An articulated raft array wave energy absorption system

Abstract

The present invention belongs to the technical field of ocean energy utilization and renewable energy power generation, and particularly relates to an articulated raft array wave energy absorption system, the main structure of which includes an underwater submersible, a support structure, a power generation platform, an articulated raft, and a plurality of hydraulic cylinders. The underwater submersible provides stable support for the entire system; the power generation platform is connected to the underwater submersible through the support structure as an integral structure; the articulated raft is connected to the support structure through four sets of sliding sleeves; the articulated raft floats on the wave surface and bends with the movement of the waves, thereby converting the wave energy of the wave surface contacted by the articulated raft into the mechanical energy of the raft, and then extracting the mechanical energy of the articulated raft movement through a plurality of hydraulic cylinders, converting it into hydraulic energy through hydraulic oil pipes, and finally converting the hydraulic energy into electrical energy through a plurality of power generation and energy storage units, electrical energy processing units, etc. arranged on the power generation platform, and outputting it through external transmission lines.

Description

Technical Field

[0001] The invention belongs to the technical field of ocean energy utilization and renewable energy power generation, and in particular relates to an articulated floating raft array type wave energy absorption system. Background Art

[0002] Wave energy is a very promising clean and renewable energy source with the advantages of good energy quality, large storage capacity and wide distribution. Its development and utilization is of great significance to promoting sustainable development and the development of marine resources. In China, the development and utilization of wave energy has been included in the national energy development strategy and has broad development prospects.

[0003] Existing offshore wave energy utilization technologies can be divided into two categories: point absorption and line absorption. Point absorption wave energy conversion devices mainly use the displacement or relative displacement change generated by the heaving motion of the floating body in the waves, and convert the mechanical energy of the floating body movement into hydraulic energy or electromagnetic energy through PTO (Power Take-off) damping, and then pass through energy storage and transmission units such as accumulators to finally drive the generator to generate electricity, or produce fresh water or ice through other equipment. This type of device mainly includes specific types such as oscillating float type and oscillating water column type. Line absorption wave energy conversion devices can absorb wave energy at a certain distance along the wave propagation line, such as the famous British "Pelamis" type device. The device consists of multiple groups of articulated rafts. The rafts move under the excitation of waves, and the (angular) displacement between adjacent rafts changes. The mechanical energy of the raft movement is extracted through the PTO damping mechanism installed between adjacent rafts. In addition, the wave-riding device that reasonably utilizes the coastal terrain, converts the kinetic energy of the waves into potential energy, and then generates electricity using the sea water head pressure difference is also an important type.

[0004] The above-mentioned wave energy conversion device has a good energy conversion effect, but because it can only absorb wave energy within a relatively limited wave crest line width range such as points or lines, generally, a better wave energy conversion effect can be obtained only when the wave height is relatively large; compared with the wave conditions in Europe, North America and other sea areas (wave height is 2.0m-6.0m), the wave height in most of the sea areas near the coast of China is relatively small (0.5m-3.0m), and the wave energy flux density is relatively low, making it difficult to directly utilize the existing wave energy conversion devices with high efficiency, and the comprehensive utilization cost is high, and even causing some scattered and low-grade wave energy resources to be wasted. Therefore, it is necessary to solve the problem of the small wave crest line width of wave energy absorption by the existing devices through a certain system, so as to utilize wave energy more economically, fully and efficiently. Summary of the invention

[0005] The main purpose of the present invention is to provide an articulated raft array wave energy absorption system, which has a simple overall structure and can improve the efficiency of wave energy utilization, so as to solve the problem of scattered and low-grade wave energy resources that cannot be utilized or are insufficiently utilized due to the small width of the wave crest line of wave energy absorption in existing wave energy conversion devices.

[0006] The specific technical solution adopted by the present invention is as follows:

[0007] An articulated raft array wave energy absorption system is used to maximize the absorption and utilization of dispersed, low-grade wave energy with small wave heights. The system is an independent offshore power generation unit, and the main structure includes an underwater submersible, a supporting structure, an offshore power generation platform, an articulated raft and several hydraulic cylinders. Among them, the underwater submersible is a rectangular floating structure with a certain mass and a large volume, which is submerged in the sea water and provides stable support for the entire system; the offshore power generation platform is a flat structure, on which the power generation unit is arranged to convert energy, and is connected to the underwater submersible as an integral structure through the support structure, and the articulated raft can only bend along the wave propagation direction and remain unchanged in the direction perpendicular to the wave propagation direction; the articulated raft is connected to the support structure through the four sets of sliding sleeves; the articulated raft floats on the wave surface and bends with the wave movement, thereby converting the wave energy of the wave surface contacted by the articulated raft into the mechanical energy of the raft, and then extracting the mechanical energy of the articulated raft movement through a number of hydraulic cylinders, converting it into hydraulic energy through hydraulic oil pipes, and finally converting the hydraulic energy into electrical energy through a number of power generation and energy storage units, power processing units, etc. arranged on the offshore power generation platform, and outputting it through transmission lines.

[0008] The articulated raft has a certain mass and thickness, and is formed by articulating multiple groups of narrow slender rafts along the wave propagation direction, and can only bend along the wave propagation direction, but remain unchanged in the direction perpendicular to the wave propagation direction. Preferably, the draft of the articulated raft in a static water state is about 60% of its thickness; the length of the articulated raft in a bent state is between 1 and 2 wavelengths of the incident wave.

[0009] The articulated raft is connected to the supporting structure through four sets of sliding sleeves. The articulated raft slides up and down on the supporting structure within a certain range through the sliding sleeves to adapt to waves and the draft of the system, so that the articulated raft floats on the wave surface at all times.

[0010] A further improvement of the present invention is that the displacement of the underwater submersible body is slightly less than the total mass of other structures of the system except the articulated raft in the present invention. The underwater submersible body is submerged in the water to a certain depth, specifically, the depth of the upper edge of the underwater submersible body from the water surface is 1 / 3 of the wavelength of the incident wave.

[0011] According to a further improvement of the present invention, the hydraulic cylinders are arranged in a uniform array on the articulated raft along the bending direction of the articulated raft, and the spacing between adjacent hydraulic cylinders is 1 / 2 of the wavelength of the incident wave.

[0012] The power generation and energy storage units, power processing units, etc. are installed on the power generation platform. Power generation units such as hydraulic motors and generators convert hydraulic energy into alternating current, and output direct current after floating charging a number of parallel-connected batteries (groups). The output direct current is further processed and then transmitted to the shore or power equipment through transmission lines.

[0013] The system of the present invention also includes an anchor system, one end of which is fixed to the seabed and the other end is connected to the underwater submersible, which is used to fix the entire system at a specified sea surface position and make the bending direction of the system's articulated raft consistent with the wave propagation direction under the action of marine environmental loads such as wind, waves and currents.

[0014] The present invention proposes an articulated raft array wave energy absorption system. Under the influence of marine environmental loads such as wind, waves and currents at sea and the anchor system, the system automatically adjusts its direction at sea, and finally the bending direction of the articulated raft is consistent with the wave propagation direction.

[0015] Compared with the prior art, the present invention has a larger crest line width occupied by the raft without increasing the cost of intermediate energy conversion equipment, and the raft captures more wave energy. Therefore, under the same wave conditions, the articulated raft of the present invention has a greater force on the hydraulic cylinder, thereby being able to effectively and fully utilize the dispersed, low-grade wave energy with a low energy flow density.

[0016] Beneficial effects of the present invention: The present invention improves the economy and efficiency of wave energy conversion, and realizes full, economical and efficient utilization of low-grade renewable energy with low resource utilization value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] In the figure, 1-underwater submersible, 2-support structure, 3-articulated raft, 4-hinge between rafts, 5-sliding sleeve, 6-several hydraulic cylinders, 7-hydraulic cylinder-articulated raft hinge, 8-hydraulic cylinder-fixed point of power generation platform, 9-power generation platform, 10-hydraulic oil pipe, 11-power generation and energy storage unit, 12-internal transmission line, 13-electric energy processing unit, 14-external transmission line, 15-anchor, 16-incident wave. DETAILED DESCRIPTION

[0019] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention and do not limit the protection scope of the present invention.

[0020] Example: Figure 1 As shown, an articulated raft array wave energy absorption system, the main structure of which includes an underwater submersible 1, a supporting structure 2, a power generation platform 9, an articulated raft 3 and a plurality of hydraulic cylinders 6.

[0021] The specific working process of the system includes three levels of energy conversion. First, under the action of the incident wave 16, the articulated raft 3 generates periodic bending and undulating motion in the direction perpendicular to the crest line, and the wave energy within the width range b of the crest line of the articulated raft 3 is absorbed by the raft body, that is, the first level of energy conversion - the wave energy within the width range b of the crest line of the articulated raft 3 is converted into the mechanical energy of the bending and undulating motion of the articulated raft 3. Subsequently, the periodic bending and undulating motion of the articulated raft 3 drives the piston rods of the several hydraulic cylinders 6 connected thereto to perform reciprocating motion, that is, the second level of energy conversion - the mechanical energy of the bending and undulating motion of the articulated raft 3 is converted into the hydraulic energy of the several hydraulic cylinders 6. Furthermore, the hydraulic energy of the several hydraulic cylinders 6 is converted into electrical energy through the hydraulic oil pipe 10, and the power generation and energy storage unit 11, the electric energy processing unit 13, etc. arranged on the power generation platform 9, that is, the third level of energy conversion - the hydraulic energy of the several hydraulic cylinders 6 is converted into electrical energy. Finally, the electrical energy is output through the external transmission line 14.

[0022] In this embodiment, the articulated floating raft 3 is a floating raft structure that can only bend in the wave propagation direction. Specifically, it is composed of a plurality of slender raft bodies connected by hinges 4 between the raft bodies. The number of connected slender raft bodies, that is, the length l of the articulated floating raft 3 in the bending state mainly depends on the power P of the incident wave 16 (estimated to be P=0.5bTH 2 , b: crest line width of the articulated floating raft 3, T: wave period, H: wave height), the smaller the power P of the incident wave 16 is, the smaller the length b of the articulated floating raft 3 is. However, in order to make the entire articulated floating raft 3 run stably on the waves, the length l of the articulated floating raft 3 in the bending state should not be less than the length of one wavelength λ (according to the estimation under the linear wave condition, the length l of the articulated floating raft 3 in the bending state ≥ λ = gT 2 / (2π)). Preferably, in order to save costs, the present invention sets the length l of the articulated floating raft in the bending state to 2λ≥l≥λ. In addition, the setting of the width b of the articulated floating raft 3 (i.e., the crest line width of the articulated floating raft 3) mainly considers the power P of the incident wave 16. The smaller the power P, the larger the width b of the articulated floating raft 3.

[0023] The articulated floating raft 3 has a certain thickness and mass to ensure that the raft body has a suitable draft in a static water state so as to effectively convert the incident wave energy into its own mechanical energy. Preferably, according to the results of numerical simulation, the best effect can be achieved when the draft of the articulated floating raft 3 is 60% of its own thickness.

[0024] The function of the underwater submersible 1 is to provide a stable foundation for the entire system described in the present invention. Under normal working conditions, the underwater submersible 1 is submerged at a certain depth d below the water surface. The selection criterion of the depth d is to ensure that the underwater submersible 1 is less affected by the sea surface waves. When the underwater submersible 1 of the system of the present invention is subjected to specific wave influence effect detection under conditions of different depths d, it is found that when the depth d reaches about 1 / 3 of the wavelength λ, the influence of the wave on the underwater submersible is already very weak (about 5% of the fluid force at depth d=0). Considering the factors of system cost saving and convenient maintenance, it is preferred to set the depth d of the upper edge of the underwater submersible 1 submerged underwater to 1 / 3 of the wavelength λ of the incident wave 16.

[0025] In an embodiment of the present invention, the displacement of the underwater submersible 1 is slightly smaller than the total mass of other structures in the system of the present invention except the articulated raft 3, so that the underwater submersible 1 can be stabilized in the sea water at a certain depth under the action of the anchor system 15, and the anchor system 15 will not be subjected to excessive force.

[0026] The plurality of hydraulic cylinders 6 are installed between the articulated raft 3 and the power generation platform 9. Specifically, the piston rod of the hydraulic cylinder 6 is hingedly connected to the articulated raft 3 through the hydraulic cylinder-articulated raft hinge 7, and the cylinder body of the hydraulic cylinder 6 is rigidly connected to the power generation platform 9 through the hydraulic cylinder-power generation platform fixing point 8. In the embodiment of the present invention, in order to make the hydraulic cylinder 6 more convenient and effective in converting wave energy and save costs as much as possible, preferably, the plurality of hydraulic cylinders 6 are evenly arranged along the bending direction of the articulated raft 3, and the spacing between adjacent hydraulic cylinders is 1 / 2 of the wavelength λ of the incident wave 16.

[0027] It should be noted that the specific embodiment of the present invention adopts a hydraulic cylinder as an energy conversion unit, which is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. There is no restriction or fixation on this invention. Other forms of energy conversion units can be selected according to specific circumstances, such as linear motor type, mechanical or piezoelectric energy conversion unit, etc.

[0028] Several power generation and storage units 11, power processing units 13, transmission lines 12 and other power devices are arranged on the power generation platform. This arrangement can effectively prevent the above-mentioned power devices from being corroded by seawater, thereby reducing the system's cost expenditure on insulation, waterproofing, etc., and improving the system's survivability performance.

[0029] In the embodiment of the present invention, the two ends of the anchor cable of the anchor system 15 are respectively connected to the seabed and the front end midpoint of the underwater submersible body 1, and the length and mass of the anchor cable are adjusted according to the depth of the water area and the diving depth d of the underwater submersible body 1. Figure 1Under the combined effects of wind, waves, currents and the anchor system 15, the bending direction of the articulated raft 3 of the entire system provided by the present invention is always consistent with the wave propagation direction, so that the system can capture and convert the wave energy of incident waves 16 from different directions to the maximum extent.

[0030] In a specific embodiment, the size, mass, material, working parameters, etc. of the underwater submersible 1, articulated raft 3, hydraulic cylinder 6, support structure 2, power generation platform 9, etc. used in the present invention can be adjusted according to the wave conditions of the sea area of ​​use. Since the entire device is a semi-submersible structure, it has good adaptability to other sea conditions such as offshore wind, waves, currents, etc.

[0031] Compared with the prior art, the present invention can make full use of dispersed, low energy flow density wave energy, improve the economy and efficiency of wave energy conversion, and realize the full, economical and efficient utilization of low-grade renewable energy with low resource utilization value.

[0032] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An articulated raft array wave energy absorption system, characterized in that: The main structure includes an underwater submersible, a supporting structure, a power generation platform, an articulated raft and a number of hydraulic cylinders. The underwater submersible is a rectangular floating structure with a certain mass and a large volume, which is submerged in the sea water and provides stable support for the entire system. The power generation platform is a flat structure, on which power generation units are arranged for energy conversion, and is connected to the underwater submersible through the supporting structure to form an integral structure. The articulated raft is a flat floating structure floating on the water surface that can be freely bent in the direction of wave propagation, and is used to capture the wave energy of the occupied wave surface. The piston rods and cylinder barrels of the several hydraulic cylinders are respectively connected to the power generation platform and the articulated raft; the hydraulic cylinders are arranged in a uniform array on the articulated raft along the bending direction of the articulated raft, and the spacing between adjacent hydraulic cylinders is 1 / 2 of the wavelength of the incident wave; it also includes a power generation and energy storage unit, and an electric energy processing unit, and both are installed on the power generation platform.

2. The articulated raft array wave energy absorption system according to claim 1, characterized in that: The articulated raft has a certain mass and thickness, and its draft in still water is about 60% of its thickness. The length of the articulated raft in a bent state is between 1 and 2 wavelengths of the incident wave.

3. The articulated raft array wave energy absorption system according to claim 1, characterized in that: The articulated floating raft is formed by articulating a plurality of groups of slender floating rafts with narrow widths along the wave propagation direction, and is bent along the wave propagation direction but remains unchanged in a direction perpendicular to the wave propagation direction.

4. The articulated raft array wave energy absorption system according to claim 1, characterized in that: The articulated raft is connected to the supporting structure through four sets of sliding sleeves. The articulated raft slides up and down on the supporting structure within a certain range through the sliding sleeves to adapt to waves and the draft of the system, so that the articulated raft floats on the wave surface at all times.

5. The articulated raft array wave energy absorption system according to claim 1, characterized in that: The underwater submersible body is submerged in the water to a certain depth, specifically, the depth of the upper edge of the underwater submersible body from the water surface is 1 / 3 of the wavelength of the incident wave.

6. The articulated raft array wave energy absorption system according to claim 1, characterized in that: The displacement of the underwater submersible body is slightly smaller than the total mass of other structures in the system except the articulated raft.

7. The articulated raft array wave energy absorbing system according to any one of claims 1 to 6, characterized in that: The system also includes an anchor system, one end of which is fixed to the seabed and the other end is connected to one end of the underwater submersible body, so as to fix the entire system at a designated sea surface position.

Images