JPS5912807B2 - Tidal power generation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel power generation method that utilizes the flow velocity and pressure of tidal currents as a power generation energy source.

Well-known hydroelectric power generation, thermal power generation, and nuclear power generation are currently subject to major restrictions on location in terms of pollution prevention, environmental conservation, and safety, and water (which is the energy source for these power generation)
There is no hope for a future as the resources such as rivers, oil, and uranium have been almost exhausted or are beginning to be depleted, so in parallel with experimental research on nuclear fusion reactors, we are trying to develop almost all of the earth's resources, such as geothermal, solar, wind, and ocean energy. Various power generation methods using inexhaustible natural energy have been proposed, and some are already in the stage of being put to use.

Among these, those that utilize ocean energy are tidal level power generation,
This power generation method, probably due to wave power generation, has the difficulty of extracting a constant amount of power continuously for a long time, and the problem is that the output power is too small considering the enormous cost.

In other words, with these power generation methods, seawater only moves slowly over time, and the amount of energy that can be extracted per unit time is too small.

In view of the above points, the present invention focuses on tidal currents as a result of various studies in order to efficiently extract the vast amount of energy contained in the ocean, and develops a power generation method that converts the tidal velocity pressure of this tidal current into effective power generation energy. I came up with a idea.

That is, tidal currents are caused by the periodic flow of seawater associated with the tides, and the currents in the ocean are weak, and as is, only a small amount of energy can be extracted as in the above-mentioned tidal level power generation.

However, tidal currents flow in a straight line in waterways, straits, etc., and although they temporarily lose speed during diversion, they continue to flow almost all day long, and the current speed at its highest is quite high.

For example, according to the 1971 Seto Inland Sea tide table (supervised by the Japan Coast Guard Hydrographic Department), the maximum current speed of the west current at the February 24th station in the Akashi Strait was 5 knots, and the maximum current speed of the converging stream was 4 knots, which is a huge amount. It can be seen that it contains kinetic energy.

It is relatively easy to install a power plant in a place where tidal currents flow linearly and have high tidal current speeds, such as the aqueducts and straits mentioned above, and turn water turbines using the flow velocity pressure of the tidal currents. Not only can a large amount of generated energy be extracted, but also stable power can be supplied continuously throughout the day, except for a short period of time during commutation.

Further, to explain the principle configuration of the present invention with reference to FIG. 1, an artificial power generation island (seaside structure) 1 is constructed on the sea in a place where the tidal current speed is relatively high, such as an aqueduct or a strait, and which does not impede the navigation of ships. A seawater introduction passage 2 is linearly opened in this artificial island 1, passing through the artificial island 1 in the direction of the tidal current, so that the seawater riding on the tidal current flows into and passes through the seawater introduction passage 2 as the seawater flows. At the same time, a water wheel 3 pivotally supported in the middle part of the seawater introduction path 2 is rotated by the flow velocity pressure of seawater, and a generator 4 interlocked with the water wheel 3 is driven to generate electricity.

5.6 are water intakes provided at both ends of the seawater introduction channel 2. When seawater flows from the water intake 5 during collection, the other water intake 6 acts as a water outlet, and vice versa when the water flows westward. It is configured to perform the following functions.

In addition, as seen in the figure, the water intakes 5 and 6 gradually widen outward in a fan shape, and as the seawater flowing into the water intakes 5 and 6 reaches the inner depths of the water intakes 5 and 6, the width further increases. The velocity of the flow is increased to 1 so that it hits the water wheel 3.

This is to increase the speed and pressure of the seawater acting on the water turbine 3 more than the actual tidal current speed to increase power generation efficiency.

That is, when a fluid flows continuously inside the tube, the weight flow rate W of the fluid is constant regardless of the cross section of the tube.

This can be expressed as a formula.

However, r is the specific weight (for example, in the case of water, 1000 kg/m3
), A is the cross-sectional area (m”), and v is the average flow velocity (m/s).

If the density (specific weight) of the fluid is constant like seawater, the volumetric flow rate Q (m'/s) will also be constant at any cross section and can be determined from the equation Q-AV.

Now, in the fan-shaped water intakes 5 and 6 as shown in Fig. 1, the volumetric flow rate at the widest part at the tip is Ql, and the volumetric flow rate at the narrowest part at the innermost part is Q1.
2, the maximum width at the tip is 100m1, the narrowest width at the back is 10m1, each water depth is Ion, and the seawater flow velocity (that is, the flow velocity of the tidal current flowing into the water intake) at the maximum width at the tip is 3000m/h. When calculating the seawater flow velocity v2 at the innermost narrowest part using the above formula, we get
will be rotated.

Therefore, by appropriately designing the cross-sectional area ratio A1:A2 of the water intakes 5 and 6, the power generation energy can be increased by arbitrarily increasing the tidal flow velocity with respect to the tidal current velocity.

The above is the principle structure of the present invention, but in actual use, as shown in FIGS. 2 to 4, the introduction channel 2 is connected to the partition wall 7... It is divided into a plurality of (four in the drawing) parallel small waterways 8 to 11, each of which is equipped with water gates 12 to 15, and only an arbitrary number of small waterways 9 and 10 are equipped with the water turbine 3,
3, the other small channels 8 and 11 are used exclusively for discharge, and the flow rate of seawater acting on the water turbines 3 and 3 is controlled by adjusting the opening and closing of the water gates 12 and 15 of the small channels 8 and 11 exclusively for discharge. .

That is, since the tidal current has the property of changing its flow speed over time, the flow rate of seawater acting on the water turbines 3, 3 also changes in proportion to this change in flow speed.

That is, the volumetric flow rate Q changes. Furthermore, since the amount of water submerged in the water turbines 3, 3 changes due to changes in the tide level, this also affects the flow rate of seawater acting on the water turbines 3, 3.

Therefore, the power generation capacity changes due to these causes, and it becomes impossible to obtain average power.

Therefore, when the tidal current speed is high, the water gate 12.15 is opened wide to increase the amount of water released and suppress the flow rate of seawater per unit time acting on the water turbines 3, 3, and conversely, when the tidal current speed is decreasing, the water gate 12.15 is opened wide. 15 is closed to reduce the amount of water released, and water wheel 3 is closed.
, 3 is increased, thereby compensating the energy for the decrease in tidal current speed.

The same applies to changes in the tidal level, and in this way it is possible to obtain approximately average power except for a short time before and after the commutation when the tidal current speed is almost zero.

Furthermore, water gates 13 of small channels 9 and 10 equipped with water turbines 3 and 3
, 14 can be subjected to the same adjustment control as that for the water gates, and more stable electric power can be taken out.

Moreover, water gates 12 to 15 are provided at both ends of each of the small channels 8 to 11, taking into account that the direction of the tidal flow is reversed.

In the drawing, each of the water gates 12 to 15 is opened and closed (
However, this opening/closing mechanism is not particularly limited.

Further, 18 indicates a shaft of the water turbines 3, 3, and 19 indicates a bearing member for this shaft.

Furthermore, if the seawater that hits each water wheel 3, 3 is rippling, the rotational efficiency of the water wheel 3, 3 will decrease accordingly, so wave shielding plates 20, 20 are installed at the inner depths of each water intake port 5, 6. Try to eliminate waves.

Furthermore, the seawater flowing into the water intakes 5 and 6 is efficiently transferred to the water turbines 3 and 3.
As shown in Figure 4, concrete is poured into the bottom of the water intakes 5 and 6 to form a sloped wall 21 with an upward slope, and the seawater flowing into the water intakes 5 and 6 is directed towards the water turbines 3 and 3. It is beneficial to configure the system so that it is concentrated on one point.

In this case, in order to prevent seawater from overflowing from the inlet channel 2 due to excessive water pressure acting at the back of the water intake 5°6,
A cover 22 as shown in FIG. 4 may be placed over the narrowest part of the introduction path 2.

When the direction of the tidal flow is reversed, the rotational directions of the waterwheels 3, 3 will be different, but this can be always input to the generator 4 by using appropriate means with the rotational direction of the waterwheels 3, 3 as a unidirectional rotational force.

In addition, 23 in FIG. 1 is land, and 24 is this land 23.
A bridge connecting the artificial island 1 and the artificial island 1 is shown.

As is clear from the above detailed description, the present invention can provide the following effects.

The present invention focuses on energy caused by the flow velocity and pressure of tidal currents, and generates electricity by impinging on and rotating a water wheel.

Therefore, although tidal currents in the ocean are weak, if the power generation method of the present invention is applied to areas where the tidal current direction is linear and the tidal current speed is slow, such as in aqueducts or straits, the enormous kinetic energy of this tidal current can be absorbed. It can be converted into power generation energy, and it is possible to extract significantly more power than conventional tidal level difference power generation methods and wave power generation methods.

○ In addition, instead of simply letting the seawater hit the waterwheel at its natural tidal current speed, the tidal water speed is increased as it reaches the inner depths of the waterway through a fan-shaped water intake that is gradually widened, and then it hits the waterwheel. As a result, the generated energy can be increased more efficiently, and even more electric power can be extracted.

○ It is particularly useful if the widening ratio of the fan-shaped water intake is designed to match the tidal current speed of the sea area to which the present invention is applied, since it is possible to generate the desired amount of power regardless of the magnitude of the tidal current speed. In this respect as well, it is an extremely superior power generation method compared to conventional tidal level difference power generation methods.

○ Moreover, simply by penetrating the artificial island with an introduction channel in the direction of the tidal flow and making the water intakes at both ends of the introduction channel fan-shaped, seawater will naturally flow in and increase the speed according to the speed of the tidal current, and the above-mentioned large amount of electric power can be obtained. Therefore, the cost is greatly reduced, and the power generation cost can be easily lowered to a practical level.

○ In particular, since our country has areas with strong tidal currents in inland sea areas and surrounding areas, if the tidal current power generation of the present invention is applied to these areas, the total amount of electricity that can be obtained will be enormous.

○ Since the tidal current does not lose its velocity except for a short time before and after the commutation, it has the advantage of being able to generate electricity continuously for most of the day.

○ In particular, in the present invention, the seawater introduction channel is divided into a plurality of parallel small channels, one or more of these channels is equipped with a power generation water turbine, and the other small channels are used as waterways exclusively for discharge. Since the water turbine is rotated while controlling the flow rate of seawater in the exclusive waterway, it is possible to always obtain approximately average power despite changes in the tidal current velocity over time.

○ Furthermore, a wave shielding plate is installed near the entrance of the seawater introduction channel,
Since the power generation water turbine is rotated while the waves are damped by this wave shielding plate, it is possible to prevent the rotational efficiency of the water turbine from decreasing due to seawater waves and to effectively absorb tidal energy.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the principle of the tidal current power generation method according to the present invention, FIG. 2 is a plan view of essential parts showing one embodiment thereof, FIG. 3 is a front view thereof, and FIG. 4 is a side sectional view. 1... Marine structure, 2... Seawater introduction channel, 3... Power generation water turbine, 4... Generator,
5, 6...Water intake, 8-11...Small channel, 20...Wave shielding board.

Claims (1)

[Claims] 1. A seawater inlet channel is installed in a marine structure located in a sea area with high tidal current speed in parallel to the direction of the tidal current, and the width of the intake port of this seawater inlet channel is gradually widened so that the intake port opens outward and takes on the shape of a fan. At the same time, a water turbine for power generation is installed in the seawater introduction channel which is the narrowest width part, and the seawater flowing into the seawater introduction channel from the water intake at a tidal current speed is increased to the maximum speed in the seawater introduction channel which is the narrowest width part. In the tidal current power generation method in which the seawater tidal energy is used to rotate a power generation water turbine, the seawater introduction channel is divided into a plurality of parallel small channels, and the power generation water is supplied to one or more of the small channels. In addition to equipping cars, other small waterways were designated as waterways for exclusive use of water discharge, and a wave shielding board was installed near the sunset of the seawater introduction channel, and this wave shielding board was used to eliminate waves.
A tidal current power generation method in which the water turbine is rotated while controlling the flow rate of seawater in the discharge waterway.