JPH11351120A - Tidal power generating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To economically and stably generate electric power by transmitting motion of a floating tank moving vertically according to the fluctuation of a water level due to a tidal difference to a piston in a hydraulic cylinder and rotating a hydraulic motor by means of oil pressure generated in the hydraulic cylinder. SOLUTION: When a tidal condition is transferred from a high tide to a low tide, a floating tank 2 lowers because of its self-weight, and its motion is transmitted to a piston 4 in a hydraulic cylinder 3 so as to push out oil in a first cylinder chamber. This oil passes through a direction switching valve and a flow rate control valve so as to rotate a hydraulic motor in a hydraulic power generator 5, and consequently, power generation is carried out. On the other hand, in this process, oil inside an oil tank is led into a second cylinder chamber of the cylinder 3 via the direction switching valve. Subsequently, in a high tide time, the floating tank 2 is lifted and the piston 4 in the hydraulic cylinder 3 is lifted so as to push out oil in the second cylinder chamber. Similarly, the oil is fed to the hydraulic motor in the hydraulic power generator 5 so as to rotate the motor, and consequently, power generation is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tidal power generation method for generating power by using the energy of vertical movement of the water level at a tidal range.

[0002]

2. Description of the Related Art There are tidal power generation systems in the Reims region of France and Annapolis in Canada. In Japan, this method was once examined in the Ariake Sea, but the economics were low, and no concrete plans were made. In addition, research on wave power generation (Yamagata Prefecture, Mie Prefecture, etc.), which converts energy from waves into air pressure by a pressure device to generate power, has been conducted. However, as in the present invention, the vertical movement of the water level at the ebb and flow of the tide is used as a floating tank. There is no other method of generating electricity by changing the energy of gravity and buoyancy through a hydraulic system and driving a generator by a hydraulic device.

[0003]

Conventionally, small-scale power generation by sunlight, wind power, wave power and the like by natural energy is seen, but the power generation amount is largely influenced by weather conditions and is unstable.

Accordingly, the present invention provides a new tidal power generation method using a tidal range to solve such a problem.

[0005]

In order to solve the above-mentioned problems, a tidal power generation method according to the present invention uses a sea berth (installed on the sea) in which a pressure device is installed in an inlet, a bay, and other sea areas where the tide is relatively large. Pier), a floating tank that creates gravity and buoyancy (water tank floating in the sea), and a pressure device to drive the generator, enabling power generation.

[0006] There are known techniques for pressure devices, such as hydraulic, pneumatic and hydraulic. Utilization of water pressure has drawbacks such as rusting, freezing and evaporation, and pneumatic pressure has a limitation on the working pressure of a pneumatic machine, so that the compression ratio is large and it is difficult to handle.
Further, if the pressure device has a mechanical structure, it becomes very complicated with gears, chains, cams and the like. Therefore, at this stage, by adopting the hydraulic pressure for the pressure device, the generator can be driven by connecting the hydraulic device with a pipe or a hose. Hydraulic equipment is installed on the sea berth and covered with a cover to protect it from salt damage.

[0007] The floating tank is stationary at one place and only generates gravity and buoyancy. Since the floating tank is not exposed to fast-moving tidal currents and ocean currents, it is necessary to take relatively strict attention to the structure's ruggedness. do not do. Therefore, if a tanker abandoned ship is modified, it can be reused as a floating tank. In shallow places from the sea surface to the sea floor, the construction of a floating tank can be achieved by increasing the width of the floating tank and reducing the draft. Therefore, it is possible to adjust the size and shape of the floating tank according to the depth of the sea and build the tank.

The amount of power generation can be easily increased by increasing the volume of the floating tank or increasing the number thereof.

[0009]

The energy of gravity and buoyancy of a floating tank that moves up and down due to the ebb and flow of the tide can be generated by driving a generator through a hydraulic device installed on a sea berth. Even in places without ocean currents, tides and waves, and without large bays like conventional tidal power generation, power can be generated in any sea area if there is a minimum required effective area and tidal range.

[0010]

Embodiment 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a sea verse, 2 is a floating tank, 3 is a cylinder, 4 is a piston, and 5 is a hydraulic power generator. 2 and 3, reference numeral 6 denotes a direction switching valve, 7 denotes a flow control valve, 8 denotes a hydraulic motor, 9 denotes a generator, 10 denotes a strainer, and 11 denotes an oil tank. When the floating tank 2 moves from high tide to low tide, the gravity of the floating tank 2 causes the cylinder 3
The piston 4 pushes out the oil in the chamber a, and rotates the hydraulic motor 8 of the hydraulic power generator 5 through the directional control valve 6 and the flow control valve 7. The generator 9 is driven by the rotation of the hydraulic motor to generate power. The oil enters the oil tank 11 through the strainer 10 and enters the chamber b of the cylinder 3 through the directional valve. At low tide, the piston stops moving and the switching valve is activated. Eventually, when the tide rises, the buoyancy of the floating tank causes the piston of the cylinder to push out the oil in the chamber b and rotate the hydraulic motor of the hydraulic power generator through the directional control valve and the flow control valve. The generator is driven by the rotation of the hydraulic motor to generate electricity. Oil enters the oil tank through the strainer and enters the a-chamber of the cylinder through the directional valve.

Calculation of power generation by potential energy conversion Potential energy: U (N) = Wh Weight: W (kg) Tidal difference: h (m) Work load: J (Nm) Time (second): t (s) Now Using a 50,000 ton floating tank (100m long x 30m wide x 15m high), calculate the amount of power generation by potential energy conversion at the time of a high tide (about 5 hours from high tide to low tide) in a sea area with a tidal range of 3m Then, U = Wh = 50,000 × 1000 Kgf × 9.8 × 3 = 1,470,000,000 Nm Power generation amount P = Wh / t = 1,470,000,000 / 60 × 60 × 5 ≒ 82,000 Nm / s That is, it can generate power for 5 hours with an output of about 82 kW.

Calculation of power generation by hydraulic pressure Commercially available inner diameter 230Φmm, pressure P350kgf / cm ²
Oil pressure F = pressure P (kgf / cm ² ) × flow rate Q (liter / min) Force received by piston = area S × pressure P 415 × 350 = 145250 = 145 (ton) Number of cylinders when the weight is 50,000 tons 50,000 tons ÷ 145 tons = 345 cylinders When the piston of a cylinder moves over a 3 m ebb and flow in 5 hours, it becomes 300 cm / 60 × 5 = 1 cm / min. Flow rate is 415cm ² × 1cm = 415cm
³ (0.415 liter) Oil pressure F = P × Q = 350 kgf / cm ² × 0.415 liter / min = 350 × 10 ⁴ × 9.8 × 0.415 × 10 ^-3 × 1/60 ( m ³ /s)=237.2 Nm / s That is, one cylinder outputs 237.2 w. 237.2 × 345 = 8 for a 345 cylinder
1.8 kW, which is almost the same as the potential energy.

The power generation amount of 81.8 kW is a theoretical calculation value. If the power generation efficiency is 60%, the actual power generation amount is about 50 kW. To increase the power generation to 3,000 kW, about 60 50,000 ton floating tanks are required.

Tide twice a day (differences between day and night are different)
Is repeated, the power is always generated except when the power generation is temporarily stopped four times at the time of the transition from the rising tide to the ebb tide, or at the time of the transition from the ebb tide to the ebb tide. It should be noted that the power output is reduced during the week of the ebb tide because the difference in ebb and flow is small. Incidentally, Japan has a smaller tidal gap nationwide than other countries. The waters that are relatively advantageous for tidal power generation for Japan are west of the Tokai region, especially the Seto Inland Sea and the Kyushu Ariake Sea. To be specific, the ebb and flow of the approximate values at the time of the spring tide at the main points are: Nagoya 2m, Yokkaichi 2m, Mizushima 2.5-3m, Onomichi 3m,
Hiroshima 3m, Tokuyama 2.5-3m, Matsuyama 3m, Niihama 3m,
Miike 3-4m, triangle 3-4m, Sasebo, Nagasaki 2-2.5
m etc.

[0015]

[Effect of the Invention] 1. Tidal power generation uses clean natural energy, so there is no need to worry about depletion of resources and air pollution.
Furthermore, power generation is possible without being affected by weather such as day and night, cloudy weather, wind, and waves. 2. If the monthly tidal difference is calculated from the tide table, the expected power generation can be calculated in advance. 3. The bays and rivers, which are said to have a significant impact on the environment, are not blocked by sluice gates, and do not hinder the navigation of ships and the movement of fish. 4. It is possible to generate electricity even in small, quiet bays and tap water where the tide is weak. 5. The construction cost of the sea berth and the equipment cost of a large amount of hydraulic equipment will be a large cost burden at first, but since the movement of the piston of the hydraulic equipment is two reciprocations a day, it is not a heavy use but once completed, it will take a long time Can be used. In addition, if the seabed of the sea berth is made into a structure that becomes a fish nest, or if seawater is filled in a floating tank and it can be used as a farm for fish and shellfish, in return for the sea area occupied by the tidal power generation facility, the local people It will create a new aquaculture industry and create additional economic benefits. 6. Although the amount of power generation is small, the tidal power generation method of the present invention, which can be applied to the coastal landforms of Japan and small ebb and flow, plays a role of supplementing the minimum necessary power supply in an emergency.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a tidal power generation method of the present invention.

FIG. 2 is an explanatory view of a hydraulic power generator at the time of ebb tide according to the present invention.

FIG. 3 is an explanatory diagram of a hydraulic power generating device at the time of rising tide according to the present invention.

[Explanation of symbols]

 1, sea berth 2, floating tank 3, cylinder 4, piston 5, hydraulic power generator 6, directional switching valve 7, flow control valve 8, hydraulic motor 9, generator 10, strainer 11, oil tank.

Claims (1)

[Claims] An energy generated by gravity and buoyancy of a floating tank which moves up and down due to a movement of a water level at a tidal range is transmitted to a piston of a hydraulic cylinder directly connected to the floating tank, and the hydraulic motor is rotated by the vertical movement of the piston. A tidal power generation method characterized by driving a generator by causing the power to be generated.