Floating body for photovoltaic power generation system and photovoltaic power generation system

Abstract

The invention provides a floating body for a photovoltaic power generation system and the photovoltaic power generation system. The floating body for a photovoltaic power generation system according to the present invention comprises: an upper structure having a flat-shaped installation part on one surface; a lower structure disposed to correspond to the upper structure and including a hemispherical shape protruding downward; and a fixing part for coupling the upper structure and the lower structure.

Description

Technical Field

[0001] The present invention relates to a floating body for a photovoltaic power generation system and a photovoltaic power generation system. Background Art

[0002] Generally, compared with land or freshwater systems, floating offshore photovoltaic power generation systems are suitable for deep waters, are not affected by the ground, can be moved and reused, are relatively cost-effective, and can be set up quickly, thus having the advantage of relatively low construction costs according to water depth.

[0003] However, different from the freshwater environment, the stability and robustness of offshore photovoltaic power generation systems are greatly related to the sea level of the sea area where they are set up. Therefore, when determining the setting position and direction, it is necessary to further consider wave direction (wave direction), wave height (wave height), and sea tide, etc.

[0004] In particular, due to the large physical energy fluctuations of sea tides generated by tidal phenomena including sea winds such as typhoons, the whole or part of the floating offshore photovoltaic power generation system frequently moves left and right or up and down, increasing the repeated fatigue load on the photovoltaic panel module support structure and the mooring device, resulting in a decrease in the lifespan of the offshore photovoltaic power generation system.

[0005] In addition, the stagnant sea current inside the lower part of the offshore photovoltaic system set in a large area will cause marine pollution.

[0006] In addition, generally, offshore photovoltaic power generation systems use floating bodies based on plastic materials, which not only have concerns about environmental hazards, but also are very vulnerable to corrosion in the seawater environment and are prone to corrosion problems.

[0007] Therefore, a solution is needed to ensure that the floating body has excellent corrosion resistance, durability, and impact resistance to overcome these problems. Summary of the Invention

[0008] Technical Problem to be Solved

[0009] The present invention aims to provide a floating body for a photovoltaic power generation system and a photovoltaic power generation system, which can overcome the corrosion resistance limit and environmental hazards of the floating body in the seawater environment, and increase the penetrating waves passing through the floating body as much as possible, thereby preventing marine pollution caused by the stagnation of sea currents below the photovoltaic power generation system in advance.

[0010] Technical Solution

[0011] The floating body for a photovoltaic power generation system according to an embodiment of the present invention may include: an upper structure including a flat-shaped setting part on one surface thereof; a lower structure configured to correspond to the upper structure and including a hemispherical shape protruding in a direction away from the setting part; and a fixing part for combining the upper structure and the lower structure.

[0012] The upper structure can have one of the shapes of a hemispherical shape, a semi-conical shape, and a semi-elliptical shape.

[0013] It may further include: an upper flange portion that extends in the outer direction of the upper structure; and a lower flange portion that is configured to correspond to the upper flange portion and extends in the outer direction of the lower structure.

[0014] The fixing portion can use screws or welding to join the upper structure and the lower structure or use bolts or welding to join the upper flange portion and the lower flange portion.

[0015] The upper flange portion may include a first upper groove, and the lower flange portion may include a first lower groove configured to correspond to the first upper groove.

[0016] A first non-metallic airtight gasket may be disposed between the first upper groove and the first lower groove.

[0017] The upper flange portion may include at least one second upper groove outside the first upper groove, and the lower flange portion may include at least one second lower groove configured to correspond to the second upper groove.

[0018] A second non-metallic airtight gasket may be disposed between the second upper groove and the second lower groove.

[0019] The upper flange portion may include an upper flat portion between the first upper groove and the second upper groove, and the lower flange portion may include a lower flat portion configured to correspond to the upper flat portion between the first lower groove and the second lower groove.

[0020] A third non-metallic airtight gasket may be disposed between the upper flat portion and the lower flat portion.

[0021] The materials of the first non-metallic airtight gasket, the second non-metallic airtight gasket, and the third non-metallic airtight gasket may be silica gel.

[0022] A connecting portion may be provided on the setting portion for connecting one floating body and another adjacent floating body.

[0023] The setting portion may include a communicating portion communicating with the internal hollow portion of the upper structure, and a positive pressure applying device for applying positive pressure to the inside of the upper structure may be provided in the communicating portion.

[0024] The connecting portion may include: a first setting hole for setting the positive pressure applying device; and a socket portion for setting a connecting frame for connecting with an adjacent floating body for a photovoltaic power generation system.

[0025] A plurality of socket portions may be arranged at a set interval based on the connecting portion.

[0026] The cross-sectional shape of the socket portion may have a trapezoidal shape.

[0027] At least one roller part for supporting a mooring device cable passing through the socket part may be provided inside the socket part.

[0028] The positive pressure applying device may include: an injection pipe connected to the connection part for injecting positive pressure gas; a valve cover provided on the injection pipe for closing the injection pipe; and a support body coupled to the installation part for supporting the injection pipe.

[0029] Air or carbon dioxide (CO 2 ) gas may be injected into the injection pipe at a pressure of a set magnitude.

[0030] The upper structure and the lower structure may be made of a metal material.

[0031] The metal material may be any one material selected from austenitic, ferritic, and duplex stainless steels.

[0032] The upper structure and the lower structure may include recesses on the surface.

[0033] The height of the upper structure and the lower structure may be set to be less than the radius of the upper structure and the lower structure.

[0034] The socket part may be made of the same metal material as the upper structure and the lower structure.

[0035] In addition, a photovoltaic power generation system according to an embodiment of the present invention may include the floating body described above.

[0036] Advantageous Effects

[0037] According to an embodiment of the present invention, a metal material with excellent corrosion resistance is used, and a spherical floating body shape with excellent durability, impact resistance, and airtightness can be provided regardless of the material of the floating body and the direction of sea breeze and wave movement.

[0038] Therefore, it is possible to overcome the environmental hazard problem of a plastic-based floating photovoltaic power generation system and the corrosion resistance limit in a seawater environment. Since the penetration waves through the floating body are increased as much as possible, it is possible to prevent marine pollution caused by stagnant sea currents inside the lower part of a large-area offshore photovoltaic power generation system. Brief Description of the Drawings

[0039] Figure 1 is a schematic combined perspective view of a floating body for a photovoltaic power generation system according to an embodiment of the present invention.

[0040] Figure 2 is a schematic partial exploded perspective view of a floating body for a photovoltaic power generation system according to an embodiment of the present invention.

[0041] Figure 3 is Figure 1Partial cross-sectional view of part A, (a) showing the combined state of the upper flange part and the lower flange part according to the first embodiment, (b) showing the combined state of the upper flange part and the lower flange part according to the first embodiment.

[0042] Figure 4 It is a schematic perspective view of a connecting part of a floating body for a photovoltaic power generation system according to an embodiment of the present invention.

[0043] Figure 5 It is a cross-sectional view of a connecting part of a floating body for a photovoltaic power generation system according to an embodiment of the present invention, (a) showing a trapezoidal cross-sectional shape, (b) showing a rectangular cross-sectional shape, and (c) showing a circular cross-sectional shape.

[0044] Figure 6 It is a schematic perspective view of a positive pressure applying device for a floating body of a photovoltaic power generation system according to an embodiment of the present invention.

[0045] Figure 7 It is a schematic partial exploded perspective view of a floating body for a photovoltaic power generation system according to another embodiment of the present invention.

[0046] Figure 8 It is a comparison chart of the number of floating bodies with respect to the settlement volume (settlement rate) of the floating body for the comparative example and the embodiment of the present invention. Detailed implementation manners

[0047] Hereinafter, embodiments of the present invention will be described with reference to the drawings so that those of ordinary skill in the art to which the present invention pertains can easily implement the present invention. Those of ordinary skill in the art to which the present invention pertains should understand that, without departing from the concept and scope of the present invention, the following embodiments can be implemented in various different ways. The same reference numerals are used as much as possible in the drawings to indicate the same or similar parts.

[0048] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. Unless otherwise clearly indicated to the contrary in the context, the singular forms used herein are also intended to include the plural forms. It should also be understood that the term "comprising" can specifically refer to a certain characteristic, field, integer, step, action, element, and / or component, and does not exclude the existence or addition of other characteristics, fields, integers, steps, actions, elements, components, and / or groups.

[0049] The meanings of all terms used below (including technical terms and scientific terms) are the same as those generally understood by those of ordinary skill in the art to which the present invention pertains. For terms defined in a dictionary, they should be interpreted as having a meaning consistent with the relevant technical literature and the content disclosed herein, and should not be interpreted in an idealized or overly formal sense.

[0050] Figure 1 Schematic combined perspective view of a floating body for a photovoltaic power generation system according to an embodiment of the present invention Figure 2 Schematic partial exploded perspective view of a floating body for a photovoltaic power generation system according to an embodiment of the present invention

[0051] Figure 3 is Figure 1 A partial cross-sectional view of (a) shows the combined state of the upper flange portion and the lower flange portion according to the first embodiment, and (b) shows the combined state of the upper flange portion and the lower flange portion according to the first embodiment

[0052] Figure 4 Schematic perspective view of the connecting portion of a floating body for a photovoltaic power generation system according to an embodiment of the present invention Figure 5 Cross-sectional view of the connecting portion of a floating body for a photovoltaic power generation system according to an embodiment of the present invention, (a) shows a trapezoidal cross-sectional shape, (b) shows a rectangular cross-sectional shape, and (c) shows a circular cross-sectional shape

[0053] Figure 6 Schematic perspective view of the positive pressure applying device of a floating body for a photovoltaic power generation system according to an embodiment of the present invention Figure 7 Schematic partial exploded perspective view of a floating body for a photovoltaic power generation system according to another embodiment of the present invention

[0054] Referring to Figures 1 to 7 , the floating body 10 for a photovoltaic power generation system according to an embodiment of the present invention may include an upper structure 100, a lower structure 200, and a fixing portion 300

[0055] The upper structure 100 may include a flat setting portion 101 on one side, such as the upper end face

[0056] In addition, the lower structure 200 may be configured to correspond to the upper structure 100 and include a hemispherical shape protruding downward ( Figure 1 in the Y direction) that is, in the direction away from the setting portion 101

[0057] The fixing portion 300 may fixedly combine the upper structure 100 and the lower structure 200

[0058] In addition, the setting portion 101 may refer to a plane obtained by cutting the upper end portion (top) of the upper structure 100 with a plane parallel to the lower end face of the upper structure 100

[0059] The upper structure 100 may have one shape selected from a hemispherical shape, a semi-conical shape, a semi-elliptical shape, etc. protruding upward ( Figure 1 in the Y direction) that is, in the direction away from the lower structure 200, so that water (seawater) under the action of an external force can pass through smoothly

[0060] The lower structure 200 includes a hemispherical shape protruding downward so that water (seawater) under external force can pass smoothly, and can have buoyancy that can float on the water surface, enabling the upper structure 100 disposed on the upper part of the lower structure 200 to float on the water surface.

[0061] The floating body 10 for a photovoltaic power generation system can have a spherical shape as a whole through the upper structure 100 and the lower structure 200, so that the resistance to external forces such as sea wind load and wave load is small on the sea, and the incident waves form streamlines (penetrating waves) along the surface of the floating body, so that they can naturally propagate to the inner side of the floating offshore photovoltaic power generation system.

[0062] In addition, the upper structure 100 and the lower structure 200 can be made of a metal material or the like to have excellent corrosion resistance, such as strong resistance to surface corrosion and crevice corrosion of the immersed part of the floating body.

[0063] As such a metal material, any material selected from austenite, ferrite, duplex stainless steel, etc. with high corrosion resistance can be used.

[0064] The upper structure 100 and the lower structure 200 of the floating body 10 for a photovoltaic power generation system can be made by metal stamping processing or the like that plastically deforms a metal disc.

[0065] Considering the cold rolling processability including the metal elongation rate, the height Rb1 of the upper structure 100 and the height Rb2 of the lower structure 200 can be set to be less than the radius Ra of the upper structure 100 and the lower structure 200.

[0066] For the lower end portion 100-1 of the upper structure 100 and the upper end portion 200-1 of the lower structure 200, in order to prevent cracks from occurring in the portion where the shape changes sharply during the processing, considering the cold rolling processability including the metal elongation rate, they can respectively have rounded portions R2 formed by rounding processing.

[0067] In addition, the floating body 10 for a photovoltaic power generation system can include: an upper flange portion 110 that extends in the outer direction of the upper structure 100; a lower flange portion 210 that is arranged corresponding to the upper flange portion 110 and extends in the outer direction of the lower structure 200.

[0068] The fixing portion 300 can combine the upper structure 100 and the lower structure 200 or combine the upper flange portion 110 and the lower flange portion 210.

[0069] The upper flange portion 110 can extend from the outer peripheral surface of the lower end portion of the upper structure 100 in the outer direction (i.e., the radial direction).

[0070] In addition, the lower flange portion 210 can extend outward (i.e., in the radial direction) from the outer peripheral surface of the upper end portion of the lower structure 200.

[0071] The fixing portion 300 can combine an upper thread (not shown in the figure) disposed inside or outside the lower end portion of the upper structure 100 and a lower thread (not shown in the figure) corresponding to the upper thread inside or outside the upper end portion of the lower structure 200, or fix the upper structure 100 and the lower structure 200 by welding.

[0072] In addition, the fixing portion 300 can include a connecting bolt 310 for connecting the upper flange portion 110 and the lower flange portion 210, a nut 320 for connecting to the connecting bolt 310, and the like.

[0073] For the connecting bolt 310, a plurality of them are combined at set intervals on the upper flange portion 110 and the lower flange portion 210 to ensure a firm combination between the upper flange portion 110 and the lower flange portion 210.

[0074] In addition, the upper flange portion 110 can have an upper coupling hole 111 for inserting the connecting bolt 310, and the lower flange portion 210 can have a lower coupling hole 211 configured to correspond to the upper coupling hole 111 and for inserting the connecting bolt 310.

[0075] In addition, the upper coupling holes 111 can be arranged at set intervals along the circumferential surface of the upper flange portion 110 on a radius R5 (where R5 > Ra) having a set size with the center O1 of the lower end portion of the upper structure 100 as the center.

[0076] The lower coupling holes 211 can be arranged at set intervals along the circumferential surface of the lower flange portion 210 on a radius R5 (where R5 > Ra) having a set size with the center O2 of the upper end portion of the lower structure 200 as the center.

[0077] In addition, the fixing portion 300 can also be fixed by welding the outer side surfaces of the upper flange portion 110 and the lower flange portion 210 without using the connecting bolt 310 and the nut 320.

[0078] The upper flange portion 110 can include a first upper groove 113 protruding upward, and the lower flange portion 210 can include a first lower groove 213 recessed downward and configured to correspond to the first upper groove 113.

[0079] A first non-metallic airtight gasket 400 can be arranged between the first upper groove 113 and the first lower groove 213.

[0080] In addition, the upper flange portion 110 protrudes upward and can include at least one second upper groove 115 outside the first upper groove 113.

[0081] The lower flange portion 210 may include a second lower groove 215 that is recessed downward and configured to correspond to the second upper groove 115.

[0082] A second non-metallic airtight gasket 410 may be disposed between the second upper groove 115 and the second lower groove 215.

[0083] In addition, the first upper groove 113 and the second upper groove 115 may be arranged at a set interval along the circumferential surface of the upper flange portion 110 on a circle with a set radius R6 centered on the central portion O1 of the lower end of the upper structure 100 (where R5 > R6 > Ra).

[0084] The first lower groove 213 and the second lower groove 215 may be arranged at a set interval along the circumferential surface of the lower flange portion 210 on a circle with a set radius R6 centered on the central portion O2 of the upper end of the lower structure 200 (where R5 > R6 > Ra).

[0085] Furthermore, the upper flange portion 110 may include an upper flat portion 117 between the first upper groove 113 and the second upper groove 115, and the lower flange portion 210 may include a lower flat portion 217 configured to correspond to the upper flat portion 117 between the first lower groove 213 and the second lower groove 215.

[0086] Here, the upper flat portion 117 or the lower flat portion 217 is a region with a relatively smaller curvature than the first upper groove 113 or the second upper groove 115, and does not mean completely flat.

[0087] A third non-metallic airtight gasket 420 may be disposed between the upper flat portion 117 and the lower flat portion 217.

[0088] In addition, the thickness (2t + h) of the third non-metallic airtight gasket 420 may be set to be thicker than the sum of the thicknesses 2t of the upper flange portion 110 and the lower flange portion 210 and thinner than the thickness of the first non-metallic airtight gasket 400.

[0089] The materials of the first non-metallic airtight gasket 400, the second non-metallic airtight gasket 410, and the third non-metallic airtight gasket 420 may be silicone rubber or the like.

[0090] In addition, a connecting portion 500 may be provided on the setting portion 101 for connecting one floating body 10 and another adjacent floating body 10.

[0091] The upper structure 100 may include a hollow portion (not shown in the figure) with a hollow interior, and the lower structure 200 may include a hollow portion (not shown in the figure) with a hollow interior.

[0092] In addition, low-density filling materials such as styrofoam can be inserted into the hollow parts (not shown in the figure) of the upper structure 100 and the lower structure 200, and gases such as oxygen or carbon dioxide can be injected into the gaps between the filling materials, so that the upper structure 100 and the lower structure 200 can float on the water surface.

[0093] The central part of the setting part 101 includes a communication part 103 communicating with the internal hollow part of the upper structure 100, and a positive pressure applying device 600 for applying positive pressure to the inside of the upper structure 100 can be arranged in the communication part 103.

[0094] The setting part 101 has a radius R3 of a set size centered on the center of the communication part 103, and the communication part 103 can have a radius R4 of a set size.

[0095] The connecting part 500 may include: a first setting hole 510 arranged at the lower end of the connecting part 500 for arranging the positive pressure applying device 600; a socket part 520 for inserting a connecting frame 530, and the connecting frame 530 is used for connecting adjacent floating bodies 10 for photovoltaic power generation systems.

[0096] A plurality of socket parts 520 can be arranged at a set interval based on the center of the connecting part 500. Figure 4 In the middle, 4 socket parts 520 are arranged at intervals of 90 degrees centered on the center of the connecting part 500, but this is not limited thereto. Of course, according to needs, less than 4 or more than 4 can be arranged.

[0097] In addition, the connecting part 500 may include a second setting hole 511 arranged at the upper end of the connecting part 500 and communicating with the first setting hole 510 for inserting the positive pressure applying device 600.

[0098] The first setting hole 510 may have a diameter smaller than that of the second setting hole 511, so that the positive pressure applying device 600 can easily apply positive pressure.

[0099] The cross-sectional shape of the socket part 520 matching the shape of the connecting frame 530 can be a trapezoidal shape, a rectangular shape, a circular shape, etc. with a thickness t of a set size.

[0100] The socket part 520 can be made of the same metal material as the upper structure 100 and the lower structure 200 by welding or the like.

[0101] When the cross-sectional shape of the socket part 520 has a trapezoidal shape or a rectangular shape, considering the cold rolling processability including the metal elongation rate, the folded surface of the socket part 520 can have a rounded corner Rf, and the rounded corner Rf has a curvature of a set size to avoid cracks caused by excessive folding.

[0102] In addition, the interior of the socket part 520 of the connecting part 500 may include at least one roller part 550 for supporting the mooring device cable 540 passing through the socket part 520.

[0103] A roller support 551 may be provided on the inner side surface of the socket part 520 for rotatably supporting the roller part 550 arbitrarily.

[0104] In addition, the positive pressure applying device 600 may include an injection pipe 610, a valve cover 620, and a support 630.

[0105] The injection pipe 610 is arranged to communicate with the communication part 103 and can inject gas for applying positive pressure.

[0106] In addition, the valve cover 620 is arranged at the upper end of the injection pipe 610 and can close the injection pipe 610.

[0107] The support 630 is coupled to the setting part 101 and can support the injection pipe 610.

[0108] For example, the positive pressure applying device 600 may be composed of a snap valve or the like. By using the positive pressure applying device 600 to periodically confirm the positive pressure inside the positive pressure applying device 600, it is possible to quantitatively monitor the state of damage and corrosion of the floating body 10 for the photovoltaic power generation system, and airtightness can be ensured by applying additional positive pressure.

[0109] The injection pipe 610 of the positive pressure applying device 600 can inject air or carbon dioxide (CO 2 ) gas or the like at a set pressure (for example, a pressure higher than atmospheric pressure).

[0110] In particular, when carbon dioxide is injected into the injection pipe 610 and pressure is applied to the interior of the upper structure 100, the rate of internal corrosion where the chloride ions and oxygen in the seawater entering due to crevice corrosion or the like occurring on the floating body 10 for the photovoltaic power generation system react can be significantly delayed.

[0111] In addition, a pressure gauge (not shown in the figure) for measuring the internal pressure of the injection pipe 610 may be provided on the injection pipe 610, and a notification part (not shown in the figure) may be provided on the pressure gauge for receiving the pressure information measured by the pressure gauge and notifying the operator when the measured pressure is reduced to below the set pressure.

[0112] In addition, a pedal or passage (not shown in the figure) or the like for the maintenance and safety inspection of the floating body 10 may be provided on the floating body 10 for the photovoltaic power generation system.

[0113] In addition, as Figure 7 shown, the upper structure 100 and the lower structure 200 may include a plurality of recesses 120, 220 for generating turbulence on the surface.

[0114] The concave portions 120 and 220 can be processed by stamping or the like to generate turbulence on the surfaces of the upper structure 100 and the lower structure 200.

[0115] The concave portions 120 and 220 cause turbulence on the surfaces of the upper structure 100 and the lower structure 200, thereby reducing the area where wake is generated due to the tidal current or sea breeze flowing along the floating body 10 for a photovoltaic power generation system, reducing the pressure drag acting on the floating body 10 for a photovoltaic power generation system, and minimizing the attachment of marine organisms.

[0116] In addition, a photovoltaic power generation system according to an embodiment of the present invention may include the floating body as described above.

[0117] Hereinafter, reference will be made to Figures 1 to 7 describe the operation of the floating body for a photovoltaic power generation system according to an embodiment of the present invention.

[0118] First, the floating body 10 for a photovoltaic power generation system has a spherical shape as a whole through the upper structure 100 and the lower structure 200.

[0119] Therefore, on the sea where the sea breeze blows or the tidal current flows from an unknown direction, the resistance to external forces such as sea breeze load and wave load is small, and the incident waves form streamlines (penetrating waves) along the surface of the floating body 10 for a photovoltaic power generation system, so that they can naturally propagate to the inner side of the lower part of the floating type offshore photovoltaic power generation system.

[0120] The resistance (Fd) generated on the floating body 10 for a photovoltaic power generation system can be expressed by the speed (V) of the sea breeze or tidal current acting on the floating body, the projected cross-sectional area (A) in the fluid flow direction, the density (ρ) of the fluid, the drag coefficient (Cd) related to the projected cross-sectional shape of the floating body, etc., as shown in formula (1).

[0121] Fd = ρAV 2 Cd / 2 --- Formula (1)

[0122] If it is assumed that the projected cross-sectional area (A) in the fluid flow direction is the same, the magnitude of the resistance (Fd) depends on the drag coefficient (Cd) related to the projected cross-sectional shape of the floating body. When it is rectangular, Cd is 0.82, when it is a vertical flat plate, Cd is 1.2, when it is a long cylindrical shape, Cd is 0.82, when it is a short cylindrical shape, Cd is 1.15, and when it is a sphere, it is 0.47.

[0123] Therefore, the shapes of the floating bodies used in the comparative examples are plate-shaped, rectangular, conical, or cylindrical, etc., and the drag coefficient changes according to the flow direction of the tidal current, and its value is also greater than that of the sphere given in the embodiment of the present invention.

[0124] In addition, the upper structure 100 has an upward direction ( Figure 1a hemispherical shape protruding in the Y direction), so that seawater (water) caused by external forces can pass through smoothly.

[0125] At the same time, the lower structure 200 has a hemispherical shape protruding downward ( Figure 1 in the Y direction) and has buoyancy, so that seawater caused by external forces can pass through smoothly, enabling the upper structure 100 disposed on the upper part of the lower structure 200 to float on the water surface.

[0126] In addition, the upper structure 100 and the lower structure 200 are made by metal stamping that plastically deforms metal discs, so they can have excellent corrosion resistance and strong resistance to immersion surface corrosion and crevice corrosion of the floating body 10.

[0127] Furthermore, the floating body 10 for a photovoltaic power generation system includes: an upper flange portion 110 that extends outward from the upper structure 100; a lower flange portion 210 that extends outward from the lower structure 200; and a fixing portion 300 for joining the upper flange portion 110 and the lower flange portion 210.

[0128] In addition, the upper flange portion 110 includes a first upper groove 113 protruding upward, the lower flange portion 210 includes a first lower groove 213 recessed downward and configured to correspond to the first upper groove 113, and a first non-metallic airtight gasket 400 is disposed between the first upper groove 113 and the first lower groove 213.

[0129] In addition, the upper flange portion 110 includes a second upper groove 115 outside the first upper groove 113, the lower flange portion 210 includes a second lower groove 215 configured to correspond to the first lower groove 213, and a second non-metallic airtight gasket 410 can be disposed between the second upper groove 115 and the second lower groove 215.

[0130] Furthermore, the upper flange portion 110 includes an upper flat portion 117 between the first upper groove 113 and the second upper groove 115, and the lower flange portion 210 includes a lower flat portion 217 configured to correspond to the upper flat portion 117 between the first lower groove 213 and the second lower groove 215.

[0131] In addition, a third non-metallic airtight gasket 420 is disposed between the upper flat portion 117 and the lower flat portion 217.

[0132] As described above, by including components related to the upper flange portion 110, the lower flange portion 210, and the fixing portion 300, it is possible to prevent seawater from entering the interior of the floating body 10 for a photovoltaic power generation system, resulting in crevice corrosion and loss of buoyancy.

[0133] Furthermore, a connecting portion 500 is provided on the installation portion 101 of the floating body 10 for a photovoltaic power generation system, so that one floating body 10 can be connected to another adjacent floating body 10.

[0134] That is to say, by arranging a plurality of socket parts 520 at set intervals based on the center of the connecting part 500, a connecting frame 530 can be inserted for connecting another floating body 10 adjacent to one floating body 10.

[0135] The cross-sectional shape of the socket part 520 matching the shape of the connecting frame 530 can be a trapezoidal shape, a rectangular shape, a circular shape, etc., and has a thickness t of a set size.

[0136] In addition, at least one roller part 550 is provided inside the socket part 520 of the connecting part 500, so that the mooring device cable 540 passing through the socket part 520 can be supported.

[0137] Furthermore, the central part of the setting part 101 includes a communication part 103 communicating with the internal hollow part of the upper structure 100, and a positive pressure applying device 600 is arranged in the communication part 103 for applying positive pressure to the inside of the upper structure 100.

[0138] By regularly checking the positive pressure in the positive pressure applying device 600 by using such a positive pressure applying device 600, the state of whether the floating body 10 for the photovoltaic power generation system is damaged and corroded can be quantitatively monitored, and the airtightness can be ensured by applying additional positive pressure.

[0139] In particular, when carbon dioxide is injected into the injection pipe 610 and the pressure inside the upper structure 100 is applied to a set pressure, the speed of internal corrosion in which chloride ions and oxygen in the seawater entering due to crevice corrosion and the like occur on the floating body 10 for the photovoltaic power generation system can be significantly delayed.

[0140] The positive pressure applying device 600 applies a gas with a pressure higher than the atmospheric pressure to the inside of the upper structure 100. According to the change of the sea surface level and the seasonal temperature change in different set sea areas, the variable setting of the buoyancy of the floating body 10 can be simply realized, and seawater causing crevice corrosion can be fundamentally prevented from infiltrating into the inside of the floating body 10.

[0141] In addition, the upper structure 100 and the lower structure 200 have concave parts 120 and 220 on the surface, so that turbulence can be generated on the surfaces of the upper structure 100 and the lower structure 200.

[0142] As described above, turbulence is generated on the surfaces of the upper structure 100 and the lower structure 200 through the concave parts 120 and 220, so that the area where wake is generated due to the tidal current or sea breeze flowing along the floating body 10 for the photovoltaic power generation system can be reduced, the pressure resistance acting on the floating body 10 for the photovoltaic power generation system can be reduced, and the adhesion of marine organisms can be minimized as much as possible.

[0143] In the following, reference will be made to Figure 8A description will be given below. The floating body settlement rate used hereinafter refers to the ratio of the total volume of the floating body to the volume of the floating body submerged below the sea surface.

[0144] Figure 8 It is a comparison chart of the number of floating bodies with respect to the settlement volume (settlement rate) of the comparative example and the examples of the present invention.

[0145] Figure 8 It is a comparison chart. When the weight of the photovoltaic panel in a 0.1 MW floating offshore photovoltaic power generation system is 5.56 tons (371 pieces) and the weight of the structure is 15 tons, according to the floating body settlement rate, the number of positive pressure applied spherical floating bodies made of high density polyethylene (HDPE: High Density Polyethlene) in the comparative example and the number of positive pressure applied spherical floating bodies made of highly corrosion-resistant metal material (duplex STS) of the present invention were compared.

[0146] In addition, as the external environment, it is assumed that the seawater temperature is 40 degrees, and carbon dioxide (CO 2 ) with a pressure of 1.1 atmospheres (atm) higher than the atmospheric pressure is applied to the inside of the floating body. As the size of the spherical floating body, it is assumed that the radius Ra of the sphere is 400 mm, and the radius width of the flange outside the sphere (R7 - Ra) is 150 mm (refer to Figure 2 ).

[0147] At this time, the number of floating bodies is determined by dividing the sum of the self-weight of the photovoltaic panel and the self-weight of the structure by the net buoyancy force that a single floating body needs to support (buoyancy force - self-weight of the floating body - self-weight of CO 2 inside the floating body).

[0148] In addition, when the yield strength of the highly corrosion-resistant metal material (duplex STS) used in the present invention is 450 MPa and the yield strength of the high density polyethylene in the comparative example is 17.8 MPa, the durability of the floating body is estimated by the design safety factor, which is the ratio of the stress generated on the surface of the floating body due to the gas pressure inside the floating body to the yield strength of the floating body material.

[0149] As Figure 8 shown, as the floating body settlement rate increases, the net buoyancy force increases, and it can be seen that the total number of floating bodies in the floating photovoltaic power generation system decreases.

[0150] In addition, assuming that the thickness t of the floating body material is 0.8 mm, when the settlement rate is small, for the comparative example where the inside of the floating body is filled with foam and the external material uses HDPE material, since the density of HDPE is relatively lower than that of metal, the number of floating bodies is less than that of the present invention.

[0151] However, at this time, the design safety factor of the metal floating body according to the embodiment of the present invention is 16 or more, while the design safety factor of the comparative example with the thickness t of the floating body material being 0.8 mm is 0.64. It can be seen that the comparative example cannot ensure durability and damage occurs.

[0152] In addition, when the thickness of the HDPE material floating body in the comparative example is increased to 19 mm to ensure that the design safety factor of the comparative example is the same as that of the embodiment of the present invention, it can be seen that the number of floating bodies required is more than that of the embodiment of the present invention.

[0153] In addition, according to the number of floating bodies in the embodiment of the present invention, when determining the thickness of the HDPE material in the comparative example under the condition of a similar number of floating bodies, the thickness is 6.15 mm, and the design safety factor at this time is 5. Therefore, for the difference in the floating bodies used in the comparative example and the embodiment of the present invention, even excluding the environmental impact, it can be seen that there is a difference of more than 3 times in terms of durability.

[0154] In order to ensure a service life of 20 years in a marine environment with two tidal phenomena occurring every day, the durable life of the floating body needs to exhibit an almost infinite fatigue life.

[0155] For this purpose, assuming that the maximum external force in the marine environment is a typhoon [the pressure of a severe typhoon is about 951 hPa, the speed of the typhoon is about 70 m / s, and the speed of the ocean tide is about 7.4 km / h], the floating body not only bears the static load related to its own weight in the vertical direction but also bears the dynamic load (the pressure and speed of the ocean tide or sea breeze) in the direction parallel to the sea surface.

[0156] Generally, in a cycle life of 10^6 cycles (>20 years) with an infinite life, if the thickness of the floating body material according to the present invention is 0.8 mm, the allowable strength of the metal floating body is 219 MPa. This is the result of considering the tensile strength of the material of 620 MPa, the metal surface processing method considered when making the sphere, the load conditions (tension, compression, torsion), the use temperature conditions, and other use environments. Regardless of the floating body settlement rate, the safety factor for the dynamic load is more than 9.

[0157] At this time, the dynamic load safety factor is the value obtained by dividing the sum of the resistance of the underwater immersion part caused by the ocean tide and the resistance of the non-immersion part caused by the typhoon by the allowable force calculated from the allowable strength, floating body thickness, floating body radius, etc.

[0158] Figure 8 In the case of the spherical floating body with an HDPE thickness of 6.15 mm shown in the comparative example, the safety factor for the dynamic load is 2.83. Therefore, for the difference in the floating bodies used in the comparative example and the embodiment of the present invention, even excluding the environmental impact, it can be seen that there is a difference of more than 3 times in terms of the safety of long-term service life.

[0159] If a rectangular floating body is used in the comparative example instead of the spherical floating body according to the embodiment of the present invention, the safety factor of the dynamic load of the comparative example may be smaller due to the difference in the resistance index (i.e., the drag coefficient) of the fluid energy.

[0160] Although the present disclosure has been described by the preferred embodiments as above, the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains can make various modifications and variations without departing from the scope of the claims.

[0161] Symbol Explanation

[0162] 10: Floating body for photovoltaic power generation system

[0163] 100: Upper structure

[0164] 101: Installation part

[0165] 200: Lower structure

[0166] 300: Fixing part

Claims

1. A floating body for a photovoltaic power generation system, which comprises: an upper structure having a flat-shaped setting portion on one of its surfaces; a lower structure configured to correspond to the upper structure and including a hemispherical shape protruding in a direction away from the setting portion; and a fixing portion for coupling the upper structure and the lower structure.

2. The floating body for a photovoltaic power generation system according to claim 1, wherein the upper structure has any one of a hemispherical shape, a semi-conical shape, and a semi-elliptical shape.

3. The floating body for a photovoltaic power generation system according to claim 1 or 2, which further comprises: an upper flange portion extending in an outer direction of the upper structure; and a lower flange portion configured to correspond to the upper flange portion and extending in an outer direction of the lower structure.

4. The floating body for a photovoltaic power generation system according to any one of claims 1 to 3, wherein the fixing portion uses screws or welding to couple the upper structure and the lower structure or uses bolts or welding to couple the upper flange portion and the lower flange portion.

5. The floating body for a photovoltaic power generation system according to any one of claims 1 to 4, wherein the upper flange portion includes a first upper groove, and the lower flange portion includes a first lower groove configured to correspond to the first upper groove.

6. The floating body for a photovoltaic power generation system according to any one of claims 1 to 5, wherein a first non-metallic airtight gasket is disposed between the first upper groove and the first lower groove.

7. The floating body for a photovoltaic power generation system according to any one of claims 1 to 6, wherein the upper flange portion includes at least one second upper groove outside the first upper groove, and the lower flange portion includes a second lower groove configured to correspond to the second upper groove.

8. The floating body for a photovoltaic power generation system according to any one of claims 1 to 7, wherein a second non-metallic airtight gasket is disposed between the second upper groove and the second lower groove.

9. The floating body for a photovoltaic power generation system according to any one of claims 1 to 8, wherein the upper flange portion includes an upper flat portion between the first upper groove and the second upper groove, and the lower flange portion includes a lower flat portion configured to correspond to the upper flat portion between the first lower groove and the second lower groove.

10. The floating body for a photovoltaic power generation system according to any one of claims 1 to 9, wherein a third non-metallic airtight gasket is disposed between the upper flat portion and the lower flat portion.

11. The floating body for a photovoltaic power generation system according to any one of claims 1 to 10, wherein the materials of the first non-metallic airtight gasket, the second non-metallic airtight gasket, and the third non-metallic airtight gasket are silica gel.

12. The floating body for a photovoltaic power generation system according to any one of claims 1 to 11, wherein a connecting portion can be provided on the setting portion for connecting one floating body and another adjacent floating body.

13. The floating body for a photovoltaic power generation system according to any one of claims 1 to 12, wherein the setting portion includes a communication portion communicating with the internal hollow portion of the upper structure, A positive pressure applying device for applying positive pressure to the inside of the upper structure is provided in the connecting part.

14. The floating body for a photovoltaic power generation system according to any one of claims 1 to 13, wherein, the connecting part includes: a first setting hole for setting the positive pressure applying device; and a socket part for setting a connecting frame for connecting with adjacent floating bodies for a photovoltaic power generation system.

15. The floating body for a photovoltaic power generation system according to any one of claims 1 to 14, wherein, a plurality of the socket parts are arranged at set intervals based on the connecting part.

16. The floating body for a photovoltaic power generation system according to any one of claims 1 to 15, wherein, the cross-sectional shape of the socket part has a trapezoidal shape.

17. The floating body for a photovoltaic power generation system according to any one of claims 1 to 16, wherein, at least one roller part for supporting a mooring device cable passing through the socket part is provided inside the socket part.

18. The floating body for a photovoltaic power generation system according to any one of claims 1 to 17, wherein, the positive pressure applying device includes: an injection pipe communicated with the connecting part for injecting gas for applying positive pressure; a valve cover provided on the injection pipe for closing the injection pipe; and a support body coupled to the setting part for supporting the injection pipe.

19. The floating body for a photovoltaic power generation system according to any one of claims 1 to 18, wherein, Air or carbon dioxide (CO 2 ) gas is injected into the injection tube at a pressure of a set size.

20. The floating body for a photovoltaic power generation system according to any one of claims 1 to 19, wherein, the upper structure and the lower structure are made of a metal material.

21. The floating body for a photovoltaic power generation system according to any one of claims 1 to 20, wherein, the metal material is any one material selected from austenitic stainless steel, ferritic stainless steel, and duplex stainless steel.

22. The floating body for a photovoltaic power generation system according to any one of claims 1 to 21, wherein, the upper structure and the lower structure include recesses on the surface.

23. The floating body for a photovoltaic power generation system according to any one of claims 1 to 22, wherein, the height of the upper structure and the lower structure is set to be less than the radius of the upper structure and the lower structure.

24. The floating body for a photovoltaic power generation system according to any one of claims 1 to 23, wherein, the socket part is made of the same metal material as the upper structure and the lower structure.

25. A photovoltaic power generation system, which includes the floating body according to any one of claims 1 to 24.

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