JPH07259064A - Caisson for ocean current power generation - Google Patents

Abstract

PURPOSE:To convert the ocean current energy into a large capacity electric power free from risk of generating a pollution which can be achieved by collecting the ocean current energy because the density of the flowing water energy per unit time and per unit area perpendicular to the ocean current is small despite a tremendous quantity in total of the ocean current energy. CONSTITUTION:In an oceanic region having an ocean current, a buoy B equipped with a conduit A directly confronting the stream is moored by its bow part. The conduit A has a water intake 1 at the bow in its whole surface and a water exhaust hole 2 at the stern. The central part of the conduit A is formed with a circular section having an area several percent of the water intake section area perpendicular to the ocean current, and there a hydraulic wheel 6 is mounted so that a power generator C is operated. The buoy R is submerged so that the center of the rotary shaft of hydraulic wheel 6 reaches a depth equal to the velocity head of the ocean current stream in the position of hydraulic wheel 6, and the whole current having come to the water intake 1 is taken in. An intermediate buoy D may be used in an oceanic region where the water depth exceeds several hundreds of meters.

Description

Detailed Description of the Invention

[0001]

[Industrial application] In the current large-capacity power generation, there are structural problems such as air pollution in thermal power generation, radioactive contamination in nuclear power generation, and decrease in suitable sites for hydropower generation. Requires a large initial investment. Currently, what is needed is an economical, large-capacity power generation system that uses unlimited resources, is free of pollution. The ocean current power generation submersible of the present invention is positioned here.

[0002]

2. Description of the Related Art The ocean current flowing through the ocean has a magnificent energy as will be described later, is supplied infinitely, and has a stable flow velocity and direction. Focusing on the magnificent energy of this ocean current and its properties, researchers in various countries have made many proposals for ocean current power generation systems by about 1980. However, many of these proposals, although diverse in methods and means, basically put propellers and turbines in the ocean current and convert their rotational motion into electrical energy, except for strange ones. . However, even if the total amount of ocean current energy is magnificent, the density of running water energy flowing in a unit area perpendicular to the ocean current flow per unit time is too lean for large-capacity power generation. Since the output calculation of the ocean current power generation is proportional to the cross-sectional area of the turbine that is perpendicular to the ocean current and proportional to the cube of the current velocity of the ocean current, in expectation of high output, we increased the turbine and propeller to obtain a high-speed ocean current. However, due to the increase in the size of the structure, it is not possible to develop the strength of the structure, the working method, and the mooring and installation of the structure, and the construction cost increases, and the economical efficiency corresponding to the power generation output cannot be obtained. It is the current state of technological development of ocean current power generation that tests have not yet been conducted at sea. Current ocean power generation is completely forgotten in recent clean energy books.

[0003]

Even if the total amount of ocean current energy is magnificent, the density of flowing water energy per unit time per unit area perpendicular to the ocean current is low. It is an object of the present invention how to condense the energy of such ocean currents and to extract a large amount of electric power with a device that is pollution-free and economically profitable.

[0004]

In order to solve the above-mentioned problems, the floating body B shown in FIGS. 1 to 4 is moored to the sea area with the ocean current, and moored from the bow with the intake port 1 to the sea bottom with mooring lines 9 and anchors 10. To do. Since the floating body B is unmanned, in order to dive, float, and adjust the depth of the floating body B, the mooring rope winder 8 of the floating body B is used to wind and unwind the mooring rope 9 at the same time, and at the same time, before and after, The air tank 3 divided into left and right and up and down is operated by pouring water and draining water. The level of the floating body B is maintained horizontal by adjusting the amount of water injection in the air tank 3 near the stern. The up, down, left and right rudder 4 on the outside of the stern always causes the intake 1 of the bow to face the ocean current. Further, while the floating body B is in operation, the operating states of the floating body B, the water turbine 6, the generator C, etc. are grasped and automatically adjusted, and further, the state of the ocean current around the floating body B is grasped, and the depth of the power generation efficiency is optimized. The floating body B is equipped with a computer for automatically adjusting the diving depth of the floating body B. The status of Floating Body B can be checked and remotely adjusted from a remote ground station.

In the floating body B shown in FIGS. 1 to 4, an intake port 1 of the conduit A is provided on the entire bow face facing the ocean current, and a drain port 2 is provided on the entire stern face. The cross section of the conduit A perpendicular to the ocean current in the center of the water intake 1 and the water discharge port 2 is a circular cross section of a few tenths of the same cross sectional area of the water intake 1, and the water turbine 6 is attached to the cross section. Hereinafter, the ratio of the cross-sectional area of the conduit A perpendicular to the ocean current at the position of the turbine 6 and the cross-sectional area of the intake 1 will be referred to as the compression ratio.

Most of the sea area with ocean currents has a depth of several hundred meters or more. When the water depth exceeds several hundred meters, the buoyancy of the floating body B becomes unstable due to the weight of the mooring line 9 in the sea. In order to reduce the weight of the mooring cable 9,
Attach it to mooring line 9 from the bottom of the sea about 0 m. Intermediate buoyancy body D
Has buoyancy corresponding to the weight of the mooring line 9 from the intermediate buoyancy body D to the anchor 10 in the sea. For example, as shown in FIGS.
Be stable in the ocean current with little fluid resistance. The intermediate buoyant body D makes the mooring area of the floating body B wider.

[0007]

[Operation] Regarding the operation of the floating body B, the same flow velocity (2 m / se
In the current of c), the cross-sectional area (10
An explanation will be given in the following comparison of the following three (a), (b) and (c) using the water turbine 6 (diameter 3.57 m) of m ² ). (See FIG. 8) Hereinafter, for convenience of explanation, specific gravity of seawater =
1 is rounded off as appropriate.

When a water wheel or propeller is directly placed in the ocean current of (a). The theoretical output is calculated as follows. Q = 1/2 · S · Vo ³ · Cp where: Q: theoretical output (kW) S: cross-sectional area perpendicular to the ocean current at the position of the turbine (m ² ) Vo: ocean current velocity (m / s) Cp: Betz's limit value The Betz's limit value is the ratio of conversion of ocean current energy passing through a cross section perpendicular to the ocean current into rotational energy of the turbine when a turbine with a conversion efficiency of 100% is placed directly in the ocean current. It is said to be / 27. Now, if S = 10 m ² Vo = 2 m / s Cp = 16/27 is set, the theoretical output becomes Q = 23.7 kW. The maximum output is the theoretical output multiplied by the conversion efficiency of the turbine and generator.

A case where a water wheel is placed in the cylindrical conduit (b). The theoretical output is calculated as follows. Q = 1/2 · S · Vo ³ where: Q: theoretical output (kW) S: cross-sectional area perpendicular to the ocean current at the position of the turbine (m ² ) Vo: ocean current velocity (m / s) Betz's limit value Is extremely close to 1 and can be ignored. Now, as in (a), if S = 10 m ² Vo = 2 m / s is set, the theoretical output becomes Q = 40 kW. The maximum output is the theoretical output multiplied by the conversion efficiency of the turbine and generator.

(C) Floating body B having a conduit A with a compression ratio of 30
If you put a water wheel 6 inside. The theoretical output is calculated as follows. ^{Q = 1/2 · S ·} V 3 V = t · Vo So = t · S Therefore ^{Q = 1/2 · S (} t · Vo) 3 Q = 1/2 · S · t 3 Vo 3 or Q = 1 / 2 · So · t ² · Vo ³ [Note] where: Q: theoretical output (kW) S: cross-sectional area perpendicular to the ocean current at the position of the turbine 6 (m ² ) V: velocity of the ocean current at the position of the turbine 6 (M / s) t: compression ratio Vo: current velocity of ocean current at intake 1 (m / s) Now, as in (a) and (b), S = 10 m ² Vo = 2 m / s Furthermore, t = 30 When set, the theoretical output will be Q = 1,080,000 kW.

However, when the floating body B is located near the sea surface, most of the ocean current that reaches the intake 1 bypasses the outside of the floating body B and flows to the stern, which is very inefficient. However, as the floating body B dives, the rate at which the ocean current that has reached the intake 1 is taken into the conduit A increases. When the floating body B dives to a depth where the center of the rotation axis of the water turbine 6 is equal to the velocity of the flow velocity of the sea current at the position of the water turbine 6, the sea current flowing to the intake 1 is transferred to the inside of the conduit A. Incorporate 100% of the above into the theoretical output.
Velocity head is a concept that appears in Bernoulli's theorem (fluid mechanics) and expresses the velocity of fluid in a conduit by the height of water pressure. The relational expression is as follows. In ^{V = t · Vo H = V} 2/2 · g where, V: flow velocity of ocean current at the position of the water turbine 6 (m / s) t: Compression ratio Vo: flow velocity of ocean current in intake 1 (m / s) H : Velocity head (m) g: Acceleration of gravity Now, setting t = 30 Vo = 2m / s g = 9.8, the velocity head becomes H = 184m. Therefore, the floating body B is submerged so that the center depth of the rotation axis of the water wheel 6 becomes 184 m.

The maximum power is calculated from the theoretical power as follows. P = n · Q where: P: maximum output (kW) n: combined conversion efficiency of turbine 6 and generator C (%) Q: theoretical output (kW) conversion efficiency of turbine 6 and generator C Use what is used. Turbine efficiency is usually 88-91%,
The efficiency of the generator is 97%, and the product of those efficiencies is 85-88.
%. Hereinafter, the synthetic conversion efficiency is calculated at 87%. Now, substituting Q = 1,080,000 kW n = 87%, the maximum output becomes P = 939,600 kW.

In the above description, how the combination of the structure of the floating body B, the shape of the conduit A, and the diving of the floating body B has a great effect in concentrating the diluted ocean current energy per unit area perpendicular to the ocean current. Was understood. The action of the floating body B is
At the output, compared with the case where the turbine is placed in the cylindrical conduit (b), the compression ratio of the conduit A is cubed when the sectional area of the turbine 6 perpendicular to the ocean current is used as a reference. In addition, the compression ratio is squared when the cross-sectional area of the ocean current perpendicular to the ocean current is used as a reference. (

[Note])

[0014]

EXAMPLE Although there is no example in the present invention, a comparison is made between an actual hydroelectric power plant and an implementation plan of a floating body B calculated to have an effect equal to its output.

The hydroelectric power plant of FIG. 9 (a) is the Shiroyama pumped-storage power plant (in operation) of the Sagami River system in Kanagawa prefecture. (B) is an implementation plan. Numerical value announced by the electric power company of the hydraulic power plant in (a) Water consumption: Me = 192m ³ /
s Effective head: He = 153m Maximum output: Pe = 250,000
Numerical value set for the implementation plan of 0 kW (b) Current velocity of ocean current: Vo = 1.5 m / s Cross-sectional area perpendicular to the ocean current at intake 1: So = 128 m ² Compression ratio: t = 36.5 or less, and (a) We will compare and examine the main specifications of (b).

The flow velocity of the water flow at the position of the water wheel is calculated as follows. In the case of (a). Here, Ve: Flow velocity of the water flow at the position of the water wheel (m / s) g: Acceleration of gravity He: Effective head (m) Now, substituting g = 9.8 He = 153m, the position of the water wheel at (a) The flow velocity of the water stream in Ve is 54.8 m / s (b). V = tVo Here, V: sea current flow velocity at the position of the water wheel 6 (m / s) t: compression ratio Vo: sea current flow velocity at the intake 1 (m / s) Now, t = 36.5 Vo = Substituting 1.5 m / s, the flow velocity of the ocean current at the position of the turbine 6 in (b) is V = 54.8 m / s (a) and the velocity of the water current at the position of the turbine in (b) is the same.

The flow rate at the position of the turbine is calculated as follows. In the case of (a). The amount of water used announced is Me = 192 m ³ / s (b). S = So / t M = V · S where S: sectional area perpendicular to the ocean current at the position of the turbine 6 (m ² ) So: sectional area perpendicular to the ocean current at the intake 1 (m ² ) t: compression ratio M: Flow rate of ocean current at position of turbine 6 (m ³ / s) V: Velocity of ocean current at position of turbine 6 (m / s) Now, So = 128 m ² t = 36.5 V = 54.8 m / s By substituting, the flow rate at the position of the turbine 6 in (b) becomes M = 192 m ³ / s. The published water consumption in (a) and the flow rate of the ocean current at the position of the water turbine 6 in (b) match.

The effective head of (a) and the velocity head of the flow velocity of the ocean current at the position of the water wheel 6 of (b) are calculated as follows. In the case of (a). The announced effective head is for He = 153m (b). H = V ² / 2g where, H: velocity of the ocean current velocity at the position of the turbine 6 (m) V: velocity of ocean current at the position of the turbine 6 (m / s) g: acceleration of gravity Now V = 54 Substituting .8 m / s g = 9.8, the velocity head of the current velocity of the ocean current at the position of the turbine 6 in (b) becomes H = 153 m. The effective head of (a) and the velocity head of the current velocity of the ocean current at the position of the water turbine 6 of (b) match.

The theoretical output is calculated as follows. In the case of (a). Qe = g · He · Me Here, Qe: theoretical output (kW) g: acceleration of gravity He: effective head Me: amount of water used Now, substituting g = 9.8 He = 153 m Me = 192 m ³ / s ( The theoretical output of b) is Qe = 288,000 kW. In the case of (b). Q = 1/2 · So · t ² · Vo ³ where Q: theoretical output (kW) So: cross-sectional area perpendicular to the ocean current at intake 1 (m ² ) t: compression ratio Vo: ocean current at intake 1 Flow velocity (m / s) Now, substituting So = 128 m ² t = 36.5 Vo = 1.5 m / s, the theoretical output of (b) becomes Q = 288,000 kW. (A) and (b)
The theoretical output of is in agreement.

The maximum power is calculated as follows. In the case of (a). Maximum output power Pe = 250,000 kW (b). P = n · Q where: P: maximum output (kW) n: combined conversion efficiency of turbine 6 and generator C (%) Q: theoretical output (kW) Now, n = 87% Q = 288,000 kW substituted Then, the maximum output of (B) is P = 250,000 kW (A) and the maximum output of (B) agree. In the above explanation, it became clear how the ocean current power generation submersible is embodied in comparison with hydroelectric power generation.

[0021]

Since the present invention is configured as described above, it has the following effects.

The resources of the floating body B and the ocean current energy are almost infinite. For example, Kuroshio is 1,500k from Okinawa to Boso Peninsula
m, width 100-200 km, depth 1,000 m, flowing in the center, width 60-100 km, depth 20
There is a flow velocity of 1 to 1.5 m / s at 0 m, and the flow velocity gradually decreases from the central portion to the peripheral portion and at a depth of 200 m or more. The total flow of this Kuroshio is 60,000,000 m ³ / s
Is said. Its annual total discharge is 3 of the annual rainfall of the whole country.
It is more than 000 times. 10% of national rainfall for hydropower
However, the potential energy due to the head of rainwater flowing through the river is only used once from upstream to downstream. On the other hand, ocean current energy can be used any number of times from upstream to downstream. Even thermal power generation, which has a low utilization efficiency, accounts for 20% of the total electricity demand in Japan. Understand how magnificent ocean current energy is.

High-output power generation is possible with low-speed (0.5 m / s or less) ocean current. 200,000 in the ocean current with a flow rate of 0.25 m / s as seen in (a) of Table 1.
Power generation of kW or more is possible. In the conventional proposal of ocean current power generation, high current (1 m / s or more) ocean current was sought in order to obtain high output, and it was limited to the Kuroshio Current and Gulf of Mexico current.
When the ocean current is s or less, the floating body B can be moored in a wide area of many ocean currents in the world. The table (b) is comparable to the present thermal power generation. Also, as shown in the same table (c), ultra high output type is considered in the calculation, but the turbine 6 and the generator C
We have to wait for the development of peripheral technologies such as.

In the low-speed ocean current, the drag force (fluid drag force) due to the flow applied to the floating body B is small. More conveniently, the lower the flow velocity of the ocean current is, the less the fluid drag force applied to the floating body B is. The fluid drag is proportional to the square of the current velocity of the ocean current, and is proportional to the cross-sectional area (projected area viewed from the upstream of the ocean current) perpendicular to the ocean current. Therefore, in the conventional proposal, the power generation system is generated in a high-speed (1 m / s or more) ocean current. Considering the enormous fluid drag force when attempting to moor or install the above structure, it also contributed to the failure of the proposal. On the other hand, for example, in the same table (c), the fluid drag force is 31 tons. Multiplying the safety factor, the weight of the mooring device should be 100 tons.

Tidal currents and rivers are also available. Even in a sea area with a water depth of less than 100 m, such as in the case of a tidal current or the mouth of a big river, the compression ratio can be reduced. However, in tidal current, there are four commutations a day, and the operation of floating body B is 10 a day.
Although it is only time, changes in flow velocity can be predicted with certainty. It also has the advantage of being close to land. There is a problem of quicksand in rivers.

There is no pollution. Floating body B is installed in a water area that is almost negligible when viewed from the vast ocean, with a depth of 1
It is under the sea over 00m. Also, there are no emissions. Therefore, no pollution is considered. It is completely free from stormy weather and can be operated stably for a long time. In addition, it does not hinder ships sailing near the sea.

Compared to the present large-capacity power generation, the initial investment is small and it is economical. If a three-dimensional survey of ocean currents spreads, the development of floating body B, turbine 6 and generator C progresses, and standardized products can be created depending on the velocity of ocean currents and the water depth of the installation area, it will be possible to significantly reduce costs by mass production. You can
For large-capacity power generation, disassembly and maintenance is required once a year, and the annual operation rate is 75% after three months of suspension of operation. In the case of the floating body B, the floating body B of the same standard is replaced once a year. The annual operating rate is close to 100%. Floating body B is inevitable from damage due to rust, electrolytic corrosion, cavitation, and ship bottom fouling organisms, like a general ship, but can be repaired once a year.

[Brief description of drawings]

FIG. 1 is a perspective view of the overall configuration of an ocean current power generation submersible.

FIG. 2 is a side view of a floating body.

FIG. 3 is a plan view of a floating body.

FIG. 4 is a front view of a floating body.

FIG. 5 is a side view of an intermediate buoyancy body.

FIG. 6 is a plan view of an intermediate buoyancy body.

FIG. 7 is a front view of an intermediate buoyancy body.

FIG. 8 is a diagram illustrating the operation of a floating body.

FIG. 9 is a comparison diagram of a hydroelectric power plant and an implementation plan of a ocean current power generation submarine.

[Explanation of symbols]

 A conduit B Floating body C Generator D Intermediate buoyancy body 1 Intake port 2 Drainage port 3 Air tank 4 Directional rudder 5 Hatch 6 Turbine 7 Seabed transmission line 8 Mooring line winder 9 Mooring line 10 Anchor S Cross section perpendicular to the ocean current A section perpendicular to the current at the So intake

Claims (2)

[Claims] 1. A floating body B (ocean current power generation submersible) having a conduit A and a generator C facing the flow, as shown in FIG. 1, on the surface of the ocean current, tidal current, or river where the flow velocity and direction are stable. ) Is moored from the bow by the mooring line 9 and the anchor 10 and is dived. The ocean current energy flowing in the conduit A is converted into electric energy by the water turbine 6 and the generator C, and the electricity is transmitted to the land by the undersea power transmission line 7. As shown in FIGS. 2 to 4, the entire surface of the bow of the floating body B is used as the water intake port 1, and the cross-sectional area of the conduit A connecting the water intake port 1 and the stern water discharge port 2 perpendicular to the ocean current is It is compressed to several tenths of the same cross-sectional area of to make a circle. The water wheel 6 is installed there. The seawater flow velocity at the position of the water wheel 6 is accelerated to several tens of times the seawater flow velocity at the intake 1. However, when the floating body B is near the sea surface, the seawater that has reached the intake port 1 does not get sucked into the conduit A and bypasses the outside of the floating body B and flows to the stern. The floating body B reaches the intake 1 by submersing the floating body B to a depth such that the center of the rotation axis of the turbine 6 of the floating body B is equal to the height of the velocity head (later described) of the velocity of the ocean current at the position of the turbine 6. 100% of the ocean current can be taken into the conduit A. The present invention utilizes the infinite resource called ocean current energy by combining the structure of the floating body B, the shape of the conduit A, and the diving of the floating body B, and obtains a large amount of electricity that is economically viable and economical without pollution. Is. 2. A floating body B in a sea area having a depth of several hundred meters or more.
In order to reduce the weight of the mooring line 9 in the sea when mooring, the intermediate buoyancy body D shown in FIGS.
Attach it to mooring line 9 from the bottom of the sea about 0 m. Intermediate buoyancy body D
Has a buoyancy equal to the weight of the mooring line 9 from the intermediate buoyancy body D to the anchor 10 in the sea, and by mounting the buoyancy body B, the installable sea area becomes wider.