FLOATING SUPPORT STRUCTURE FOR PV MODULES

Description

[0001] The invention relates to a device for generating electrical energy using photovoltaics in an aquatic environment. In particular, it is an adaptable and modular device consisting of several inflatable, buoyant pontoons on which a structure for accommodating photovoltaic (PV) modules rests.

[0002] Floating PV systems have been developed over the past decade. They meet both the need for an environmentally friendly method of generating electricity and the desire to minimize the space required for PV systems. The advantages of these structures are numerous: In addition to keeping agricultural production areas free, they enable the economic use of bodies of water (irrigation basins, lakes, etc.) and brownfield sites (disused quarries). The water covered by floating photovoltaic systems also benefits, as the PV systems limit the warming and evaporation of the water. They also prevent the proliferation of algae and invasive plants by limiting the temperature and reducing solar radiation on the covered areas.

[0003] Floating PV systems are known from FR 3 084 052, DE 102011009424 A1, and WO 2007062278 A. The floating bodies of the PV system previously known from FR 3 084 052 are inflatable. Summary of the invention

[0004] The present invention aims to at least partially overcome the disadvantages of the prior art and in particular to provide a modular, adaptable, easily transportable and economical floating PV system.

[0005] This object is achieved according to the invention in a floating support structure for photovoltaic modules, according to claim 1, comprising at least two floating bodies and supports arranged next to one another or parallel to one another, on which PV modules are mounted, in that the supports have two straight sections whose longitudinal axes enclose an angle β, wherein the angle β is less than 180° and greater than 135°, that a membrane is provided between two or more supports arranged next to one another, and that at least two supports of the support structure and the membrane and / or two floating bodies and the membrane form a membrane-stiffened supporting structure. The connection between the supports and the membrane or between the floating bodies and the membrane can be made directly or indirectly via an intermediate piece, e.g. a gusset plate or a rail.

[0006] The hybrid construction according to the invention, comprising supports and a membrane, creates a very lightweight yet resilient supporting structure that can easily be arranged on floating bodies. One advantage of the structure according to the invention is that the supports absorb the vertical loads, in particular the weight, but also wind loads, which are introduced into the supporting structure by the PV modules, and transfer them to the floating bodies. Transverse forces or shear forces, which act on the structure essentially parallel to the water surface on which the floating bodies float, are predominantly absorbed by the membrane. The membrane can absorb or dissipate these forces across its entire surface, resulting in a very resilient yet very lightweight construction.

[0007] A further advantage of the membrane-stiffened supporting structure according to the invention is that with increasing weight forces acting on the supports of the supporting structure, the supports tend to expand. This process is also absorbed by the membrane arranged between the end points of the supports. This prestresses the membrane according to the invention, which further increases the stiffness and load-bearing capacity of the supporting structure according to the invention.

[0008] To ensure the transmission of force between the supports and the diaphragm in a simple manner, even over a long period of operation, the ends of the supports and the diaphragm are connected directly or indirectly in a form-fitting or friction-locking manner. In a simple embodiment, a form-fitting connection can consist of holes in the diaphragms at the appropriate locations, which are usually reinforced by metal (hole-reinforcing) rings. A screw can be inserted through these holes, with the aid of which the support and the diaphragm are connected in a form-fitting manner. This type of form-fitting connection is very easy to manufacture.This results in a detachable connection, so that firstly the assembly of the supporting structure according to the invention is simplified and even in the event of damage, be it to the support or the membrane, the damaged component can be replaced on site and without major effort.

[0009] In an advantageous embodiment, the supports consist of an extruded profile, made, for example, of aluminum. The extruded profile makes it possible to provide a load-adapted cross-section that ideally accommodates the occurring loads while requiring minimal material usage. Furthermore, functional surfaces can be incorporated into the extruded profile. For example, a "T" groove can be formed in the extruded profile so that the PV modules can be easily screwed to the support using T-nuts or suitably shaped hammer-head screws.

[0010] The supports have two straight sections whose lengths approximately correspond to the length of the PV modules, allowing the PV modules to rest directly on the straight sections of the supports and be secured there. It is usually sufficient for the straight sections to be approximately two-thirds the length of the PV modules. This enables an even more compact and cost-effective design.

[0011] If the supports are made from an extruded profile, it is possible to design this extruded profile without additional manufacturing effort so that the PV modules can be mounted on the supports without a separate frame. This saves material and costs and reduces the system weight.

[0012] The angle between the straight sections of the supports according to the invention is usually created by bending an extruded profile. It is easily possible to bend aluminum extruded profiles to an angle between 0° and 45°. This is especially true when a large bending radius is possible. This is precisely the case with the application according to the invention.

[0013] In a preferred embodiment, inflatable floats or floats with a flexible membrane made from a fabric-reinforced tarpaulin are considered as floats. This is preferably a glass fiber-reinforced PVC tarpaulin, as has been known for years in the field of truck covers (so-called truck tarpaulins). An airtight float is made from this tarpaulin, which is then inflated on site. Optionally, the float can be filled with a buoyant filling material such as cork, Styrofoam, air-filled plastic balls or even smaller floats such as PET beverage bottles or other sealable hollow bodies. These bottles can be placed inside the float, where they serve as floats, instead of being recycled.In some cases, for example when a cuboid hollow body is used as a filler, the hollow body can give the floating bodies additional mechanical strength.

[0014] One advantage of fabric-reinforced PVC tarpaulins is that they can be joined together to form an airtight, flat seal, for example, using ultrasonic welding. This makes it very simple and reliable to produce an airtight floating body from such tarpaulins. At one or both ends of the floating body, it can be sealed watertight and airtight using a roll-top closure familiar from the outdoor sector. These roll-top closures, common on bicycle panniers and backpacks, are waterproof. They can also be made airtight if the film is rolled up several times and / or an adhesive or sealant is applied to the tarpaulin in the area of ​​the roll-top closures before rolling.

[0015] It is also possible to attach tabs or pockets made of the same material to the outside of the float, also by ultrasonic welding, so that the actual supporting structure can be connected to the float using these tabs or pockets.

[0016] For example, a supporting structure or a coupling element of the supporting structure can be connected to such a strap, similar to a tensioning strap. However, it is also possible to provide one or more holes in the straps and use the holes to screw the coupling element to the strap, and thus also to the floating body.

[0017] It is also possible to provide a narrow, elongated pocket on the outside of the float, open at least at one end and possibly with several openings. A rod or tube can be inserted into each of the elongated pockets. This rod or tube has a fastening thread in the area of ​​the openings in the pocket. Using these fastening threads, the coupling elements or supports can be screwed directly to the rod or tube. This stiffens the float through the rod / tube. Furthermore, the forces of the supporting structure are transferred into the float along its entire length.

[0018] Of course, it is advantageous if these holes are reinforced with metal hole reinforcement rings so that the tabs or pockets do not tear where the fastening screw is attached.

[0019] It is possible and advantageous for the coupling elements connecting the support structure to the floats to create a positive, material, or force-fit connection between the floats and the support structure. For example, it is possible to attach the coupling element to the float using a clamp, similar to a screw clamp, with appropriately shaped and positioned tabs. However, it is also possible, as already mentioned above, to attach the coupling element to a tab using screws or cotter pins with appropriate holes.

[0020] It is also possible for the coupling element to have flat feet that are inserted into pockets open on one side on the outside of the float. If several such pockets are present, the coupling element is held in place by a positive fit as soon as the float is inflated or filled with filler.

[0021] To improve the efficiency and cost-effectiveness of the floating PV system, the membrane reflects the light incident on it onto the PV modules, so that the underside of the PV modules is also exposed to sunlight. In a further advantageous embodiment of the invention, the PV modules are so-called bifacial PV modules, which can convert sunlight incident on both their top and bottom sides into electrical energy.

[0022] It has been found that the angle β should preferably be less than 170° and greater than 150°, and that it is particularly advantageous if the angle β is less than 165° and greater than 155°. This results in particularly favorable operating behavior of the PV modules due to the inclined position of the PV modules, while also making the support structure according to the invention, with its supports and membrane, particularly resilient. Overall, this results in a very lightweight yet rigid support structure that accommodates the PV modules.

[0023] Further advantages and advantageous embodiments of the invention can be found in the following drawings, their description, and the patent claims. All features disclosed in the drawings, their description, and the patent claims may be essential to the invention both individually and in any combination.

[0024] They show: Figure 1 is an isometric view of an embodiment of a floating PV system according to the invention, Figure 2 is a side view of the floating PV system, Figure 3 is a section of the Figure 2 in an enlarged view, Figure 4 a longitudinal section through an embodiment of an oscillating body with attached pocket and Figure 5 sectional views through a floating body according to Figure 4 . Description of the embodiment

[0025] In the Figure 1 An isometric view of an embodiment of a floating PV system according to the invention is shown. It comprises several rows of floating bodies 1 arranged parallel to each other. As can be seen from the Figures 1 and 2 several pairs of floating bodies 1 can be arranged next to each other, so that several rows of PV modules 3 are arranged next to each other. In the embodiment according to the Figure 1 and 2Three times two floating bodies 1 are arranged next to each other, so that a total of six rows of PV modules are arranged next to each other.

[0026] Two floating bodies 1 each carry two rows of PV modules 3, which are arranged in the manner of a gable roof.

[0027] The PV modules 3 are, as shown in the Figures 2 and 3 better visible, carried by supports 5, which in turn are connected to the floating bodies 1. The water level is in the Figure 2 marked with the reference number 9.

[0028] The outer floats 1 of the Figures 1 and 2 do not carry any PV modules 3. 5. Rather, 2 guy ropes 7 are arranged on these outer floating bodies, with the help of which the floating PV system is protected from drifting away and held in a predetermined position.

[0029] In addition to the supports 5, to which the PV modules 3 are mounted, an essential component of the support structure according to the invention is a membrane 11, which is stretched between two parallel floating bodies 3. The membrane 11, together with the supports 5 and possibly other elements, forms a membrane-stiffened supporting structure.

[0030] The Figure 3 shows a section of the PV system according to the Figures 1 and 2 slightly enlarged. This figure shows the shape of the supports 5 better. As can be seen from the Figure 3 The supports 5 have two straight sections 13 that enclose an angle β of, for example, 165°. The angle β results in the gable-roof-shaped arrangement of the two rows of PV modules 3.

[0031] In this embodiment, a connecting section between the straight sections 13 of the beam 5 is formed as a horizontal section. This divides the bending angle between the straight sections 13 into two equal angles. This can offer advantages when bending the beam 5 from a straight extruded profile. It is also possible to provide a large radius of curvature between the straight sections 13 to prevent the beam 5 from buckling during bending.

[0032] At the outer ends, the support 5 is also slightly angled. The angled, short end sections are designated 15. Bending the end sections 15 creates a certain vertical distance between the PV modules 3 and the floating bodies 1. Furthermore, the end sections 15 can be angled so that they rest tangentially on the floating bodies, which are cylindrical in this embodiment.

[0033] The membrane 11 is connected to the supports 5 in the area of ​​the end sections 15, so that the supports 5 and the membrane 11 form a membrane-stiffened supporting structure.

[0034] The supports 5 are advantageously manufactured as extruded profiles, for example, from aluminum. This allows functional surfaces to be formed on the extruded profile, which, for example, provide a support surface for the PV modules 3 in the area of ​​the straight sections 13. T-slots can also be formed into the extruded profile, so that the PV modules 3 can be easily screwed to the support in the area of ​​the straight sections 13 using T-nuts or hammer-head screws.

[0035] Furthermore, it is possible to dimension the supports 5 according to the expected loads, so that a resilient structure is created with little material expenditure.

[0036] When designing the extruded profile, it is important to ensure that the beam 5 can still be bent to create the angle β between the straight sections 13. However, the end sections 15 also form an angle with the straight sections 13, so the beams 5 must also be bent in the transition between the sections 13 and the end sections 15.

[0037] Based on the Figure 3 It becomes clear that vertical loads absorbed by the beam 5 cause the beam 5 to tend to deflect laterally. Then, the distance between the end sections 15 of a beam 5 would increase with increasing load. However, this is undesirable.

[0038] Because the end sections 15 are connected to the membrane 11 in a form-fitting or force-fitting manner, the membrane 11 stiffens the supports 5, effectively preventing lateral deflection of the end sections 15. This allows the supports 5 to be made smaller and lighter, which reduces manufacturing costs and the weight of the floating PV system.

[0039] The membrane 11 is preferably made of a material that reflects the incident sunlight, so that the underside of the PV modules 3 is also exposed to sunlight. As a result, the PV modules 3 are preferably bifacial PV modules that reflect sunlight both on the top side (top in the Figure 3) and from the bottom. To optimize the efficiency and cost-effectiveness of a PV system, it may be advisable to maintain a certain distance between the PV modules, both longitudinally and transversely. This reduces the number of PV modules for the same footprint; due to the reflective membrane and the use of bifacial PV modules, the electrical energy yield remains virtually the same.

[0040] To protect the floating bodies 1 from UV radiation from sunlight, it is possible to extend the membrane 11 beyond the end sections 15 of the supports 5, so that the part of the floating body that would be exposed to sunlight is protected from it. This almost completely prevents the aging process of the floating bodies 1 caused by UV radiation. Furthermore, the reflection of sunlight onto the underside of the adjacent PV modules is increased.

[0041] In the Figure 3 On one side, namely at the right end of the membrane 11, it is designed in such a way that it protects part of the floating body 1 from sunlight.

[0042] In addition to its structural advantages and the increase in power generation by reflecting incoming sunlight, membrane 11 has another important advantage. Together with the PV modules 3, membrane 11 reduces sunlight penetration into the water. This reduces water heating and, as a result, less algae growth. In many cases, the quality of the water and the habitat created by the water are beneficial for fish and aquatic plants.

[0043] Based on the Figures 4 and 5 the structure of the floating body 1 and the coupling of the membrane-reinforced supporting structure comprising the support 5 and the membrane 11 with the floating body 1 will be illustrated.

[0044] The floating body 1 is preferably an inflatable floating body, made, for example, from so-called truck tarpaulin (a fabric-reinforced PVC film). These truck tarpaulins can be welded together to form an airtight seal, for example, using ultrasonic welding. The weld seams are one to two centimeters wide and can be of almost any length.

[0045] Because the weld seams are so wide, a very tight and resilient welded joint is created. In other words, a rectangular piece of truck tarpaulin can be welded into a cylinder with a weld seam running parallel to the cylinder's longitudinal axis. This weld seam is extremely resilient and airtight and gas-tight. Accordingly, a base can be welded to the ends of the floating body 1, which is also airtight and gas-tight.

[0046] Similarly, it is also possible to hermetically seal openings, for example, in the form of screw caps, onto the truck tarpaulin using ultrasonic welding. This makes it possible to insert fillers such as cork, Styrofoam, or even PET bottles into the interior of the floating body 1. These fillers ensure that even in the event of a hole in the truck tarpaulin, the floating body 1 does not lose its buoyancy but remains buoyant. The truck tarpaulin then serves to hold the fillers together.

[0047] There are many ways to connect the floats 1 to the supporting structure (especially the supports 5) in a form-fitting or force-fitting manner. For example, it is possible to attach tabs to the outside of the float by ultrasonic welding and to attach the supporting structure to these tabs by clamping or form-fitting. Another option is hook and loop fasteners. Figure 4 An embodiment is shown in which an elongated pocket 17 is welded to the exterior of the floating body 1. This elongated pocket 17 is open at both ends. A spar 19, which can be made, for example, as a square aluminum tube, is inserted into this pocket. In this embodiment, the pocket 17 has two openings 21, the spacing of which corresponds to the spacing of the supports 5 of the membrane-stiffened supporting structure.

[0048] Where the openings 21 are formed in the pocket 17, the spars 19 have internal threads so that the support 5 can be screwed to the spar 19 using a fastening screw 23. This firstly ensures that the supporting structure or the supports 5 are connected to the floating body 1. Furthermore, the point loads that must be introduced from the support 5 into the floating body 1 are distributed over a large length of the floating body 1 via the spar 19. This helps to avoid point overloads or deformations of the floating body 1. Furthermore, the spar 19 ensures that the distance between two adjacent supports 5 is kept constant and that tensile forces in the membrane 11 do not change this distance. This is important in order to keep the mechanical loads on the PV modules 3 low.

[0049] In the Figure 5 is a section along the line AA according to Figure 4This illustration shows that the support 5 can be connected to the beam 19 by a screw 23. The screw 23 extends through the opening 21 into the pocket 17 and is screwed into an internal thread of the beam 19.

[0050] As a positive side effect, this construction results in a clamping effect between the support 5 and the spar 19. The elongated pocket 17 is clamped between these two components, so that there is a force-locking and a form-locking connection and force transmission between the supports 5 and the floating body 1.

[0051] As already mentioned, the elongated pocket 17 is connected to the outside of the floating body 1 by a weld seam 25. The weld seam 25 is, for example, one to two centimeters wide, resulting in a flat and therefore very resilient, material-to-material connection between the floating body 1 and the elongated pocket 17.

[0052] In the Figure 5 A section along line BB is also shown. It shows the "undisturbed" structure consisting of float 1, pocket 17, and spar 19, representing the areas where no opening 21 is formed in pocket 17. List of reference symbols:

[0053] 1 Floating body 3 PV module 5 Support 7 Guy wires 9 Water level 11 Membrane 13 Straight section of the support 5 15 End section of the support 5 17 Elongated pocket 19 Beam 21 Opening 23 Screw 25 Weld seam

Claims

1. Floating support structure for photovoltaic modules, comprising at least two floating bodies (1) and supports (5) arranged next to one another, in particular parallel to one another, on which PV modules (3) are mounted, characterized in that the supports (5) have two portions (13) of which the longitudinal axes enclose an angle (β), the angle (β) being less than 180° and greater than 135°, and in that a membrane (11) is provided between two or more than two supports (5) or floating bodies (1) arranged next to one another, and in that at least two supports (5) or floating bodies (1) and the membrane (11) form a membrane-reinforced supporting structure.

2. Floating support structure according to claim 1, characterized in that the end portions (15) of the supports (5) and the membrane (11) are directly or indirectly connected to one another in a form-fitting or force-fitting manner.

3. Floating support structure according to claim 1 or 2, characterized in that the supports (5) consist of an extruded profile, and in that the angle (β) is created by bending the extruded profile.

4. Floating support structure according to any of the preceding claims, characterized in that the floating bodies (1) are made of a fabric-reinforced tarpaulin, preferably a glass-fiber-reinforced PVC tarpaulin and in that floating bodies (1) are inflatable and / or at least partially filled with a buoyant filling material.

5. Floating support structure according to claim 4, characterized in that the floating bodies (1) have one or more closable openings for inflation and / or filling.

6. Floating support structure according to claim 4 or 5, characterized in that tabs or pockets (17) made of fabric-reinforced tarpaulin are welded to the outside of the floating bodies (1).

7. Floating support structure according to any of the preceding claims, characterized in that they have coupling elements (19, 23) which connect the supports (5) to the floating bodies (1) in a form-fitting, force-fitting and / or integrally bonded manner.

8. Floating support structure according to claim 7, characterized in that the coupling elements enclose the floating body (1).

9. Floating support structure according to claim 6 or 7, characterized in that the coupling elements (19) are inserted or pushed into the pockets (17) of the floating bodies (1).

10. Floating support structure according to any of the preceding claims, characterized in that the membrane (11) reflects the sunlight incident thereon onto the bottom of the PV modules (3).

11. Floating support structure according to any of the preceding claims, characterized in that the PV modules (3) are bifacial PV modules that convert the light incident on both the top and bottom into electrical energy.

12. Floating support structure according to any of the preceding claims, characterized in that the angle (β) is less than 170° and greater than 150°, and in particular in that the angle (β) is less than 165° and greater than 155°.