JP3218462B2 - Wave energy conversion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

[0001] The present invention relates to a small-sized wave energy conversion device which can be installed for an individual, and has a high efficiency in converting horizontal kinetic energy of wave force, which has been difficult to absorb even if it is separated. Highly efficient wave energy that can be used for power generation in remote islands and depopulated areas, for driving seawater desalination equipment, for aquaculture power, and for pumping deep water in cultivation and fishery. The present invention relates to a conversion device.

[0002]

2. Description of the Related Art Wind energy on the earth is partially turned into waves, and is relatively abundantly rushed to the coast as wave energy, but has not yet been fully utilized. Currently, most of the actual devices are pilot plants for demonstration tests, and there are no commercially available devices that can be easily used by civilians. The prerequisites for the practical use of wave energy converters are both low construction costs and extremely high energy acquisition and conversion efficiency. For this purpose, the present inventor has been deeply involved in the invention of the pendulum type wave power generation device of Japanese Patent No. 2539742 and the verification test at the Muroran Institute of Technology wave power generation demonstration plant named Penduler.
The principle is that the incident wave is guided into the caisson water chamber,
By actively utilizing the properties of waves as waves, the waves are converted into standing waves having a constant period for use. In this demonstration test, the average primary energy conversion efficiency was more than 60% of the world's best, and compared with data from other state-run plants,
An overwhelming advantage was confirmed. However, this generator has a capacity of 300 kW, requires a large investment in ancillary facilities such as caisson, and is a large-scale device on the premise that it is installed alongside a breakwater such as a breakwater. It was not a small device that could be used for personal use.

On the other hand, many small-scale individual-level inventions have been tried. However, most of them focus on the use of potential energy, which is half of the energy of wave power, and a wave energy conversion device that can use the kinetic energy of the other half of wave energy sufficiently efficiently cannot be realized. Was. The reason is simple. It is easy to extract the potential energy as the vertical movement of the wave force from the ups and downs of the floating body, but it was difficult to extract the kinetic energy in the horizontal direction. However, in remote islands and depopulated areas, it is desirable that small-sized devices with a capacity of about 10 kW or less be installed as efficiently as possible, and that new devices for small-scale use have been desired.

[0004]

The problem to be solved by the present invention is to realize the knowledge and know-how obtained by the present inventor for many years at sea in a wave power generation demonstration plant in a small wave power converter. Accordingly, an object of the present invention is to provide a wave energy conversion device which is low in cost and has a high energy conversion efficiency comparable to that of a pendulum type wave power generation device, and can be obtained even at an individual level.

[0005]

According to the present inventor's experience, the specific means for solving this problem is to determine the period of waves as a wave phenomenon and the natural frequency of the mechanical converter. This is all for realizing a mechanism for adjusting these two resonance conditions. As described above, in a device that converts only the ups and downs of a floating body into an energy, the technology for practical use was not so difficult. The reason is that the biggest factor that governs the natural frequency of this mechanical device is the magnitude of spring constant / floating mass, since the floating body motion is a vibrating system of spring action due to floating mass versus buoyancy. It was simple. That is, by adjusting the magnitude of the spring constant / mass of the floating body,
This is because the natural frequency of the mechanical device can be adjusted, and the resonance condition with the wave cycle can be realized relatively easily. 5 questions left
This mechanism aims to absorb the horizontal kinetic energy of the wave force occupying 0%. The above-mentioned pendulum device had a conversion mechanism specialized for absorbing the kinetic energy. The basis is a pendulum mechanism having a pressure receiving area of a certain level or more. This has the advantage of being the simplest mechanism, but if the pendulum is taken out of the water chamber and installed as it is in the sea, a water level change according to the displacement of the pendulum appears in the water chamber, and the spring action that was acting on the pendulum Since it disappears, it becomes extremely slow and cannot follow the wave cycle. That is, since the reduction of the natural frequency of the mechanism is a problem, it is only necessary to take measures to increase the natural frequency. To put it simply, the idea is to make the pendulum move faster.

[0006] For this reason, the inventor invented that the whole body completely jumps out of the sea surface as the floating body swinging in pendulum moves,
The idea was to attach an auxiliary floating body that would sink into the sea to the main floating body. As a result, when comparing the time when the auxiliary floating body is on the sea surface with the time when the auxiliary floating body is in the seawater, it is possible to easily realize a mechanism for giving a buoyancy moment change corresponding to the difference in specific gravity between air and seawater. The pendulum motion is a motion that alternately and completely converts the potential energy and kinetic energy of the pendulum alternately.However, when the auxiliary floating body jumps out on the sea surface, the potential energy of the entire floating body becomes the maximum. It is reasonable to equip the auxiliary floating body at the highest position with a moderate weight. The main floating body is a flat floating body in order to increase the pressure receiving area. The main floating body is provided with a floating portion having a volume enough to generate buoyancy by itself and a weight at the bottom to stabilize the floating body posture. In order to satisfy the resonance condition between the wave cycle and the floating pendulum motion, it is necessary to select an optimal distance between the flat floating body and the auxiliary floating body in consideration of the floating body size, the weight, and the mass of the floating body itself. When the wave condition, that is, the resonance condition changes, this distance is changed, and a water chamber having an appropriate volume is attached to and detached from the lower part of the flat floating body. Further, as a means for converting the motion of the floating body into energy, a pump is provided on a shaft that fixes the movement of the floating body above the floating body, so that seawater or the like is strongly pressed to obtain energy of high-pressure water. In addition, in order to simultaneously obtain the potential energy of the wave force, a base is provided on the sea or the like, and one end of a link member having a length equal to or greater than the assumed wave height is fixed to the base, and the flat floating body is attached to the free end of the other end. A pump dedicated to potential energy conversion was also provided at the shaft stopper at the base. In this way, the plate-like floating body is disposed on the wake side of the base fixed on the sea in a posture to receive the incidence of ocean waves from the front, and a vertical axis is provided at a shaft-stop portion on the base side of the link member, and this vertical axis is provided. , The link member is attached to the base. Here, the circular frequency of the ocean wave and the natural frequency of the floating body oscillating motion coincide as a certain value ω, and the distance R between the flat floating body and the auxiliary floating body when the resonance condition of both is satisfied is described in the specification. It is determined so as to satisfy the mathematical expressions described at the end, Expressions 1 and 2.

[0007]

(Equation 1)

[0008]

(Equation 2)

[0009]

In describing the operation of the wave energy conversion device of the present invention having such means, it is necessary to briefly describe the nature of ocean waves. An ocean wave is a wave phenomenon that is propagated while a group of water particles propagates in a regular motion, and is a traveling wave, and when viewed from the side, each water particle performs a circular motion. Each of the water particles has a phase difference between adjacent ones, and is added to the circular motion with a delay toward the downstream side. As a result, the crests and swells are observed as a result of the wind being blown downwind by the wind. An ocean wave consists of a combination of traveling waves of various wave heights and periods, and its power spectrum shows a peak at a certain wave height and period. It is represented by a regular wave having a peak height / period (substantially equal to the wave height / period of a significant wave) according to a custom, and is used in the description here. In the following description, an ocean wave refers to a significant wave, and it is assumed that only one set of wave height and period exists.

When a wave as an ocean wave comes into the wave energy conversion device of the present invention, the floating body starts to move up and down according to the height of the wave height. The link member fixed to the base is
According to the up and down movement of the floating body fixed to the free end, an up and down swing movement is caused. Since the link member has a relatively long dimension larger than the assumed wave height, a strong rotational torque by the principle of leverage acts on the pump on the base. At the same time, when the horizontal (front-to-back) kinetic energy of the ocean wave is applied to a large area of the floating body, the floating body hits the floating body and generates pressure, causing the floating body to swing in a pendulum motion. As described above, these series of motions are continuously generated by the circular motion of the water particles constituting the waves, but always involve the unwinding motion in the opposite direction because the circular motion is the cause. If the floating body cannot follow this swing-back movement, efficient conversion of wave energy cannot be performed. As described above, the key point is that the conditions under which the wave period and the natural frequency on the mechanism side can match, that is, the resonance conditions are adjusted. Adjustment of the load and the size of the floating body was good for absorbing the potential energy in the vertical movement, but means for speeding up the swinging of the floating body in the front-rear direction was necessary for absorbing the kinetic energy of the front-back movement. In the present invention, an auxiliary floating body that jumps out of the sea surface or sinks in the sea,
The main floating body is fixed at a predetermined distance. When the traveling wave acts on the flat floating body as the main floating body, the flat floating body that has been swung in the front-rear direction finally pushes the auxiliary floating body above the sea surface. As a result, the auxiliary floating body rapidly loses its buoyancy by jumping out onto the sea surface. The buoyancy of the auxiliary floating body has given the flat floating body a floating body moment in the direction to make the auxiliary floating body jump out of the sea surface, but this moment disappears rapidly, while the weight provided on the auxiliary floating body has the maximum potential energy. And exerts a floating body moment in the opposite direction on the flat floating body. The feature is that the switching speed and the rate of change of the floating moment from the plus direction to the minus direction at this time are high. As a result, the flat floating body can prepare for the kinetic energy absorption of the wave of the next cycle, following the swing back of the water particles due to the circular motion. At the time of switching from the minus direction to the plus direction following this, the sudden change of the floating body moment does not occur at the time when the auxiliary floating body jumps out, but since the auxiliary floating body is under the sea, always switch the direction of the floating moment. It exerts buoyancy and the underwater resistance of the auxiliary floating body, and in addition, the potential energy of the weight provided on the flat floating body is maximized, and the direction of the moment is switched. Even when the traveling wave hits the flat floating body, even if the direction change of the floating body moment is delayed, a stronger pressure is generated and a strong force is applied to the flat floating body to promote the direction change. In this way, the auxiliary floating body that jumps out into the sea surface or sinks into the sea plays a significant role in increasing the natural frequency of the flat floating body and adjusting the resonance condition with the wave period.

In the wave energy conversion device described in claim 2, the link member for suspending the flat floating body is attached to the base via a vertical axis, and the flat floating body is moored downstream of the base by the link member. Therefore, it can freely respond to changes in wind direction and changes in the direction of wave travel. When a wave force acts on the flat floating body from the lateral direction, a moment is generated in the flat floating body about the vertical axis, and the flat floating body is rotated in the downstream direction of the wave, and the flat floating body always receives ocean waves. In a posture where it is received from the front. At the same time, even if a tidal displacement occurs due to a difference in ebb and flow, if the link member swings around a shaft stop attached to the base, the displacement can immediately follow the displacement. When such a plate-like floating body is placed in an ocean wave, the rocking motion is repeated almost synchronously with the water particles that repeat the surrounding rotational motion. It is known that even if it oscillates greatly in apparent Shanghai water, it is almost synchronous with the surrounding water particles, so that the stirring resistance is very small. The force applied to the floating body by the oscillating motion of the flat floating body is inertial resistance based on the relative velocity difference between the floating body and the water particles, and is considered to receive the maximum force at the maximum amplitude of the oscillating motion. Therefore, even if the natural frequency of the flat floating body does not exactly match the circular frequency of the wave, if the frequency is close, a large inertial resistance is generated when the swinging motion direction is switched, and Is thought to be drawn into the resonance motion.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the illustrated embodiment. FIG. 1 is an explanatory diagram schematically showing a section of seawater near a shore where an apparatus of the embodiment is installed in order to explain the properties of ocean waves. The power source of ocean waves is wind energy in the atmosphere, but ocean waves are only traveling waves, and water molecules (particles) near the sea surface, except for the right end that hits the shore, as shown by the rotating arrow in the figure. If you repeat the rotational movement. Nevertheless, the reason why the crest moves continuously from the left offshore to the right shore in the figure toward the leeward is because the phases of the adjacent water particles gradually and gradually shift. Wave energy is divided into potential energy and kinetic energy, and its composition ratio is approximately 50% to 50%. The present invention aims at efficiently absorbing both of these energies by a small device.

FIG. 2 is a perspective view three-dimensionally showing an installation state in the sea of one embodiment of the wave energy conversion apparatus of the present invention. In the illustrated embodiment, a base 10 provided on the sea surface for mooring the wave energy conversion device is provided on the upper surface of a leg 11 having a length equal to or greater than the water depth, and these are integrated to form the turret 1. Make up. The turret 1 has its legs 11 fixed at the bottom of the seabed 9 and withstands waves to moor the converter at a fixed point. In the center of the base 10, a pump 7 having a shaft 70 as a central axis for fixing the link member 2 to the base 10 is firmly fixed. One end of the link member 2 is a bifurcated holder portion 20 for holding both ends of the shaft 70, and is connected to the shaft 70 with a strong key capable of transmitting a large rotational torque. The free end of the link member 2 is configured to be the housing of the other pump 8, and the center axis of the pump 8 also serves as the shaft 80 for fixing the floating body. The length of the link member 2 is at least as long as the expected wave height so that the floating body at the assumed wave height can be sufficiently moved up and down, and is relatively long in order to cope with tidal displacement. It has become. A pair of fixing members 30 are connected to both ends of the shaft 80 via strong keys, while the fixing members 3 are also provided on the upper surface of the flat floating body 4 in the floating body 3.
0 is fixed. The floating body 3 includes a flat floating body 4 as a main floating body, and an auxiliary floating body 5 fixed to the flat floating body 4 by a connecting plate 6 while maintaining a predetermined distance in parallel with the main floating body. The flat floating body 4 as the main floating body includes a wave receiving plate 41.
And a weight 42 at the bottom. The lower part of the floating portion 40 has a space for mounting a water chamber on the wave receiving plate 41 in preparation for a change in the natural frequency described later, and the mounting position of the connecting plate 5 can be changed. The dimensions of the auxiliary floating body 5 are 2 m in width, 1.5 m in height, and 0.6 m in thickness as specified in the paragraph [0021] described later, and the surface area thereof is 10.2 m ² in a rectangular parallelepiped. Since the auxiliary floating body 5 has rounded corners in order to reduce resistance when jumping out of the sea surface or submerging in the sea, the actual surface area is about 10 m ² . When the auxiliary floating body 5 is formed of a 5t steel plate, the weight of the auxiliary floating body 5 is approximately 400 kg as described in the paragraph [0021]. If the weight of the connecting plate 6 and the weight of the thickened portion of the portion where the floating body 5 is attached to the connecting plate 6 are added to this, the floating body 5 is provided with a weight of 600 kg without difficulty. In the drawings, the specific weight is not specified. On the other hand, the auxiliary floating body 5 is made of FR instead of steel plate.
In the case of using P or the like, a required weight is provided inside the auxiliary floating body 5 although not particularly shown. The auxiliary floating body 5 having the above dimensions and weight has a buoyancy of 1.8 tons in seawater and a buoyancy of 6 tons.
Due to the difference from its own weight of 00 kg, that is, the buoyancy of 1.2 tons and the distance between the master and slave floating bodies of 2.5 m, while generating a 3 ton-m counterclockwise rotation torque, 1.5 ton-m when jumping out onto the sea surface Will be generated. The change in the direction of the above-mentioned large torque from the counterclockwise direction to the clockwise direction when the auxiliary floating body 5 jumps out onto the sea surface depends on the condition that the rocking motion of the flat floating body 3 in the seawater can resonate with the wave cycle. Will play a decisive role in organizing. When the ocean wave travels from the left side in the figure to the floating body 3 moored on the sea via the tower 1, the base 10, the pump 7, the shaft 70, the link member 2, the shaft 80, the fixed member 30, and the like,
The link member 2 is swung up and down by the up and down movement of the floating body to prepare for the potential energy absorption by the pump 7. If the wave hits the flat floating body 4 and the floating body 3 swings back and forth around the axis 80, the pump 8 is used. Prepare for kinetic energy absorption.

FIG. 3 and FIG. 4 show a side view and a plan view of the embodiment shown in FIG. 2, respectively, which are related to the resonance conditions described in the section of the means for solving the problems. Symbols indicating dimensions and swing angles are also displayed. Vertically ups and downs swing angle of the link member 2 by the floating body 3 is presented as ± theta _h, the longitudinal direction swing angle of the wave is displayed as a ± theta _s. The thickness of the tabular floating body 4 is W _1, the thickness of the auxiliary floating body 5 is indicated by W _2. The distance between the flat floating body 4 and the auxiliary floating body 5 is represented by R. As shown in FIG. 4, the width of the flat floating body 4 and the width of the auxiliary floating body 5 are the same, which is indicated by B. Here floating body 3
When a wave force is applied to the floating body 3, the efficiency in the case of generating power from the vertical movement and the forward and backward oscillating movement of the floating body 3 is such that the natural frequency of the floating body 3 matches the wave frequency, and the floating body 3 and the waves resonate. It has been found that when the magnitude of the generator load can be matched to a certain optimum value determined from the wave input, the maximum occurs. Therefore, for the vertical movement and the back and forth swing movement of the floating body 3,
The device of the present invention is considered so as to satisfy both conditions of resonance with the wave. The natural frequency of the floating body 3 will be described. First, in the vertical movement of the floating body, the ratio of the mass of the floating body to its buoyancy is related to the natural frequency. The buoyancy can be regarded as the restoring force for the equilibrium position acting as a spring action.
Natural frequency ω _h of floating up and down motion is indicated by the number of equation (3).

[0015]

(Equation 3) Here, m: mass of the floating body (including a part of the pump 8 and the link member 2) k: spring constant shown by the mathematical formula 4

[0016]

(Equation 4) Here [rho: sea water density, g: gravitational acceleration B: floating body width, _{W 1:} thickness natural frequency omega _h of the floating portion 40, the floating body mass m, the floating body of the horizontal width B, thickness _{W 1} of the float portion 40 Therefore, it is easy to make it coincide with the circular frequency ω of the assumed ocean wave by performing an optimal design that meets the purpose. In the present invention, the natural frequency of the pendulum motion must also match the circular frequency ω of the assumed ocean wave. Assuming that the natural frequency of the back-and-forth swinging motion of the floating body is ω _s ,
Is the same as Here, I is the moment of inertia of the floating body around the axis 80, and K is the restoring moment coefficient shown by the above-mentioned equation (2). In Equation 2, W ₂ is the thickness of the auxiliary floating body 5, R is the distance from the axis 80 to the center of the auxiliary floating body 5. The floating body inertia moment I includes the influence of water around the floating body, and if the water chamber is attached to the floating body, the floating body inertia moment can be reliably and easily increased. The quickest way to adjust the restoring moment coefficient of K is to change the distance R between the floating bodies. Generally, when a floating body performing a pendulum motion is moored as it is in an ocean wave, the I value becomes extremely large. However, by attaching the auxiliary floating body 5 to the flat floating body 4, the K value corresponding to the increase of the I value is increased. Increase is easy. This facilitates matching ω _s with the circular frequency ω of the ocean wave. When ω _h and ω _s are made to coincide with ω in this manner, the floating body 3 violently moves up and down and rocks in the ocean wave, so that sufficient pressure water is supplied from the pumps 7 and 8. Can be.

FIG. 5 is a sectional view showing the basic structure of the pumps 7 and 8, FIG. 6 is a side view of the link member 2 including the pumps 7 and 8 at both ends, and FIG. Is shown. In FIG. 5, the suction circuit and the discharge circuit are indicated by symbols for explanation of the pump principle. In FIG.
A central shaft 70 (80) connects a pair of sturdy vanes 71, 71 oriented at 180 ° to each other,
It is pivotally fixed inside the case 73. Inside the case 73, a pair of partition walls 72 facing each other at 180 ° are fixed to the case 73. The case 73, the vane 71, and the partition wall 72 constitute four working chambers. The two chambers facing each other with the shaft 70 interposed therebetween have the same phase of increase and decrease in volume. Communicating with each other. A suction port 79 and a discharge port 81 communicating with a suction circuit 75 and a discharge circuit 76 are provided at a rising portion of the partition wall 72, respectively.
It leads to 7 and 78. The case 73 is firmly fixed to the base 10. Since the purpose is to generate high-pressure water, the thickness of the components cannot be reduced, and the swing angle of the shaft 70 is about 70 ° ± α. The swing angles θ _h and θ ₃ shown in FIG. There are restrictions due to the structure. However, when the link member 2 and the floating body 3 swing up and down and back and forth, the vane 71 swings while switching directions.
By the action of the check valves 77 and 78, the flow of the hydraulic fluid is always one-way from the suction side to the discharge side. The pumps 7 and 8 shown in FIGS. 6 and 7 have such a basic structure. As shown, the case of the pump 7 is fixed to the base 10, and the end of the link member 2 on the restraining side is a forked holder member 2.
0 and is firmly connected to the shaft 70, so that the shaft 70 also serves as a link pin, and the bearing of the pump 7 also serves as a pin bearing. Similarly, the free end of the link member 2 is constituted by the pump 8 itself, and the fixing member 30 connected to the shaft 80 thereof.
Is fixed to the floating body 3, the shaft 80 also serves as a link pin, and the pump bearing also serves as a pin bearing, which is the simplest and rational mechanism. Since the movement of the link member 2 and the floating body 3 directly swings the vane 71 of the pump, the rigidity of the power transmission path is high.

FIGS. 8 and 9 show the floating body 3 shown in FIGS. 2, 3 and 4 again. Here, the water chamber 43 is attached to the wave receiving plate 41 of the flat floating body 4. FIG. This state is shown again. The water chamber 43 has a case shape with an open upper surface. When the water chamber 43 is attached to the wave receiving plate 41 with bolts 44, the bottom surface of the floating portion 40 becomes a lid of the water chamber 43, and the seawater Is filled. In this case, since the seawater inside the water chamber 43 moves together with the floating body 3, the substantial floating body mass increases without changing the floating portion 40. It is very convenient as a means for adjusting the natural frequency ω _h of the above-mentioned. The connecting plate 6 connecting the flat floating body 4 and the auxiliary floating body 5 is fixed to the both by bolts 60. If the position of the bolt hole is changed, the distance between the two will also change, but this is because a mass-produced floating body of the same specification was considered so as to be adaptable to the sea surface under different wave conditions. The natural frequency of the floating body can be adjusted for each target sea surface in accordance with the frequency of the ocean wave. If the distance R in FIG. 3 is adjusted by changing the length of the connecting plate, the restoring moment coefficient K of Equation 2 can be adjusted.
As a result, the natural frequency ω _s can be adjusted very easily.

FIGS. 10 and 11 show examples of mooring structure of a floating body effective for protecting the apparatus of the present invention from a storm. FIG.
As shown at 0, the case 73 of the pump 7 is provided with a vertical shaft holder 13, and a vertical shaft 14 fixedly secured to the vertical shaft holder 13 causes the bearing 12 to bear against the base 10 of the tower.
It is mounted so that it can rotate. Therefore, even if the incident direction of the wave changes, a rotational moment about the vertical axis 14 acts on the floating body, and the floating body always faces the wave from the front. When the wave height increases, the swing angle of the floating body and the link member approaches the limit angle of the pump internal mechanism, and the wave force acting on the floating body does not exceed a certain limit. This safety effect is always maintained. In addition, since the floating body always faces the wave from the front, the efficiency of obtaining wave energy is high in normal times.

As in the case of the apparatus of the present invention, a common point of a device for acquiring wave energy using a moving object driven by a wave is the resonance between the target wave and the moving object, and the matching between the target wave energy and the load. Are key to efficiency determination. Based on the knowledge obtained from the inventor's experience, an attempt was made to predict the wave energy acquisition efficiency by the device of the present invention, and the results are shown in FIGS. 12 and 13 for reference. FIG. 12 shows the relationship between the energy acquisition efficiency η and the wave frequency ω. When ω coincides with the natural frequency ω ₀ of the floating body, the efficiency becomes maximum and decreases before and after. In particular, decrease in efficiency of when he became ω»ω ₀ is extreme. FIG. 13 shows the energy acquisition efficiency η with respect to the wave height change. Discharge pressures P1 _, P2 _, P of pumps 7 and 8
₃ is constant, and the pressure is P ₁ <P ₂ <P
There is a relationship of ₃ . The efficiency shows a peak value at a certain wave height, and decreases before and after that. The higher the pressure, the higher the wave height corresponding to the peak value. From the above considerations, it can be understood that if the floating body is resonated with the wave and the pump pressure is adjusted for the change in wave height to match the load, the device can be operated efficiently when acquiring the wave energy.

Finally, each specification of the embodiment of the present invention will be described. (1) Sea surface conditions where this device is installed Wave height of significant wave: 2 m, period of significant wave: 6 seconds, water depth: 3 to 8 m Average power of incident wave: 21 kW, Maximum power of incident wave: 40 kW (however, (2m width of floating body) (2) Floating body specification Flat floating body 2m wide x 2.5m high x 0.5m thick, own weight: 500
kg, weight: 500 kg, additional water: 500 kg, maximum buoyancy: 2000 kgf, spring constant: 1000 kgf / m, auxiliary floating body, 2 m wide x 1.5 m high x 0.6 m thick, own weight: 400
kg Weight: 600 kg, Maximum buoyancy: 1800 kg, Distance between master and slave floating bodies: 2.5 m Restoration moment coefficient: 7500 kgf · m (3) Planned output In case of pressure seawater Pressure 6 MPa _a Flow rate 90 m ³ / day In case of fresh water production 30 m ³ / In the case of daily power, average 5kw, maximum 10kw

[0022]

According to the present invention, in a single floating body type wave energy conversion device which is known to have a very large output with respect to the device size, a flat floating body with an auxiliary floating body capable of adjusting the natural frequency is provided. The natural frequency of the oscillating motion of the floating body in the front-rear direction is matched with the frequency of the wave to resonate, and the pumps at both ends of the link member mooring the floating body can independently realize high-efficiency energy conversion devices. . Because the two pumps are independent, they are free from the interaction of different movements, which is advantageous in increasing efficiency. Its energy conversion efficiency is high, comparable to pendulum wave power generation. In a power generator with a capacity of 3 to 10 kW, a power generation cost of about 10 yen per kW and 1
A construction cost of about one million yen per kW can be expected, and power generation efficiency of about 30 to 40% can be expected. If high-pressure seawater is guided to a hydraulic motor, it can be used as pump power for aquaculture, etc., and not only for deep-water pumping power but also can be obtained by pumping it to a filter of a seawater desalination apparatus. Since the present invention is a compact and simple wave energy conversion device, it is economical and excellent in durability, and can be a convenient energy source even in remote islands and coastal depopulated areas. Can be demonstrated.
In addition, the wave energy can be absorbed by highly efficient wave energy absorption, and it can be used as a simple breakwater facility that is far more economical than the construction of breakwaters. Here, a high wave-dissipating effect that cannot be seen with other wave energy conversion methods appears because the wave-making effect on the downstream side caused by the swinging of the flat floating body is caused by the auxiliary floating body immediately downstream from the sea surface. This is considered to be because the auxiliary floating body volume disappearing effect at the time of jumping up cancels out and the wave immediately after wave generation due to the swinging of the floating body is also eliminated by the auxiliary floating body jumping out. According to the present invention, the conversion efficiency can be improved at a stroke when compared with a conventional similar small wave energy conversion device.
Because it is an innovative technology that can be increased to about twice,
Its application value is extremely high.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of seawater in a coastal area for explaining the nature of waves.

FIG. 2 is a three-dimensional view showing a sea surface installation state of the wave energy conversion device according to one embodiment of the present invention.

FIG. 3 is a side view of the embodiment shown in FIG. 2;

FIG. 4 is a plan view of the embodiment shown in FIG. 2;

FIG. 5 is a longitudinal sectional view of main components of a pump device that performs energy conversion according to an embodiment of the present invention.

FIG. 6 is a partially longitudinal side view of a link member provided with the pump of FIG. 5 at both ends.

FIG. 7 is a plan view partially crossing the link member of FIG. 6;

FIG. 8 is a side view of a flat floating body having a water chamber according to one embodiment of the present invention.

FIG. 9 is a front view of the flat floating body shown in FIG. 8;

FIG. 10 is a partial longitudinal sectional view of a mooring portion showing a vertical axis for mooring a floating body according to one embodiment of the present invention.

11 is a plan view of the mooring section shown in FIG.

FIG. 12 is an XY coordinate graph showing the relationship between the wave frequency ω and the energy acquisition efficiency η for a floating body having a certain natural frequency.

FIG. 13 is an XY coordinate graph showing the relationship between the change in wave height and the energy acquisition efficiency η.

[Explanation of symbols]

 1 Tower 10 Base 11 Leg 12 Bearing 13 Vertical axis holder 14 Vertical axis 2 Link member 20 Holder 3 Floating body 30 Fixed member 4 Flat floating body 40 Floating part 41 Wave receiving plate 42 Weight 43 Water chamber 44 Bolt 5 Auxiliary floating body 6 Connecting plate 60 Bolt 7 Pump 70 Shaft 71 Vane 72 Partition wall 73 Case 74 Working chamber 75 Suction circuit 76 Discharge circuit 77, 78 Check valve 79 Suction port 8 Pump 80 Shaft 81 Discharge port 9 Submarine

Claims (3)

(57) [Claims] 1. A base fixed on the sea surface or on the coast, a link member having one end fixed to the base and having a length equal to or greater than an assumed wave height, and a seawater fixed to a free end of the link member. In addition to having a floating portion at the top that is capable of oscillating mooring and generating buoyancy even in a single body, in addition to a flat floating body with a weight at the bottom, the swinging motion of this flat floating body is An auxiliary floating body fixed to the flat floating body at a predetermined position that satisfies the resonance condition and the entire body completely jumps out of the sea surface or submerges in the sea due to the oscillating motion thereof; The auxiliary floating body is provided with a weight of sufficient weight including the auxiliary floating body's own weight, while the pump on the base portion has a potential energy due to the vertical movement of the floating body. In preparation for wave power absorption, A wave energy conversion device, wherein the pump on the floating body side is provided for absorbing the kinetic energy of the wave force due to the swinging motion of the floating body. 2. A flat floating body is disposed on the downstream side of a base fixed on the sea surface in a posture to receive the incidence of ocean waves from the front, and a vertical axis is formed in a shaft stopper of the link member. 2. The wave energy conversion device according to claim 1, wherein the shaft stop is attached to the base via the base. 3. The auxiliary floating body has a detachable water chamber below the floating portion so that the resonance condition with the waves can be maintained even when the wave conditions change, and the predetermined distance from the auxiliary floating body can be changed. The wave energy conversion device according to claim 1, further comprising a connecting plate.