent the rotation shaft 22 of the rotating body 20, which will be described later, from moving.

[0022] As shown in Fig. 2, shielding walls 30 are arranged outside the left and right ends in the width direction of the rotating body 20. An opening 10 forms a space that is sandwiched between the two shielding walls 30 and does not block seawater in the horizontal direction (width direction) and the vertical direction (height direction) in the sea. The shape of the opening 10 can be said to be rectangular. The opening 10 is composed of a first opening 11 and a second opening 12. In a top view, the first opening 11 opens to one side of the tidal power generation device 1, while the second opening 12 opens to the other side of the tidal power generation device 1. More specifically, the first opening 11 and the second opening 12 open in opposite directions. In other words, the direction in which the first opening 11 opens and the direction in which the second opening 12 opens are 180° different. For example, the tidal power generation device 1 is arranged such that the first opening 11 on one side faces east and the second opening 12 on the other side faces west. When a tidal current is generated from one side to the other side, the tidal current is introduced into the tidal power generation device 1 from the first opening 11, and the tidal current is discharged to the outside from the second opening 12. When a tidal current is generated from the other side to one side, the tidal current is introduced into the tidal power generation device 1 from the second opening 12, and the tidal current is discharged to the outside from the first opening 11. The first opening 11 and the second opening 12 function as inlets for introducing the tidal current from the outside into the tidal power generation device 1 and also function as outlets for discharging the tidal current from the tidal power generation device 1 to the outside. When the first opening 11 functions as an inlet, the second opening 12 functions as an outlet, and when the second opening 12 functions as an inlet, the first opening 11 functions as an outlet.

[0023] Each shielding wall 30 is formed in a flat plate shape that forms surfaces in the horizontal and vertical directions. Further, each shielding wall 30 is formed by connecting two plates so as to be bent at a connecting portion 31 near the center in the front-rear direction (the direction of the tidal current). The connecting portion 31 of each shielding wall 30 is arranged near the center in the front-rear direction of the rotating body 20, and each shielding wall 30 is bent and arranged so that the distance in the left-right direction (width direction) between the shielding walls 30 is minimized at the connecting portion 31. The shielding walls 30 are arranged so that the distance between the shielding walls 30 widens toward the first opening 11 side and the second opening 12 side. That is, the shielding walls 30 are arranged so that the flow path of the tidal current gradually narrows from the first opening 11 or the second opening 12 toward the connecting portion 31 near the center of the rotating body 20. When two tidal current power generation devices 1 are arranged side by side, the ends of the shielding walls 30 are connected to each other on each of the first opening 11 side and the second opening 12 side. The shielding wall 30 with both ends connected has a rhombus shape in a top view. Thereby, it is possible to prevent the tidal current from flowing in from the front or the rear between the shielding walls 30.

[0024] The first opening 11 is provided with a first opening / closing door 41, and the second opening 12 is provided with a second opening / closing door 42. The first opening / closing door 41 is configured to be rotatable about a first rotation axis 43 disposed vertically near the center in the width direction of the rotating body 20. The rotation region of the first opening / closing door 41 is between the position where the rotation of the first opening / closing door 41 shown by the solid line in FIG. 2 is stopped by the first stopper 45 and the position where it is substantially parallel to the tidal current shown by the broken line in FIG. 2 (the region shown by the arc-shaped arrow in FIG. 2). However, in the state shown by the broken line in FIG. 2, the first opening / closing door 41 does not rotate up to the position parallel to the tidal current and is restricted to rotate only up to a little before the parallel position. A rotation restricting mechanism (not shown) is provided on the first rotation axis 43 so as to restrict the rotation of the first opening / closing door 41 from rotating up to the position parallel to the tidal current. The second opening / closing door 42 is configured to be rotatable about a second rotation axis 44 disposed vertically near the center in the width direction of the rotating body 20. The rotation region of the second opening / closing door 42 is between the position where the rotation of the first opening / closing door 42 shown by the solid line in FIG. 2 is stopped by the second stopper 46 and the position where it is substantially parallel to the tidal current shown by the broken line in FIG. 2 (the region shown by the arc-shaped arrow in FIG. 2). However, in the state shown by the broken line in FIG. 2, the second opening / closing door 42 does not rotate up to the position parallel to the tidal current and is restricted to rotate only up to a little before the parallel position. A rotation restricting mechanism (not shown) is provided on the second rotation axis 44 so as to restrict the rotation of the second opening / closing door 42 from rotating up to the position parallel to the tidal current.

[0025] FIG. 3 is an enlarged plan view of the rotating body 20. As shown in FIG. 3, the rotating body 20 as a whole has a circular shape in plan view. The rotating body 20 has a rotating shaft 22 and a plurality of rotating blades 23 radially extending from the rotating shaft 22. The rotating shaft 22 is arranged in the vertical direction and is arranged such that the rotating body 20 rotates in the horizontal direction. Each rotating blade 23 has a fixed portion 23A fixed to the rotating shaft 22 and a rotating portion 23C connected to the fixed portion 23A via a rotating shaft 23B. Both the fixed portion 23A and the rotating portion 23C are formed in a flat plate shape that forms planes in the horizontal and vertical directions. The rotating portion 23C is configured to be rotatable about the rotating shaft 23B with respect to the fixed portion 23A. When a tidal current is introduced into the tidal current power generation device 1 from the first opening 11 or the second opening 12, the rotating blade 23 rotates about the rotating shaft 22 by receiving the tidal current. While the entire rotating blade 23 (the fixed portion 23A and the rotating portion 23C) rotates about the rotating shaft 22, the rotating portion 23C rotates back and forth about the rotating shaft 23B with respect to the fixed portion 23A according to the increase and decrease of the tidal current speed. The direction in which the entire rotating blade 23 rotates about the rotating shaft 22 is the same when a tidal current is introduced into the tidal current power generation device 1 from the first opening 11 and when a tidal current is introduced into the tidal current power generation device 1 from the second opening 12 (clockwise in FIG. 3). A stopper 24 is formed on the outer peripheral portion of the rotating blade 23 to restrict the rotating portion 23C from rotating more than a certain angle with respect to the fixed portion 23A. As shown in FIG. 1, four rotating blades 23 are arranged side by side in the vertical direction and are configured to rotate coaxially about the rotating shaft 22.

[0026] As shown in FIG. 1, a generator 50 is connected to the upper end of the rotating shaft 22. The generator 50 has a gear 51 that rotates coaxially with the rotating shaft 22 of the rotating body 20, a speed increasing mechanism 52 that increases the rotational motion of the gear 51, a power generation mechanism 53 that converts the increased rotational motion into electrical energy, a control panel 54 for controlling the power generation mechanism 53, and the like. Each mechanism constituting the above-described generator 50 is housed inside the marine space 5. The functions of the gear 51, the speed increasing mechanism 52, the power generation mechanism 53, and the control panel 54 are the same as those of a general generator, so detailed inventions of these functions are omitted.

[0027] FIG. 4 shows a state in which a tidal current is introduced into the tidal current power generation device 1 from the first opening 11, and FIG. 5 shows a state in which a tidal current is introduced into the tidal current power generation device 1 from the second opening 12. The operation of the tidal current power generation device 1 will be described with reference to FIGS. 4 and 5. In the following description, the surface that receives the tidal current when the first door 41 rotates counterclockwise is the first surface 41A, the surface that receives the tidal current when it rotates clockwise is the second surface 41B, the surface that receives the tidal current when the second door 42 rotates counterclockwise is the third surface 42A, and the surface that receives the tidal current when it rotates clockwise is the fourth surface 42B. The first surface 41A and the fourth surface 42B are surfaces arranged in a direction to receive the tidal current when the tidal current is introduced into the tidal current power generation device 1 from the first opening 11, and the second surface 41B and the third surface 42A are surfaces to receive the tidal current when the tidal current is introduced into the tidal current power generation device 1 from the second opening 12.

[0028] When a tidal current is introduced into the tidal current power generation device 1 from the first opening 11, as shown in FIG. 4, the first surface 41A of the first opening / closing door 41 receives the tidal current and rotates counterclockwise. The rotated first opening / closing door 41 is stopped from rotating by the first stopper 45. As a result, the first opening / closing door 41 closes a part of the first opening 11 (the left half in FIG. 4). That is, the opening area of the first opening 11 is decreased. At this time, the fourth surface 42B of the second opening / closing door 42 receives the tidal current discharged from the tidal current power generation device 1 to the outside and rotates clockwise. The rotated second rotating door 42 is maintained in a rotated state by the tidal current until it reaches a position substantially parallel to the tidal current (closer to the second stopper 46 than the parallel position). As a result, the second opening / closing door 42 opens without closing the second opening 12. With a part of the first opening 11 closed and the second opening 12 open, a tidal current is introduced into the tidal current power generation device 1 from the first opening 11. The introduced tidal current causes the rotating body 20 to rotate clockwise. The rotation of the rotating body 20 is converted into electricity by the generator 50. The tidal current that has entered the tidal current power generation device 1 is discharged from the second opening 12 to the outside of the tidal current power generation device 1.

[0029] When a tidal current is introduced into the tidal current power generation device 1 from the second opening 12, as shown in FIG. 5, the third surface 42A of the second opening / closing door 42 receives the tidal current and rotates counterclockwise. The rotated second opening / closing door 42 is stopped from rotating by the second stopper 46. As a result, the second opening / closing door 42 closes a part of the second opening 12 (the right half in FIG. 5). That is, the opening area of the second opening 12 is reduced. At this time, the second surface 41B of the first opening / closing door 41 receives the tidal current discharged from the tidal current power generation device 1 to the outside and rotates clockwise. The rotated first rotating door 41 is maintained in the rotated state by the tidal current until it reaches a position substantially parallel to the tidal current (closer to the first stopper 45 than the parallel position). As a result, the first opening / closing door 41 opens the first opening 11 without closing it. With a part of the second opening 12 closed and the first opening 11 open, a tidal current is introduced into the tidal current power generation device 1 from the second opening 12. The introduced tidal current causes the rotating body 20 to rotate clockwise. The rotation of the rotating body 20 is converted into electricity by the generator 50. The tidal current that has entered the tidal current power generation device 1 is discharged from the first opening 11 to the outside of the tidal current power generation device 1.

[0030] In the tidal current power generation device 1 configured as described above, by providing the first opening 11 that opens on one side of the tidal current power generation device 1 and the second opening 12 that opens on the other side, when the direction of the tidal current changes, it is possible to automatically switch the opening through which the tidal current is introduced according to the direction of the tidal current and introduce the tidal current into the tidal current power generation device 1 without changing the direction of the tidal current power generation device 1 or the direction of the opening. If the first opening 11 and the second opening 12 are arranged so as to be in opposite directions to each other, it is possible to efficiently introduce the tidal current into the tidal current power generation device 1 in a sea area where the direction of the tidal current changes by 180° over time.

[0031] By providing a first opening / closing door 41 for the first opening 11 and a second opening / closing door 42 for the second opening 12, the first opening / closing door 41 and the second opening / closing door 42 are opened and closed by the tidal current. When introducing the tidal current into the tidal current power generation device 1 from the first opening 11, the first opening / closing door 41 closes a part of the first opening 11 by the tidal current, while the second opening / closing door 42 opens the second opening 12 by the tidal current. Conversely, when introducing the tidal current into the tidal current power generation device 1 from the second opening 12, the second opening / closing door 42 closes a part of the second opening 12 by the tidal current, while the first opening / closing door 41 opens the first opening 11 by the tidal current. That is, a part of the opening on the side where the tidal current is introduced is closed, and the opening on the side where the tidal current is discharged is opened. Thereby, the flow path of the tidal current can be narrowed on the introduction side and efficiently applied to the rotating body 20, and the tidal current can be discharged to the maximum extent on the discharge side. The rotation of the opening / closing door on the introduction side is restricted by a stopper, while the rotation of the opening / closing door on the discharge side is naturally positioned by the rotation of the rotary door to a position substantially parallel to the tidal current. By adopting such a configuration, the opening / closing door can be automatically opened and closed depending only on the change in the direction of the tidal current without using an electric control mechanism or the like. If the opening / closing door is configured to be rotatable to a position parallel to the tidal current, there is a possibility that the opening / closing door will not rotate reliably when introducing the tidal current. Therefore, a rotation restricting mechanism is provided to restrict the rotation of the opening / closing door so that it does not rotate to a position parallel to the tidal current.

[0032] The rotating blades 23 of the rotating body 20 are configured to include a fixed portion 23A fixed to the rotating shaft 22 and a rotating portion 23C configured to be rotatable about a rotating shaft 23B with respect to the fixed portion 23A. If the entire rotating blade is fixed to the rotating shaft, the resistance caused by a slight fluctuation of the tidal current directly acts on the rotating shaft 22. By configuring the rotating portion 23C to be rotatable back and forth with respect to the fixed portion 23A, a part of the resistance acting on the rotating shaft 22 described above can be escaped. That is, the load acting on the rotating shaft 22 can be reduced. Further, the rotating body 20 is disposed above the floating body 21. By adjusting the buoyancy of the floating body 21 so that the rotating body 20 floats below the water surface, the tidal current can be efficiently applied to the entire rotating body 20.

[0033] The output obtained by the tidal current power generation device of the present invention is roughly calculated. Consider the force ΔF applied to a minute width dr [m] at a position r [m] in the radial direction from the center of the rotation axis of the rotating body. Since the force ΔF is generated by the weight of seawater acting on the rotating body, assuming the height of the rotating body is H [m], the density of seawater is ρ [kg / m 3 , the velocity of the tidal current is V [m / s], and the gravitational acceleration is g [m / s 2 , the force ΔF can be expressed by the following formula (1). ΔF = ρ × H × dr × V × g (1) Here, first, find the rotational speed n [rpm] of the rotating body. Assuming the velocity of the tidal current V is 2 m / s, the radius r of the rotating body is 2 m, and the pi π is 3.14, the rotational speed n can be calculated by the following formula (2). n = V × 60 / (2 × π × r) = 2 × 60 / (2 × 3.14 × 2) ≒ 9.55 (2) Find the work L given by the tidal current to the rotating body per minute at a position r [m] in the radial direction from the center of the rotation axis of the rotating body. Assuming the circumferential movement distance of the rotating body is D [m], the work ΔL given by the tidal current to the rotating body in the minute width dr can be expressed by the following formula (3) using the force F and the movement distance D. Here, the circumferential movement distance D at a position r [m] in the radial direction can be expressed as 2 × π × r × n using the rotational speed n. ΔL = ΔF × D = ρ × H × dr × V × g × 2 × π × r × n (3) Assuming the radius of the rotating body is 2 m, the total work L given by the tidal current to the rotating body in the region from the center of the rotation axis to the outer peripheral part can be expressed by the following formula (4).

Equation

[0034] Fig. 6 is a plan view showing an example of arranging a large number of tidal current power generation devices 1. In this embodiment, an example is shown in which five pontoons 2 are arranged in parallel and a total of 64 tidal current power generation devices 1 are arranged in four rows between the pontoons 2. Each tidal current power generation device 1 has the same configuration as that of the above-described embodiment. When arranging the tidal current power generation devices 1, the direction in which the first opening opens is the same among the plurality of tidal current power generation devices 1, and the direction in which the second opening opens is the same among the plurality of tidal current power generation devices 1. That is, when the tidal current flows in a certain direction, the tidal current is simultaneously introduced into the plurality of tidal current power generation devices 1 from the first opening 11 or the second opening 12. In this way, by arranging a large number of tidal current power generation devices 1 side by side, the electric energy that can be generated can be increased.

[0035] The number of the tidal current power generation devices 1, the size of the rotating body 20, etc. described in the above embodiment are merely examples. The specifications of the tidal current power generation device 1 may be optimally set in consideration of various conditions such as the location where the tidal current power generation device 1 is installed and the amount of electric energy to be generated. It is not essential to use the pontoon 2 for arranging the tidal current power generation device 1.

[0036] In the above embodiment, a configuration in which the direction in which the first opening 11 opens and the direction in which the second opening 12 opens are different by 180° is shown, but the present invention is not necessarily limited to this configuration. It is possible to optimally adjust the angle of the opening in consideration of the temporal change in the direction of the tidal current in the sea area where the tidal current power generation device is installed.

[0037] In the above-described embodiment, when introducing the tidal current from the first opening 11, the first door 41 rotates counterclockwise, and when introducing the tidal current from the second opening 12, the second door 42 rotates counterclockwise. However, the rotation direction of the door is not limited to this. When introducing the tidal current from the first opening 11, the first door 41 may rotate clockwise, and when introducing the tidal current from the second opening 12, the second door 42 may rotate clockwise. Also, the rotation directions when introducing the tidal current may be opposite between the first door 41 and the second door 42. The rotation direction of the rotating body 20 is not limited to counterclockwise either, and it may be configured to rotate clockwise.

[0038] In the above-described embodiment, the rotation of the opening / closing door on the introduction side is restricted by a stopper, and the rotation of the opening / closing door on the discharge side is naturally positioned by the tidal current. However, the present invention is not necessarily limited to this configuration. For example, it is also possible to configure the rotation of the opening / closing door on the introduction side to be naturally positioned by the tidal current, or to configure the rotation of the opening / closing door on the discharge side to be restricted by a stopper. Also, the stopper may be provided on the rotation axis of the opening / closing door. A mechanism that restricts the rotation of the opening / closing door at a predetermined rotation angle is called a stopper.

[0039] In the above-described embodiment, a configuration in which the first opening is closed by about half by the opening / closing door on the introduction side is shown. However, the range for closing the opening is not necessarily limited to this. A configuration that closes at least a part of the opening is included in the present invention. Also, when discharging the tidal current, a configuration in which the first opening 11 and the opening are opened by the opening / closing door is shown. However, opening the opening does not necessarily mean that the opening / closing door completely blocks the tidal current. There is a possibility that the opening / closing door may move slightly left and right due to a slight fluctuation in the tidal current, and thereby the tidal current may be slightly blocked. Even in such a case, if the opening / closing door is arranged substantially parallel to the tidal current, it can be said that the opening is in an open state.

[0040] In the above embodiment, an example in which the rotary blade 23 is composed of a fixed portion 23A and a rotating portion 23C was shown, but the present invention is not necessarily limited to this configuration. It is also possible to adopt a rotary blade that rotates integrally about the rotation axis 22 without providing a rotating portion. Further, the shape of the rotary blade is not limited to a flat plate shape. Naturally, it is also possible to use a rotary blade having a curved surface, and various impellers used in conventional water wheels for hydraulic power generation and the like can be used as the rotary blade of the present invention.

[0041] In the above embodiment, the configuration of the generator 50 is merely illustrative. It is possible to add various conventionally known configurations to the generator in order to efficiently convert rotational motion into electrical energy.

[0042] Needless to say, the present invention is not limited to the above embodiment. As is obvious to those skilled in the art, · Appropriately changing the combination of mutually replaceable members, configurations, etc. disclosed in the above embodiment and applying them · Although not disclosed in the above embodiment, appropriately replacing members and configurations, etc. that are known technologies and mutually replaceable with the members and configurations, etc. disclosed in the above embodiment, and also changing their combination and applying them · Although not disclosed in the above embodiment, appropriately replacing members and configurations, etc. that can be assumed by those skilled in the art as substitutes for the members and configurations, etc. disclosed in the above embodiment based on known technologies, etc., and also changing their combination and applying them are disclosed as one embodiment of the present invention.

Explanation of Reference Numerals

[0043] 1... Tidal power generation device, 2... Barge, 3... Rope, 4... Submarine space, 5... Maritime space, 6... Bearing, 10... Opening, 11... First opening, 12... Second opening, 20... Rotating body, 21... Floating body, 22... Rotation axis, 23... Rotor blade, 24... Stopper, 30... Shielding wall, 31... Connecting part, 40... Opening / closing door, 41... First opening / closing door, 42... Second opening / closing door, 43... First rotation axis, 44... Second rotation axis, 45... First stopper, 46... Second stopper, 50... Generator, 51... Gear, 52... Speed increasing mechanism, 53... Power generation mechanism, 54... Control panel, 60... Crane.

Claims

1. A tidal current power generation device that generates electric power using tidal currents, comprising: a first opening that opens on one side of the tidal current power generation device and introduces the tidal current into the tidal current power generation device; a second opening that opens on the other side of the tidal current power generation device and introduces the tidal current into the tidal current power generation device; a rotating body that rotates by the tidal current when the tidal current is introduced into the tidal current power generation device from the first opening or the second opening; a first opening / closing door provided at the first opening, which closes a part of the first opening by the tidal current when the tidal current is introduced into the tidal current power generation device from the first opening, and opens the first opening by the tidal current when the tidal current is introduced into the tidal current power generation device from the second opening; a second opening / closing door provided at the second opening, which closes a part of the second opening by the tidal current when the tidal current is introduced into the tidal current power generation device from the second opening, and opens the second opening by the tidal current when the tidal current is introduced into the tidal current power generation device from the first opening; a generator that converts the rotation of the rotating body into electricity.

2. The tidal current power generation device according to claim 1, wherein the first opening and the second opening open in opposite directions.

3. The first opening / closing door is configured to be rotatable about a first rotation axis, and is configured to close a part of the first opening by rotating by the tidal current and being stopped by a first stopper when the tidal current is introduced into the tidal current power generation device from the first opening. The second opening / closing door is configured to be rotatable about a second rotation axis, and is configured to close a part of the second opening by rotating by the tidal current and being stopped by a second stopper when the tidal current is introduced into the tidal current power generation device from the second opening.

4. The first opening / closing door is configured to be rotatable about a first rotation axis. A rotation limiting mechanism is provided on the first rotation axis to limit the rotation of the first opening / closing door so that it does not rotate to a position parallel to the tidal current. The second opening / closing door is configured to be rotatable about a second rotation axis. The tidal power generation device according to claim 1, wherein a rotation limiting mechanism for limiting the rotation of the second opening / closing door so as not to rotate to a position parallel to the tidal current is provided on the second rotation shaft.

5. The first opening / closing door has a first surface arranged in a direction to receive the tidal current when the tidal current is introduced into the tidal power generation device from the first opening, and a second surface arranged in a direction to receive the tidal current when the tidal current is introduced into the tidal power generation device from the second opening. The tidal power generation device according to claim 1, wherein the second opening / closing door has a third surface arranged in a direction to receive the tidal current when the tidal current is introduced into the tidal power generation device from the first opening, and a fourth surface arranged in a direction to receive the tidal current when the tidal current is introduced into the tidal power generation device from the second opening.

6. The rotating body has rotating blades that rotate by receiving the tidal current. The tidal power generation device according to claim 1, wherein the rotating blade includes a fixed portion fixed to a rotation shaft and a rotating portion configured to be rotatable with respect to the fixed portion.

7. The tidal power generation device further includes a floating body for floating the rotating body in the sea. The tidal power generation device according to claim 1, wherein the rotating body is configured to float below the water surface by the buoyancy of the floating body.

8. A plurality of the tidal power generation devices are arranged. The first opening and the second opening are provided for each rotating body. The direction in which the first opening opens is the same among the plurality of tidal power generation devices. The tidal power generation device according to claim 1, wherein the direction in which the second opening opens is the same among the plurality of tidal power generation devices.

9. A tidal power generation device that generates electric power using tidal current, comprising: a step of introducing the tidal current into the tidal power generation device from the first opening in a state where a part of the first opening is closed by a first opening / closing door provided at the first opening and a second opening / closing door provided at the second opening is opened when the tidal current is introduced into the tidal power generation device from the first opening; a step of introducing the tidal current into the tidal power generation device from the second opening in a state where a part of the second opening is closed by the second opening / closing door and the first opening / closing door is opened when the tidal current is introduced into the tidal power generation device from the second opening. A step of introducing the tidal current from the first opening or the second opening into the tidal current power generation device to rotate a rotating body by the tidal current; A step of converting the rotation of the rotating body into electricity by a generator. A tidal current power generation method comprising these steps.

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