Wave energy recovery device and ship

Abstract

To provide a wave energy recovery device which generates electric power with wave energy, and to provide a ship.SOLUTION: A wave energy recovery device 5 includes: a pair of side tanks 51a, 51b formed so as to extend in a vertical direction; a bottom tank 51c which connects bottom parts of the side tanks 51a, 51b; a pair of floats 52a, 52b which are respectively disposed in the side tanks 51a, 51b so as to float on a liquid placed in the side tanks 51a, 51b and the bottom tank 51c; a rope 53 which connects the pair of floats 52a, 52b via the exterior of the side tanks 51a, 51b; a reel 54 which is disposed at an intermediate part of the rope 53 and around which the rope 53 is wound; and a power generator 55 connected to the reel 54.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wave energy recovery device and a ship, and more particularly to a wave energy recovery device capable of generating electricity by rocking the hull, and a ship equipped with the wave energy recovery device. [Background technology]

[0002] In recent years, green innovation has been called for in the field of shipping, given environmental issues such as the depletion of fossil fuels and global warming. In particular, for ocean-going ships that take a long time to complete a voyage, there is a need for technology that can obtain energy in some way during the voyage. When considering a ship while it is sailing, wave energy, which rocks the huge hull, is considered to be a major energy source.

[0003] Incidentally, an anti-rolling tank as described in Patent Document 1, for example, is known as a roll reduction device for reducing the rolling of a ship's hull while the ship is sailing or stopped.

[0004] The anti-rolling tank is equipped with a pair of wing tanks spaced apart in the ship's width direction on the port and starboard sides of the upper part of the hull at the widest point, and a duct connecting the wings. The wing tanks and ducts contain liquid, and the liquid moves in the ship's width direction between the pair of wing tanks via the duct, thereby reducing the rolling of the hull. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2015-163490 Summary of the Invention [Problem to be solved by the invention]

[0006] The current situation is that the above-mentioned anti-rolling tank is only used as a rolling reduction device, and does not utilize wave energy as an energy source.

[0007] The present invention has been made in view of the above problems, and has as its object to provide a wave energy recovery device and a ship that can generate electricity using wave energy. [Means for solving the problem]

[0008] According to the present invention, a fuel tank comprises a pair of side tanks configured to extend vertically, a bottom tank connecting the bottoms of the side tanks, a pair of floats arranged inside the side tanks so as to float on liquid contained in the side tanks and the bottom tank, and a rope connecting the pair of floats via the outside of the side tanks. a reel disposed in the middle of the cord body and around which the cord body is wound; a generator capable of generating electricity by the reciprocating motion of the cable body, a pair The reel moves back and forth due to the swing of the float. This reciprocating motion rotates the reel. A wave energy recovery device is provided, characterized in that the generator generates electricity.

[0009] The wave energy recovery device may include a guide means for guiding the cable to the generator.

[0010] The wave energy recovery device may include a duct connecting the upper portions of the pair of side tanks or an opening formed in the upper portions of the pair of side tanks.

[0011] The wave energy recovery device may include a guide member that guides the swing direction of the float.

[0012] The weight of the float may be set to be greater than the buoyancy when completely submerged.

[0013] The side tank and the bottom tank may have natural periods designed based on the peak value of a frequency characteristic curve of power generation potential assumed in a usage state.

[0014] According to the present invention, there is also provided a ship comprising a wave energy recovery device having any of the above-described configurations.

[0015] The pair of side tanks may be arranged along the longitudinal direction or the transverse direction of the hull.

[0016] The wave energy recovery device may be installed at a position spaced apart from the center of gravity of the ship in the length direction, height direction or width direction. [Effects of the Invention]

[0017] According to the wave energy recovery device and ship of the present invention described above, the rocking of the float can be converted into a reciprocating linear motion of the rope, and this reciprocating linear motion can be converted into electricity by a generator, so that the wave energy that rocks the float can be recovered and electricity can be generated. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is an overall configuration diagram showing a ship according to a first embodiment of the present invention. [Figure 2] 1A and 1B are plan views showing examples of the arrangement of a wave energy recovery device, where FIG. 1A shows a first embodiment and FIG. 1B shows a modified example. [Figure 3] 1A and 1B are partially enlarged views showing modified examples of the wave energy recovery device, where (A) shows a first modified example and (B) shows a second modified example. [Figure 4] 10A and 10B are diagrams showing an example of a tank shape design method, in which (A) shows the hull motion function, (B) shows the frequency spectrum, (C) shows a first example of a frequency characteristic curve of the power generation potential, and (D) shows a second example of a frequency characteristic curve of the power generation potential. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 4(D). Fig. 1 is an overall configuration diagram showing a ship according to a first embodiment of the present invention. Fig. 2 is a plan view showing an example of the arrangement of a wave energy recovery device, where (A) shows the first embodiment and (B) shows a modified example.

[0020] 1 and 2(A), a ship 1 according to a first embodiment of the present invention includes a hull 2 ​​constituting a floating body, a propeller 3 for propelling the hull 2, an accommodation space 4 arranged on an upper deck 21 of the hull 2, and a wave energy recovery device 5 arranged on the upper deck 21. Note that the configuration of the ship 1 shown in FIGS. 1 to 2(B) is exaggerated.

[0021] The ship 1 is, for example, a bulk carrier, and a hatch cover 22 is arranged on the upper deck 21. The ship 1 may be a cargo ship other than a bulk carrier, such as a tanker, a container ship, a ferry, etc. The ship 1 is, for example, a large ship, but is not limited to this.

[0022] The wave energy recovery device 5 includes, for example, a pair of side tanks 51a, 51b configured to extend vertically, a bottom tank 51c connecting the bottoms of the side tanks 51a, 51b, a pair of floats 52a, 52b arranged inside each of the side tanks 51a, 51b so as to float on the liquid contained in the side tanks 51a, 51b and the bottom tank 51c, a rope 53 connecting the pair of floats 52a, 52b via the outside of the side tanks 51a, 51b, a reel 54 arranged in the middle of the rope 53 and around which the rope 53 is wound, and a generator 55 connected to the reel 54.

[0023] The tank 51, which is made up of side tanks 51a, 51b and a bottom tank 51c, has an angular, roughly U-shaped configuration, and liquid such as seawater is pumped into it. When the tank 51 is placed on a horizontal surface, the side tanks 51a, 51b are configured to extend vertically, and the bottom tank 51c is configured to extend horizontally.

[0024] The liquid is supplied to the side tanks 51a, 51b so as to form an upper space above them that allows the liquid to move up and down. A duct 56 is arranged above the side tanks 51a, 51b to connect the upper spaces of the side tanks 51a, 51b. The duct 56 ensures the fluidity of air in the upper space between the side tanks 51a, 51b. Instead of the duct 56, an air vent valve may be arranged above each of the side tanks 51a, 51b.

[0025] The floats 52a and 52b have, for example, a vertically elongated shape, and have weights at the bottom that adjust the buoyancy and stabilize the floating posture. With this configuration, the buoyancy, floating posture, draft cross-sectional area, etc. of the floats 52a and 52b can be adjusted.

[0026] The weight W of the floats 52a, 52b is set to be greater than the buoyancy Δ when they are completely submerged. Therefore, the floats 52a, 52b have the relationship W>Δ=ρgV, where ρ is the density of the liquid in the tank 51 and V is the volume of the liquid. With this configuration, tension can always be applied to the rope 53 even when the floats 52a, 52b move up and down, and slack in the rope 53 can be suppressed.

[0027] Furthermore, although the gravity of the floats 52a and 52b is greater than the buoyancy at standard draft, by providing reserve buoyancy above the water surface, even if the rope body 53 is cut, the buoyancy and gravity of the floats 52a and 52b can be balanced in the liquid, thereby preventing damage to the tank 51.

[0028] The tank 51 rocks together with the hull 2, and the liquid levels in the side tanks 51a and 51b move up and down relative to each other. Therefore, the floats 52a and 52b move up and down relative to each other in accordance with the up and down movement of the liquid levels.

[0029] A cable 53 such as a wire rope is connected to the upper part of the floats 52a, 52b. The cable 53 is inserted through openings formed in the upper surfaces of the side tanks 51a, 51b. The cable 53 may be guided to the reel 54 by guide means 57a, 57b arranged on the upper parts of the side tanks 51a, 51b. The guide means 57a, 57b are, for example, pulleys. For ease of explanation, support members for supporting the guide means 57a, 57b are not shown in the drawings.

[0030] The reel 54 has a winding shaft for the rope 53. Both ends of the rope 53 are connected to the floats 52a, 52b, and the middle portion of the rope 53 is wound around the reel 54 by at least one turn. Therefore, the rope 53 is alternately pulled in the horizontal direction by the relative up and down movement of the floats 52a, 52b, causing it to move back and forth. This reciprocating movement of the rope 53 causes the reel 54 to rotate. For ease of explanation, the support member that supports the reel 54 is not shown in the drawing.

[0031] The generator 55 is a device that converts the rotational motion of the winding shaft of the reel 54 into electricity. The generator 55 has a rotating shaft that is rotated by the winding shaft of the reel 54. A power transmission mechanism such as a belt drive mechanism or a gear mechanism is disposed between the winding shaft and the rotating shaft. The power transmission mechanism may also include an amplifier or a ratchet mechanism that controls the direction of rotation in one direction.

[0032] In the above embodiment, the case where the reciprocating linear motion of the rope 53 is converted into the rotational motion of the reel 54 to generate electricity has been described, but the power generation method is not limited to this configuration. For example, the generator 55 may be a linear generator that converts the reciprocating linear motion of a permanent magnet arranged in the rope 53 into electric power.

[0033] As shown in Figures 1 and 2(A), the tank 51 according to the first embodiment has side tanks 51a and 51b arranged along the length of the ship. In addition, in this embodiment, the wave energy recovery devices 5 are arranged in two locations, on the port and starboard sides, in consideration of the balance of the hull 2. Furthermore, as shown in Figure 2(B), the tank 51 may have side tanks 51a and 51b arranged along the width of the ship.

[0034] Generally, rotational moments of roll (rolling) around the axis of rotation in the ship's length direction, pitch (pitching) around the axis of rotation in the ship's width direction, and yaw (swaying) around the axis of rotation in the ship's height direction are generated in the hull 2. In the first embodiment shown in Fig. 2(A), the pitch (pitching) generated in the hull 2 ​​is mainly utilized, while in the modified example shown in Fig. 2(B), the roll (swaying) and yaw (swaying) generated in the hull 2 ​​are mainly utilized.

[0035] Furthermore, the above-mentioned wave energy recovery device 5 is configured to convert the up and down movement of the floats 52a, 52a into reciprocating linear movement of the cable body 53 to generate electricity, and therefore can utilize all of the vibrations that occur in the hull 2, including roll (horizontal vibration), pitch (vertical vibration), and yaw (bowing).

[0036] The orientation of the tanks 51 is determined based on conditions such as the shape of the hull 2, the size of the tanks 51, the type of ship 1, and the expected sea conditions during the voyage of the ship 1. Generally, pitch (pitching) has a larger amplitude than roll (rolling) or yaw (yaw), so it is preferable to arrange the side tanks 51a, 51b along the length of the ship as in the first embodiment shown in Fig. 2(A).

[0037] The above-mentioned wave energy recovery devices 5 may be installed in multiple locations on the ship as needed, or may be distributed across different parts such as the upper deck 2, inside the hull 2, and the accommodation area 4. Also, wave energy recovery devices 5 with tanks 51 arranged in the longitudinal direction of the ship and wave energy recovery devices 5 with tanks 51 arranged in the transverse direction of the ship may be mixed.

[0038] 3A and 3B are enlarged partial views showing modified examples of the wave energy recovery device, with (A) showing a first modified example and (B) showing a second modified example. For ease of explanation, only the configuration of the side tank 51a side of FIG. 1 is shown in FIGS. 3A and 3B.

[0039] 3(A) and 3(B), a guide member 58 is arranged in the side tank 51a to guide the swing direction of the float 52a. By arranging such a guide member 58, it is possible to suppress the swinging of the floats 52a and 52b due to the six-degree-of-freedom movement of the hull 2.

[0040] The guide member 58 has, for example, a cylindrical shape. For example, the upper end of the guide member 58 is supported by a support member 59a connected to the inner surface of the ceiling of the side tank 51a, and the lower end of the guide member 58 is supported by another support member 59a connected to the inner surface of the side of the side tank 51a. For example, a plurality of support members 59a, 59b are arranged radially around the circumferential surface of the guide member 58. The shape and arrangement of the support members may be designed as desired.

[0041] In a first modified example shown in Fig. 3(A), a guide member 58 is provided in the tank 51 of the first embodiment shown in Fig. 1. In a second modified example shown in Fig. 3(B), an opening 51d communicating with the guide member 58 is formed in the ceiling of the side tank 51a. According to this second modified example, the duct 56 can be omitted.

[0042] Here, Figure 4 shows an example of a tank shape design method, where (A) shows the ship motion response function, (B) shows the frequency spectrum, (C) shows a first example of a frequency characteristic curve of the power generation potential, and (D) shows a second example of a frequency characteristic curve of the power generation potential.

[0043] In the graph of the ship motion response function shown in Figure 4(A), the horizontal axis represents the encounter wave period (sec) and the vertical axis represents the response value / (wave height / 2). In the graph of the frequency spectrum shown in Figure 4(B), the horizontal axis represents the encounter wave period (sec) and the vertical axis represents the wave spectrum (ω). Note that the graphs shown in Figures 4(A) and 4(B) are merely examples.

[0044] The frequency characteristic curve of the power generation potential shown in Figure 4(C) is obtained by multiplying the square root of the frequency spectrum of the sea state (wave height and wave period) assumed in the design by the response function of the pitching motion of the target ship for its average encounter angle with the waves. The first example of the frequency characteristic curve of the power generation potential shown in Figure 4(C) is a frequency characteristic curve created from the ship motion response function shown in Figure 4(A) and a sample of the frequency spectrum shown in Figure 4(B).

[0045] 4(C), when the peak value Pc of the frequency characteristic curve of the power generation potential is clear, the dimensions of the tank 51 (side tanks 51a, 51b and bottom tank 51c) are determined so that the period corresponding to the angular frequency at which the peak value Pc is obtained becomes the natural period of the tank 51. In other words, the natural period of the tank 51 (side tanks 51a, 51b and bottom tank 51c) is designed based on the peak value Pc of the frequency characteristic curve of the power generation potential expected in the usage state.

[0046] The second example of the frequency characteristic curve of the power generation potential shown in Figure 4(D) is a frequency characteristic curve created using a sample different from the ship motion response function shown in Figure 4(A) and the frequency spectrum shown in Figure 4(B).

[0047] As shown in Figure 4(D), if the frequency characteristic curve of the power generation potential does not have a clear peak or has multiple peaks that indicate values ​​close to the peak, the natural period may be adjusted as close to the short period side as possible (to the left side of the figure) to obtain more power. For example, the dimensions of the tank 51 (side tanks 51a, 51b and bottom tank 51c) are determined so that the period corresponding to the angular frequency at which the peak value Pd occurs is the natural period of the tank 51.

[0048] The vibration system, which is composed of the floats 52a and 52b, the rope 53, the reel 54, the generator 55, etc., may be designed to actively utilize the entrainment phenomenon by making the natural period of the vibration system approximately the same as the natural period of the liquid in the tank 51. The vibration system may also be designed to simply follow the liquid surface so that the natural period of the vibration system is not entrained in the natural period of the liquid in the tank 51.

[0049] The wave energy recovery device 5 described above has the characteristic that the greater the inertial force acting on the liquid in the tank 51, the greater the energy absorption effect that can be obtained. As shown in Fig. 1, the center of gravity of the hull 2 ​​is defined as G, the horizontal distance between the center of gravity G and the center of gravity G is L, the vertical distance from the bottom of the tank 51 to the bottom of the hull 2 ​​is H, the liquid level (the vertical distance from the bottom of the tank 51 to the liquid level) is Ht, the height of the tank 51 (the vertical distance from the bottom of the tank 51 to the upper end of the tank 51) is Dt, and the height of the center of gravity G (the vertical distance from the bottom of the hull 2 ​​to the center of gravity G) is Kg.

[0050] Therefore, it is preferable to install the tank 51 at a position as far away as possible from the position of the center of gravity G. Specifically, the tank 51 is installed so that the horizontal distance L or vertical distance H is as large as possible. It is also preferable to install the tank 51 at a position as far away as possible from the position of the center of gravity G in the ship's width direction.

[0051] However, when recovering wave energy by utilizing the pitch (vertical movement) of the hull 2, as in the first embodiment shown in Figure 1, a greater effect can be obtained by installing the tank above the center of gravity G than below it, even if the distance from the center of gravity G is the same. Therefore, H may be set to be greater than or equal to Kg.

[0052] Furthermore, in order to utilize the up and down movement of floats 52a and 52b arranged in tank 51, it is preferable to set the liquid level height Ht near the center of tank height Dt. In other words, it is set so that Ht≈Dt / 2.

[0053] According to the wave energy recovery device 5 and ship 1 of the present embodiment described above, the rocking of the floats 52a, 52b can be converted into a reciprocating linear motion of the rope body 53, and this reciprocating linear motion can be converted into electricity by the generator 55, so that the wave energy that rocks the floats 52a, 52b can be recovered to generate electricity.

[0054] In addition, by using the electricity recovered by the wave energy recovery device 5 on board the ship, the number of diesel generators installed on the hull 2 ​​can be reduced, and greenhouse gases generated when burning heavy oil can also be reduced.

[0055] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0056] 1 ship 2. Hull 3 Propulsion device 4 Living area 5. Wave energy recovery device 21 Upper Deck 22 hatch cover 51 Tank 51a, 51b Side tank 51c bottom tank 51d opening 52a, 52b Float 53 Chord body 54 reels 55 Generator 56 Duct 57a, 57b Guide means 58 Guide member 59a, 59b Support members

Claims

1. a pair of side tanks configured to extend in a vertical direction; a bottom tank connecting the bottoms of the side tanks; a pair of floats disposed inside the side tanks so as to float on the liquid contained in the side tanks and the bottom tank; a cable that connects the pair of floats via the outside of the side tank; a reel disposed at an intermediate portion of the cord body and around which the cord body is wound; a generator connected to the reel and capable of generating electricity by the reciprocating motion of the rope body, The reel is reciprocated by the swinging of the pair of floats, and the reel is rotated by this reciprocating motion, thereby generating electricity with the generator. A wave energy recovery device characterized by:

2. 2. A wave energy recovery device according to claim 1, further comprising a guide means for guiding the cable to the generator.

3. 2. The wave energy recovery device according to claim 1, further comprising a duct connecting the upper portions of the pair of side tanks or an opening formed in the upper portion of the pair of side tanks.

4. 2. A wave energy recovery device according to claim 1, further comprising a guide member for guiding the swinging direction of the float.

5. 2. The wave energy recovery device according to claim 1, wherein the weight of the float is set to be greater than the buoyancy when the float is completely submerged.

6. 2. The wave energy recovery device according to claim 1, wherein the natural periods of the side tank and the bottom tank are designed based on the peak value of a frequency characteristic curve of the power generation potential assumed in use.

7. A ship comprising the wave energy recovery device according to any one of claims 1 to 6.

8. The vessel according to claim 7 , wherein the pair of side tanks are arranged along the length direction or width direction of the hull.

9. The ship according to claim 7 , wherein the wave energy recovery device is installed at a position away from the center of gravity of the ship in the length direction, height direction, or width direction.

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