PHOTOVOLTAIC SYSTEM AND ASSOCIATED USE

Description

[0001] The invention relates to a photovoltaic (PV) system with several bifacial photovoltaic modules arranged upright on a supporting structure.

[0002] The invention also deals with the use of such PV systems for power generation in a specific configuration.

[0003] Conventional PV systems that use unifacial PV modules to generate electricity are often installed at an angle. The only active surface of the PV modules, which can convert solar radiation energy into electrical energy, is typically oriented south. Such systems have the disadvantage of delivering their peak power during midday. This can place a strain on the power grid, particularly in the event of an oversupply of such electricity.

[0004] For this reason, PV systems with PV modules that have active surfaces on both sides have been tested for several years. These PV modules, known as bifacial, are positioned upright so that the front and back are each illuminated by the sun. If the bifacial PV modules of such PV systems are positioned in a north-south direction, they can capture sunlight from east and west, particularly in the early morning and late evening hours. This achieves a power output that is complementary to that of conventional systems, with low levels around midday but peaking in the morning and evening. Such a daily electricity curve characteristic is advantageous in terms of a uniform electricity supply in the grid throughout the day. However, PV systems with bifacial PV modules can also be advantageously used in orientations other than north-south.

[0005] In contrast to unifacial PV modules, bifacial PV modules pose new technical challenges, as the rear side of the modules is also intended to generate electricity. The support structures and installation concepts previously developed for unifacial PV modules are therefore only partially applicable or would require complex and therefore expensive adaptations.

[0006] Supporting structures intended for vertically aligned or upright, in particular bifacial, PV modules are known, for example, from DE 2014 105516 U1, JP 2004 335903, JP 2002 0766416, JP 2003 229591, JP 2006 080568 and US 2001 / 0005583 A1.

[0007] Based on this, it is an object of the present invention to provide a PV system in which several bifacial PV modules can be mounted in a vertical arrangement and which meets the specific requirements of bifacial modules. To this end, a supporting structure is to be provided that is not only cost-effective to manufacture but also enables rapid and therefore cost-effective installation of the PV system. Furthermore, the supporting structure should have sufficient stability under typical weather conditions.

[0008] The invention is also based on the object of improving the efficiency of the conversion of sunlight into electrical energy for PV systems.

[0009] To achieve these objects, the features of claim 1 are provided according to the invention in a photovoltaic system. In particular, to achieve the object in a photovoltaic system of the type mentioned at the outset, it is proposed according to the invention that the supporting structure has a plurality of posts which are fastened, in particular anchored, to or in the ground, wherein bars are fastened to the posts, which in each case connect two adjacent posts to one another, and wherein in each case two posts and two bars define a substantially rectangular mounting field in which at least one PV module is arranged.To achieve the object, it is further provided that the posts are designed in the form of longitudinal profiles, that the posts are further divided into at least one fastening section connected to the ground and a holding section connected thereto, which extends above the fastening section, and that holding surfaces are formed on the posts, to which an associated bar can be attached flatly. The bars are narrower than the posts and are arranged centrally in relation to the posts. In addition, the holding surfaces are designed as flanges on one of the longitudinal profiles and thus as part of the longitudinal profile, or as tabs on respective openings in the longitudinal profiles and thus likewise as part of the longitudinal profile. The respective shape of a tab is predetermined by the shape of the associated opening in the respective longitudinal profile, while the respective flange runs along the entire holding section of the post.It is further provided that the flanges and the tabs extend in the direction of and laterally offset from a plane formed by the PV modules. Finally, it is provided that the respective outer edges of the respective post, which run in the longitudinal direction of the post, are spaced further from said plane of the PV modules than the respective flange or the respective tab.

[0010] A mounting field according to the invention can therefore accommodate one or more PV modules, whereby further subdivisions of the mounting field can also be provided, for example by means of additional bars and / or vertically extending intermediate posts. The mounting field according to the invention can be regarded as substantially rectangular in particular if the mounting field is suitable for receiving a PV module with a rectangular outer contour. Therefore, according to the invention, it can be provided in particular that two posts and two bars each define a mounting field in which at least one PV module is arranged, whereby edges of the posts and bars which are aligned with the PV modules and thus delimit the mounting field are preferably arranged at a uniform distance from the outer edges of the at least one PV module.

[0011] In most installation situations, it is advantageous if the multiple bifacial photovoltaic modules are arranged vertically on the supporting structure.

[0012] In other words, the invention thus provides a supporting structure in which posts and transoms are connected to each other at preferably regular intervals and preferably at right angles, so that two posts and two transoms each define a rectangular mounting field into which a bifacial PV module is inserted in a vertical suspension. This allows the PV modules to collect sunlight from both sides to convert it into electrical energy.

[0013] According to the invention, it is advantageous for the supporting structure to be highly rigid if at least individual transoms are attached to the posts on both sides by means of fastening means. In this case, a suitable fastening of the transoms within the meaning of the invention can be achieved, in particular, by screw connections, in particular drilling screws or threaded screws, by rivets, pins, as well as by welding, gluing, or by simple form-fitting.

[0014] The advantage here is that a PV system according to the invention with the features of claim 1 can be manufactured cost-effectively and installed efficiently and therefore cost-effectively. At the same time, the supporting structure according to the invention ensures high stability, particularly against wind loads, as well as efficient utilization of the active surfaces of the bifacial modules.

[0015] According to the invention, the supporting structure can be anchored in the ground, for example, by means of an anchor. This can be achieved, for example, by ground anchors, ground screws, driven posts, or concrete foundations, with additional guy wires being provided. If anchoring in the ground can be avoided, for example when erecting the PV system on landfill sites, the supporting structure can also be anchored to the ground by weighting the posts to the ground. Furthermore, both the posts and the transoms can be designed in the form of longitudinal profiles, for example as extruded aluminum profiles, which enables particularly economical use of materials and thus a lightweight supporting structure. According to the invention, the supporting structure can be made, for example, from C-, S-, U-, Σ-, or Ω-profiles, in particular from combinations of such profiles.For example, slanted and / or rounded shaped elements can also be provided on the posts and / or transoms to minimize shading of the PV modules. Another embodiment according to the invention provides posts and / or transoms made of hot- or cold-rolled steel, preferably provided with corrosion protection.

[0016] According to the invention, the object can also be achieved by further advantageous embodiments of the subclaims.

[0017] For example, it is advantageous according to the invention if, in the position of use of the PV system, the posts are aligned substantially vertically and / or the crossbars are aligned substantially horizontally. By aligning the posts and crossbars in this way, it can be ensured in particular that edges of the posts and crossbars aligned with the PV modules, which delimit the individual mounting fields, are preferably arranged at a uniform distance from the outer edges of rectangular PV modules of the PV system. As a result, for rectangular PV modules, which are typical on the market, economical use of material for the supporting structure and / or good use of space can be achieved, since the distance between the posts and crossbars and the PV modules can be selected to be as small as possible.In contrast to conventional PV systems for unifacial PV modules, this avoids the need for posts or bars to run below or behind a PV module, which would result in undesirable shading of the PV modules.

[0018] In addition, in a PV system according to the invention, it can be provided, for example, that several, in particular up to four, PV modules are arranged one above the other in the vertical direction. By providing several rows of PV modules running one above the other, the usable active area can be increased overall without the need to erect additional posts. According to the invention, the provision of more than four PV modules arranged one above the other has the disadvantage that the wind load increases considerably, so that the foundations of the posts have to be designed much more complexly and thus more expensively. Therefore, the invention proposes limiting the number of modules arranged one above the other to four. According to the invention, the optimum number of rows of PV modules arranged one above the other is between two and three.

[0019] According to the invention, it is further preferred if horizontally adjacent PV modules are arranged offset from one another in the vertical direction. This configuration, which is atypical for conventional systems, enables a particularly efficient construction of the supporting structure. This applies in particular when the vertical offset between horizontally adjacent PV modules is at least the height of one bar. This allows bars to be mounted vertically one above the other on the posts, which is advantageous for numerous embodiments of the supporting structure according to the invention. In particular, the respective attachment points of horizontally adjacent bars on a post can thus be arranged vertically one above the other. This enables the efficient use of flanges and straps on the posts, as will be explained in more detail below.

[0020] To ensure the most efficient erection of the PV system posts, the invention provides that the posts are divided at least into the fastening section connected to the ground and the holding section connected to the fastening section. The holding section extends above the fastening section. The advantage here is that the fastening section can initially be anchored in or on the ground independently of the holding section. This is advantageous, for example, if the fastening section is to be anchored by ramming it into the ground. For this purpose, the fastening section can be designed, in particular, in the form of a ramming profile, so that the fastening section has sufficient rigidity for ramming.

[0021] According to the invention, both the holding section and the fastening section can be designed as a longitudinal profile, preferably made of metal. This is advantageous in that different profiles can be combined with one another. For example, a C-, U-, or Z-profile, which is suitable for ramming, can be combined as the fastening section with an S- or Q-profile, which are each less suitable for ramming, as the holding section of the post. Furthermore, it can also be provided that the holding section is weaker than the fastening section in order to save material. This can be achieved, for example, by choosing a different profile, in particular different profile dimensions, or by weakening the material.

[0022] After the foundation of the fastening section has been laid, the holding section can be aligned with the fastening section and firmly connected to it, for example by means of screws with a self-tapping thread that can be screwed into possibly pre-drilled holes. For this purpose, it is preferred according to the invention if corresponding contact surfaces are formed on the fastening section and the holding section. The two sections can abut one another at these contact surfaces and thus overlap. This creates the possibility of compensating for deviations in the height of the fastening section by aligning the holding section with respect to the fastening section. For this purpose, the holding section can be designed to be displaceable along the longitudinal direction of the fastening section, particularly when the contact surface abuts the fastening section.

[0023] According to the invention, the overlap between the fastening and holding sections can additionally be designed to be rotatable. This allows the two sections of a post to be rotated relative to each other when the corresponding contact surfaces are in contact. This can be achieved, for example, by a flat design of the contact surface so that the fastening and holding sections lie back to back when assembled. A rotatable design of the overlap enables the longitudinal axes of the two sections of the post to be rotated relative to each other, thereby achieving improved compensation for skewed alignments of the fastening section that can arise during its foundation.

[0024] According to the invention, it is further advantageous if the individual PV modules, in particular the outer edges of the PV modules, are arranged at a distance from the posts and / or transoms. This is because shading of the active surface of the PV modules by the posts and / or transoms can be avoided. In this case, it is preferred according to the invention if the spacing is selected to be only large enough to exclude shading up to an angle of incidence of a maximum of 75°. This avoids excessive space requirements for the spacing, thus enabling efficient use of space. In general, it is preferred according to the invention if the PV modules are mounted centrally with respect to the outer edges of the posts and / or transoms. This is because minimal shading of both sides of the bifacial PV modules can be achieved.

[0025] The angle of incidence here and below is understood to be the angle formed by an incident sunbeam with a normal to the active surface of a PV module. Thus, perpendicular light incidence onto the active surface of a PV module corresponds to an angle of incidence of 0°. Since the PV modules are arranged vertically, the angle of incidence can, in particular, be a lateral angle of incidence.

[0026] According to the invention, a highly efficient PV system can be achieved if the active surfaces of the PV modules are arranged at a distance from the posts and / or transoms. This largely prevents the posts or transoms from shading the edge areas of the active surfaces of the PV modules when light is incident at an angle, which would negatively impact the system's efficiency.

[0027] According to the invention, it is particularly advantageous if the active surfaces of the PV modules are spaced from the posts in such a way that shading of the active surface by the posts is excluded at least up to an angle of incidence of 20°, particularly preferably at least up to an angle of incidence of 30°. Alternatively or additionally, it can be provided that the active surfaces of the PV modules are spaced from the bars in such a way that shading of the active surface by the bars is excluded at least up to an angle of incidence of 25°, preferably at least up to an angle of incidence of 30° or even 40°.

[0028] An even more compact PV system can be achieved according to the invention by arranging the active surfaces of the PV modules on opposite sides asymmetrically spaced from posts and / or transoms. For example, it can be provided that individual PV modules are spaced from the posts in such a way that, for northern directions, shading of the active surface of the PV module is excluded at least up to an angle of incidence of 20°, preferably at least up to an angle of incidence of 30°, while for southern directions, shading of the active surface of the PV module is excluded at least up to an angle of incidence of 45°, preferably at least up to an angle of incidence of 60°.

[0029] With horizontally running bars, it is sufficient according to the invention if the PV modules are only arranged at a distance from those bars that run above the PV module. This prevents shading of the active area by bars running above. In contrast, for modules arranged above a horizontally running bar, there is no risk of shading by this bar running below the module, since the directly incident sunlight hits the active area obliquely from above. As a result, according to the invention, the active area of ​​a PV module above a horizontally running bar can be moved close to it in order to minimize the space required by the PV system in the vertical direction.

[0030] If the PV system is to be installed in locations particularly prone to wind, the invention can provide for the PV modules to be suspended from the supporting structure so that they can pivot about a rotation axis. It is advantageous if the rotation axis runs approximately parallel to the bars, as this ensures pivoting capability within a compact mounting field. Pivoting the PV modules about a rotation axis can be achieved, for example, by suspending the PV modules so that they can pivot only on the upper bars of the supporting structure. Due to this pivoting capability, the PV modules can move out of the plane formed by the posts in strong winds. The resulting gaps in the mounting fields allow the wind to blow through almost unhindered, significantly reducing the wind load acting on the supporting structure.The advantage here is that the supporting structure as a whole needs to be less stable, so that, for example, the posts can be made less rigid and thus overall material costs can be saved.

[0031] To facilitate the simplest possible installation of the PV system, the invention, as already mentioned, provides for support surfaces on the posts to which a corresponding bar can be flatly attached. Due to the flat contact of a bar against a support surface, the forces and moments introduced by the bar can be effectively absorbed by the post.

[0032] According to the invention, the holding surfaces are designed as flanges on a profile and / or as tabs on an opening, for example, introduced into an outer surface of a profile. For this purpose, it can also be provided that holding surfaces are designed as flanges on one side of a post and as tabs on the other side. Tabs or flanges are therefore considered alternatives according to the invention, whereby it is preferred according to the invention for both tabs and flanges if they protrude at right angles from the post. Furthermore, it is provided that the tabs and the flanges run in the direction of a plane formed by the PV modules and are laterally offset from this plane.

[0033] Furthermore, holes, elongated holes or the like may be provided on tabs and / or flanges to facilitate the fastening of the bars by means of screws or the like.

[0034] According to the invention, a flange serving as a holding surface can, in particular, run along an entire holding section of a post; the flange is thus part of a profile.

[0035] When using profiles that only have simple flanges at their ends, such as an S-profile, additional angle connectors that can be screwed onto the profile can be provided according to the invention. This allows a closed, circumferential force flow to be created when a transom is attached to a simple flange in conjunction with an angle connector, thus increasing the rigidity of the structure. In addition, flanges on posts can also be provided according to the invention solely to increase the flexural rigidity of the posts.

[0036] As already mentioned, the shape of a tab is determined according to the invention by the shape of the corresponding opening in a profile. This can be achieved, for example, by cost-effectively creating the openings and corresponding tabs on the posts using processes such as punching or laser cutting in conjunction with bending or forming. In this case, a pair of tabs can also be formed from one opening, which are arranged on either side of the opening to allow a bolt to be gripped from either side.

[0037] According to the invention, the robustness and rigidity of the supporting structure can be further increased if the holding surfaces are designed in pairs. This is because a pair of holding surfaces can grip a bolt inserted between these holding surfaces on both sides, thus further improving the dissipation of forces. To facilitate the gripping of a bolt on both sides by the holding surfaces, it is also advantageous if the bolts are narrower than the posts, in particular narrower than the distance between pairs of holding surfaces.

[0038] Additionally, it may also be provided to attach transoms to the posts using angle connectors. According to the invention, angle connectors are preferred that have retaining surfaces on both sides of a transom to be attached, which can be connected flatly to a post.

[0039] A further possible embodiment of the invention provides for through-holes to be formed on the posts, each of which accommodates a transom or its end. The provision of through-holes has the advantage that tilting of the posts relative to each other and associated fluctuations in the spacing between the posts can be easily compensated for by inserting the transoms more or less deeply into the through-holes.

[0040] It is understood that for ease of installation, it is advantageous if the through-hole is designed somewhat larger than the transom it accommodates. However, according to the invention, the through-hole can be provided in particular with a vertical height of at least 1.25 times, preferably at least 1.5 times, the height of a transom. This creates the possibility of at least partially compensating for different post heights, for example, in undulating terrain, by mounting the transoms at different heights.

[0041] In contrast to through-channels formed laterally on the outer surfaces of the posts using attached angle connectors, through-holes also offer the advantage that they can be positioned centrally relative to the post. This makes it particularly easy to position the PV modules centrally relative to the posts and / or transoms. Such an arrangement is preferred according to the invention because it minimizes shading on both sides of a PV module.

[0042] When using through-openings, it is particularly advantageous if at least the holding section of the post is designed in the form of an omega profile. This is because when using an omega profile, two horizontally adjacent bars can be gripped on both sides by the two open ends of the omega profile, which can be formed by a parallel pair of flanges running along the profile. This allows a closed flow of forces to be created in the omega profile. Individual bars can be guided through through-openings formed in the side surfaces of the omega profile. With this design, bars running to the left and right of a post designed as an omega profile can be attached to a pair of flanges running on one side of the post. This results in a particularly easy-to-install yet robust design for the supporting structure.

[0043] A similarly robust connection between the mullion and transom using through-holes can be achieved according to the invention if at least the holding section of the mullion is designed in the shape of a C- or U-profile. In this case, through-holes can be formed on the side surfaces of the respective profile, which have bent-up tabs, which in turn provide holding surfaces for mounting transoms.

[0044] If two transoms running to the left and right of a post are to be mounted on a bracket, it is advantageous if the height of the bracket is more than 1.25 times the height of one transom, preferably at least 1.5 times the height of one transom. This design ensures that one bracket, or a pair of brackets, of a through-hole is high enough to hold two transoms. However, an additionally higher through-hole can be useful according to the invention to enable improved compensation of the mounting height of transoms.

[0045] In one embodiment of the invention, through-holes can have one or more tabs, as previously described, which provide holding surfaces for mounting a transom, preferably two transoms. This results in a variety of configurations, even in conjunction with omega profiles. In contrast to angle connectors, which must be attached separately, tabs offer the advantage of reduced installation effort, as they do not have to be attached to the profiles like angle connectors. In addition, bent tabs are usually connected to a vertical surface of a profile in a rotationally fixed manner, thus easily achieving high torsional rigidity of the supporting structure.

[0046] In general, and particularly in all previously described configurations of push-through openings, it can be provided that individual push-through openings have at least twice, in particular at least three times, the height of a transom. This configuration allows one transom, or in particular two transoms, to be placed in a push-through opening, whereby, due to the larger configuration of the push-through opening, the installation height of the transom, or transoms, can be variable with respect to the push-through opening, i.e., can be varied, in particular, during installation. This allows height compensation to be achieved, which is particularly advantageous on undulating terrain.

[0047] As an alternative to accommodating at least two bolts in a through-opening, a further embodiment of the invention provides that only one bolt is placed in a through-opening, while a further bolt is mounted on a side of the post opposite the through-opening without a through-opening and by means of holding surfaces formed on the post. In this case, it can be provided in particular that the bolt guided through the through-opening is mounted on the side of the post opposite the through-opening on the same holding surface as the further bolt. In other words, according to one embodiment of the invention, it can be provided in particular that a bolt inserted through a through-opening and a further bolt are fastened to a holding surface.

[0048] A further embodiment of the invention provides that the posts have a profile with a C-shaped or U-shaped basic shape, at least in the or one of the support sections. Additional support surfaces can be formed as flanges at the ends of the profile. The flanges can either be formed during the production of the profile or subsequently attached to the profile.

[0049] According to yet another embodiment of the invention, the posts can have a profile with a Z-shaped or S-shaped basic shape, at least in the or one of the holding sections, with additional holding surfaces designed as flanges at the ends of the profile. S-shaped profiles are sometimes also known commercially as "Z-plus" profiles. "Additional holding surfaces / flanges" is to be understood here, as previously with the C- or U-shaped profiles, to mean that the basic shape of the profiles is already given without the flanges, even if these are already created during the profile's manufacture.

[0050] For particularly simple yet robust installation of the PV modules, it is preferred according to the invention if the PV modules are fastened to the bars. If modules are mounted in landscape / portrait format, the modules are held along their longer / shorter sides. For this purpose, special holding elements can be provided according to the invention. These holding elements preferably provide groove sections into which an edge of the respective PV module is inserted or can be inserted, preferably without a force-fitting connection. The groove sections can be lined with a plastic or elastic material, preferably EPDM, to protect the PV modules from damage. Furthermore, it can additionally be provided for the PV modules to be glued to the holding elements in order to prevent the PV modules from slipping in the groove sections.

[0051] According to the invention, the retaining elements can be manufactured, for example, as cold-formed steel parts, preferably made of corrosion-resistant steel and / or with corrosion protection, or from plastic or light metals such as aluminum, and in particular have a rubber coating. The retaining elements can also be manufactured in the form of profiles or as injection-molded or die-cast parts.

[0052] According to the invention, the PV modules are preferably held on both sides by the respective holding element in the region of the groove sections, so that a secure holding of the PV modules can be guaranteed.

[0053] It is understood that holding elements as described above can also be used in an analogous application of the invention for fastening PV modules to the posts.

[0054] Particularly preferably, two opposing groove sections are formed on each of the holding elements. Thus, a single holding element can hold two opposing PV modules. It is advantageous if the two groove sections extend in a common plane. Additionally or alternatively, it can also be provided that the two groove sections are each arranged centrally with respect to the lateral outer surfaces of the holding element. Such configurations significantly facilitate central positioning of all PV elements with respect to posts and / or transoms, which is preferred according to the invention.

[0055] Furthermore, it can also be provided that the holding elements each have a preferably rectangular cross-sectional taper. At the point where the cross-section changes, a stop can thus be formed on the holding element. This allows the holding element to be inserted or to be inserted into an opening formed on a bolt up to a defined insertion depth. For this purpose, it can therefore be provided according to the invention that the bolts have through-openings, in particular centrally arranged ones, corresponding to the holding elements. These through-openings on the bolts can in particular be designed in such a way that slipping of the holding elements in the longitudinal direction of the bolt is excluded.

[0056] A key advantage of this design is that, for robust positioning of the PV modules, it is sufficient to attach the retaining element in the area of ​​an upper groove to the bar that receives the retaining element, for example, by means of a screw connection; additional fastening in the area of ​​the second, lower groove is therefore unnecessary. This not only saves assembly effort, but also allows the retaining elements to be designed narrower in a respective lower area surrounding a lower retaining groove than in an upper area, which is advantageous for avoiding shading of the PV modules.

[0057] For a positionally secure and tilt-free mounting of the holding elements, it is also advantageous according to the invention if a contact surface is formed on the holding element with which the holding element rests flatly against the bolt.

[0058] A further optimization of the holding elements according to the invention provides that they have a bevel on a bottom side so that shading of a PV module that is inserted into a lower groove of the holding element can be avoided.

[0059] As an alternative or supplementary design to separate retaining elements, the invention provides for groove sections to be formed on the bars, into which a respective PV module can be inserted. These grooves can, for example, also be formed only on the upper side of a bar and / or, in particular, extend over the entire length of a bar. The advantage here is that the PV modules can be inserted directly into the grooves of the bars during assembly, thus reducing the number of retaining elements to be installed. This approach can reduce assembly effort and thus save costs.

[0060] Similar to the retaining elements, the bars can also be provided with a beveled underside. This ensures large angles of incidence even for the edge areas of the active surface of the PV module without being shadowed by the respective bar.

[0061] The invention further recognizes that it can be advantageous to design the support structure in such a way that cultivation, particularly agricultural cultivation, of the area on which the PV system is to be installed, in particular of cultivation spaces between individual rows, remains possible. To this end, the invention provides for a free space to be maintained between the ground and a lowest bar of the support structure. According to the invention, this free space can be at least 50 cm, preferably at least 60 cm, and particularly preferably at least 1 m high. It is understood that the free space is thus interrupted only by the necessary posts.

[0062] When installing the PV modules in rows, it can be provided in particular that the rows of the PV system are spaced apart in such a way that there is a cultivation space with a width of at least 6 meters, at least 8 meters or at least 10 meters between the rows.

[0063] For the most efficient use of space, i.e. in particular for maximum energy generation per area, it can be advantageous according to the invention if the PV modules essentially form a plane with the supporting structure. Accordingly, the posts can be arranged along a substantially straight line. From a certain minimum width of the installation area, the PV modules can also be arranged in several rows. In this case, it is advantageous if these rows are arranged at a distance from one another, preferably evenly. This is because, depending on the height of a row of the PV system, a minimum distance from a neighboring row in the direction of the sun can be selected according to the invention in such a way that shading of the active surfaces of the PV modules by the neighboring row is largely excluded. Rows of different heights, for example with a different number of PV modules arranged one above the other, can also be provided.

[0064] In a particularly advantageous embodiment of the invention, the PV modules can be oriented essentially in a north-south direction. With a north-south orientation, the surface normals of the two active sides of a bifacial PV module are each oriented east and west. According to the invention, angular deviations of + / -30° can be provided, which is why the orientation is described as "essentially" running in a north-south direction. Such configurations allow the PV system to achieve a current-daily curve characteristic as described above, which exhibits no peak power around midday. However, PV systems according to the invention can be advantageously used in a variety of other orientations relative to the cardinal direction.

[0065] According to the invention, the area utilization of the PV system can be optimized with acceptable losses in energy conversion efficiency if the distance between two rows is at least three times, preferably at least four times, and particularly preferably at least five times the maximum height of an active area of ​​the PV system. Depending on the geographical latitude of the PV system's installation location, this largely prevents shading of PV modules by a neighboring row, particularly in the morning and evening. The maximum height of an active area of ​​the PV system can be defined, for example, by a vertical distance between a highest and a lowest point, each within the active areas of a row of the PV system (see also the description of the figures).

[0066] Shading is known to be detrimental because the individual cells of a PV module are typically connected in series to form cell strings, meaning that the least exposed cell limits the actual current flow. While bypass diodes are known in the art and are standardly included in PV modules to minimize the effects of partial shading of the active area of ​​a PV module, the exclusive use of bypass diodes to minimize the effects of shading is associated with significant disadvantages. For example, significant heat generation occurs whenever a bypass diode switches on to electrically bridge a shaded area of ​​an active area.However, such an approach is unacceptable, especially for PV systems as defined in the invention, where daily shading is to be expected, as frequent heat generation can negatively impact the service life of the PV modules. A further disadvantage is that many inverters on the market, despite the presence of bypass diodes, set an operating point that is unfavorable for the PV module, resulting in further power losses in the PV modules connected to the affected inverter.

[0067] A PV system according to the invention, in particular as described above and / or according to one of the claims directed to a photovoltaic system, can be used such that the PV modules are oriented approximately in a north-south direction during power generation. According to the invention, angular deviations of + / -30° can be provided, which is why the orientation is described as running "approximately" in a north-south direction. With a north-south orientation of a PV module, the surface normals of the two active sides of a bifacial PV module are oriented to the east and west, respectively. Through this specific use, a PV system according to the invention can achieve a current-daily curve characteristic as described above, which exhibits no peak power around midday.

[0068] The invention will now be described in more detail using exemplary embodiments, but is not limited to these exemplary embodiments.

[0069] Further embodiments result from combining the features of individual or multiple claims with each other and / or with individual or multiple features of the respective embodiment. In particular, developments of the invention can thus be derived from the following description of a preferred embodiment in conjunction with the general description, the claims, and the drawings.

[0070] It shows: Fig. 1 a dimetric view of a photovoltaic system according to the invention, Fig. 2 a detailed view of a row of posts of the same PV system, Fig. 3 a post according to the invention designed by means of a C-profile with two mounted bars, Fig. 4 a post according to the invention designed by means of an omega profile with two mounted bars, Fig. 5 a post according to the invention designed by means of an S-profile with two mounted bars, Fig. 6 a bar according to the invention with two opposing groove sections for receiving two PV modules, Fig. 7 a cross section through a holding element according to the invention which is inserted into a bar formed by a U-profile, Fig. 8 a perspective view of the holding element from Fig.7, inserted into the U-shaped bar, Fig. 9 a plan view of a post and PV modules asymmetrically spaced from it in the north and south directions according to the invention, as well as their active areas, Fig. 10 a lateral cross-sectional view of a horizontally running bar and PV modules arranged above and below it and their active areas, Fig. 11 a side view of a PV system according to the invention with two rows of posts that are set up at a distance from each other.

[0071] In the following description of various embodiments of the invention, elements that correspond in their function are given the same reference numbers even if they have a different design or shape.

[0072] The Figure 1shows a photovoltaic (PV) system, designated as a whole by 1, with several bifacial PV modules 2 arranged upright on a support structure 3. The support structure 3 is formed by several posts 4 arranged in a row. More precisely, each post 4 is divided into a fastening section 7 and a connected support section 8. As indicated by the horizontal surface, which illustrates the earth's surface, the support structure 3 is anchored in the ground by means of the fastening sections 7.

[0073] As the Figure 1 shows, several bars 5 run essentially horizontally between the posts 4. Since the posts 4 are mounted essentially vertically, two adjacent posts 4 and two adjacent bars 5 define an essentially rectangular mounting field 6. In the Figure 1In the embodiment shown, a PV module 2 is arranged vertically in each of these rectangular mounting fields 6. The upright arrangement of the PV modules 2, which have active surfaces 9 on both sides, makes it possible to efficiently capture sunlight from western and eastern directions and convert it into electrical current using the PV system.

[0074] As the detailed view of PV system 1 in Figure 2 shows, several PV modules 2, namely exactly two, are arranged one above the other in the vertical direction. In addition, Figure 2It is clearly visible that, for example, the uppermost bars 5 are arranged offset from one another in the vertical direction. Since the PV modules 2 are attached to the bars 5 by means of holding elements 15, horizontally adjacent PV modules 2 are also arranged offset from one another in the vertical direction. This configuration is preferred according to the invention because it allows for easy compensation of different terrain profiles.

[0075] As with regard to Figure 2As can be clearly seen, the fastening sections 7 and the holding sections 8, each formed by C-profiles, lie back to back and thus overlap in an overlapping area. According to the invention, it is preferred if the overlapping area is located above the ground, as this facilitates the installation of the holding section 8 to the fastening section 7 and, moreover, the fastening section 7 can be anchored in the ground independently of the holding section 8, e.g., by ramming.

[0076] The Figure 3 shows an inventive embodiment of a connection of a post 4, more precisely its upper holding section 8, with two horizontally extending bars 5. While the bars 5 are each formed by a U-profile 22, the holding section 8 of the post 4 is formed by a C-shaped profile 12.

[0077] To fix the two bars 5, the post 4 is Figure 3an opening 14 designed as a push-through opening is provided through which the bars 5 are inserted. The opening 14 itself is created by punching on the C-profile 12 of the post 4. By means of a punching process, the two Figure 3 illustrated tabs 13, which serve as holding surfaces 10 according to the first alternative of claim 1. For example, the two bars 5 can be attached to the two tabs 13 very easily and at a variable height by means of screws with self-tapping threads and correspondingly drilled holes.

[0078] The Figure 4shows an alternative embodiment of the holding surfaces 10 according to the invention, which follows the second alternative of claim 1: For this purpose, the post 4, more precisely its upper holding section 8, is designed by means of an omega profile 12. At its two free ends, the omega profile 12 has two flanges 11, which, unlike the tabs 13 in Figure 3, run along the entire length of the omega profile 12 and can be used advantageously as retaining surfaces 10 according to the invention. Thus, the left bar 5 is merely inserted into the omega profile 12, while the right bar 5 is guided through a through-opening 14 formed in a side surface of the post 4. As can be clearly seen, both bars 5 can be fastened one above the other to the paired retaining surfaces 10 of the omega profile 12. By designing the retaining surfaces 10 in pairs, each on both side surfaces of a bar 5, a particularly stable connection and thus a particularly stable supporting structure 3 can be achieved. Fig. 4 shows, the holding surfaces 10 designed in pairs grip the bars 5 on both sides.

[0079] Both from Figure 3 as well as from Figure 4The advantage of the inventive design becomes apparent, which provides that the bars 5 are narrower than the posts 4. This design makes it much easier for the bars 5 to be guided through the through-openings 14 of the posts 4 and at the same time to be held by the holding surfaces 10 formed on the posts 4 on both sides, i.e. in particular from the outside as in Fig. 4 , are taken.

[0080] The Figure 5 shows yet another embodiment of a connection according to the invention between two bars 5 and a post 4, in which features of the second alternative of claim 1 are also implemented: The post 4 in Figure 5 is designed as an S-shaped profile 12. This profile has only one flange 11 at each end, to which the bars 5, as shown in Figure 5shown, can be attached flatly. This design has the advantage, on the one hand, that no through-holes 14 have to be formed in order to attach bars 5 running to the left and right of the post 4 to the same. On the other hand, however, an S-shaped profile 12, which in the prior art is sometimes also referred to as a "Z" or "Z+" profile, does not offer a pair of flanges 11 on the left and right, as is the case at least on one side with the Figure 4 This is the case with the omega profile 12 shown. However, according to the invention, even with an S-profile, holding surfaces 10 can be formed on both sides of a bar, i.e. in pairs, for example by attaching additional flanges 11 or angle connectors known per se to the S-profile 12.

[0081] According to the invention, either two bars can be placed in a through-opening 14, as shown in Figure 3illustrated, or just a bar, as the embodiment of the Figure 4 shows. How Figure 4 shows, a further bolt 5 adjacent to a first bolt 5 placed in a through-hole 14 can thus be mounted on a side of the post 4 opposite the through-hole 14, without using a through-hole 14, namely by means of holding surfaces 10 formed on the post, which in Figure 4 formed by the flanges 11. Such a design is very useful, for example, to compensate for different heights in uneven terrain.

[0082] The Figure 3 The embodiment shown can be interpreted as meaning that the post 4, at least its holding section 8, is formed by a profile 12 with a C-shaped or U-shaped basic shape. Preferably, the flanges 11, which are intended to serve as holding surfaces 10, are as shown in Figure 4formed, ie the flanges 11 run in the direction of the bars 5. This design enables the bars 5 to lie flat.

[0083] The Figure 4 The omega profile 12 of the post 4 shown can in turn also be understood as a profile 12 with a C-shaped basic form, wherein the holding surfaces 10 shown are designed as flanges 11 at the ends of this profile 12.

[0084] In an analogous manner, the Figure 5 The post 4 shown, more precisely its upper holding section 8, can be understood as being formed by a profile 12 with a Z-shaped or S-shaped basic shape, wherein here too additional holding surfaces 10 are designed as flanges 11 at the ends of the profile 12.

[0085] As already mentioned in the Figure 2 As indicated, the PV modules 2 are preferably fastened to the bars 5 according to the invention, for which purpose the Figure 2 shown holding elements 15 can be provided.

[0086] The Figure 6 shows an alternative embodiment according to the invention, in which groove sections 16 are provided on the bars 5 for receiving and holding the PV modules 2. As in Figure 6 As shown, it is generally preferred according to the invention if groove sections 16 are opposite one another and / or lie in a common plane. This design allows the PV modules 2 to be aligned centrally with respect to the supporting structure 3. This can be clearly seen in Figure 6 are also the bevels 24 according to the invention on the underside of the bar 5. These bevels 24 minimize the shading of the lower PV module 2 by the bar 5.

[0087] Figure 7shows a detailed cross-sectional view through a holding element 15 according to the invention. The holding element 15 is inserted into a through-opening 23 formed on an underside of the bar 5, which is formed by a U-shaped profile 22. A contact surface 18 is formed on the holding element 15, with which the holding element 15 rests flat against the inside of the bar 5. The cross-sectional tapering 17, which is formed at the level of the contact surface 18, ensures that the holding element 15 can be inserted into the through-opening 23 up to a defined insertion depth. This ensures, among other things, that the active surfaces 9 of the two PV modules 2 can be mounted at a defined distance from the bar 5, so that, in particular, shadowing can be efficiently avoided. How well in Fig. 7As can be seen, the edges of the PV modules 2 are each inserted into the two opposing groove sections 16 of the holding element 15. The insertion depth is selected such that the active surfaces 9 of the PV modules 2 are not covered or shaded by the holding element 15 and / or the bar 5 up to a certain angle of incidence.

[0088] The features of the holding elements 15 according to the invention just explained are also clearly shown in the perspective view of the Figure 8 In particular, Figure 8 It can be seen that the holding elements 15 preferably grip the PV modules 2 on both sides to ensure secure mounting. For this purpose, it is sufficient if the holding elements 15 grip the PV modules only along a specific edge section on both sides, as shown in Figure 8 shown.

[0089] The Figures 9 and 10illustrate another central aspect of the present invention, namely arranging the active surfaces 9 of the PV modules 2 at a distance from the posts 4 and / or bars 5. As the plan view of the post 4 in Figure 9 shows, the active surfaces 9 of the two PV modules 2 arranged to the left and right of the post 4 are spaced from the post 4 in such a way that sunlight can reach the active surface 9 up to a certain angle of incidence without being shaded by the post 4. The angle of incidence corresponds in Figure 9 exactly the angle that the two sun rays shown make with the plumb line (horizontally running in Fig. 9 ) of the active area 9 in question.

[0090] If one looks more closely at the two opposite sides of the two PV modules 2, it is noticeable that the active surfaces 9 to the left and right of the post do not have the same distance from the post 4. Rather, they are arranged asymmetrically. Due to the slightly larger distance of the active surface 9 of the Figure 9 The PV module 2 arranged at the top ensures that shading of the active surface 9 for sunlight from southern directions is excluded for larger angles of incidence than is the case for the Figure 9 The PV module 2 arranged below is for sunlight from northern directions. In other words, at the southern edge of a PV module 2, the distance between the PV module 2, more precisely its active area 9, and the post 4 is chosen to be slightly larger than at its northern edge, as is the case for the two PV modules 2 in Figure 9 illustrate.

[0091] The Figure 10shows how shading of the active surfaces 9 can be prevented by spacing the active surfaces 9 of the two PV modules 2 shown from the transverse bar 5 according to the invention. Figure 10 represents a cross-section through a horizontally extending bar 5, the sunbeam shown falls diagonally from above and usually from the side onto the lower PV module 2. By spacing the active surface 9 of the lower PV module 2 from the bar 5, as in Fig. 10 shown, a maximum angle of incidence is defined up to which sunlight can hit the active surface 9 without shadowing. In the Figure 10 This angle of incidence would correspond exactly to the angle formed by the projection onto the vertical section plane of the Figure 10 The incident sunbeam shown in the figure is directed vertically onto the active surface 9 (horizontally in Figure 10). It is therefore clear that the actual angle of incidence between the sunbeam and the incidence slot can usually be larger than the angle that the (in Figure 10 illustrated) projection of this ray in the plane of intersection with the normal of incidence.

[0092] In the rare event that the Fig.10 If the incidence line of the active surfaces of the PV modules shown pointed straight towards the sun, the Fig. 10 The angle of incidence illustrated by the sunbeam corresponds to the position of the sun, i.e., the height of the sun above the horizon measured in degrees. However, sunlight usually hits the PV modules at an angle from the side, so the position of the sun and the angle of incidence deviate from each other. The two Figure 9 The sun rays shown fall obliquely from the side onto the PV modules 2, whereby here too projections of these rays are made into the horizontal section plane of the Figure 9are shown.

[0093] Even with the Figure 10 In the exemplary embodiment shown, an asymmetrical spacing of the PV modules from the bar 5 could be provided according to the invention. For example, it would be advantageous according to the invention to move the upper PV module 2, or more precisely its active surface 9, closer to the bar 5. This would, on the one hand, reduce the maximum construction height of the supporting structure 3 and thus the effective wind load; on the other hand, shading of the upper active surface 9 by the bar 5 below can be ruled out, since sunlight always falls onto the PV modules 2 from an angle above. According to the invention, the upper PV module 2 could therefore be moved close to the bar 5 until the active surface 9 is just not yet covered by the bar 5.

[0094] The Figure 11Finally, further embodiments of the photovoltaic system 1 according to the invention are explained, in particular the spacing of the rows 20 of the PV system 1 according to the invention. As already described in the Figures 1 and 2 As illustrated, the PV modules 2 can essentially form a plane with the supporting structure 3. For efficient use of space, the PV modules 2 are arranged as shown in Figure 11 shown, arranged in spaced-apart rows 20. The PV modules 2 of a row 20 thus also essentially form a plane, whereby this plane can be oriented in particular in a north-south direction, as shown in Fig. 11 This means that, for example, if a sunbeam comes from the west (coming from the left in Figure 11 ) which in Figure 11The situation shown may occur, i.e. a partial area of ​​a row 20 (here the lower PV modules of the right row 20) is shaded by a neighboring row 20 (here the left row 20).

[0095] As through the two sunbeams in Figure 11 As indicated, the shading increases the lower the sun is. Therefore, a Figure 11 The embodiment shown is preferred, in which the distance designated B between the two rows 20 is more than three times the maximum height of an active area 9 of the PV system 1. This maximum height corresponds in Figure 11 exactly the vertical distance A, which defines the distance between a highest and a lowest point, each within the active areas 9 of the left row 20. Due to the large horizontal distance B between the two rows 20, as inventively chosen, it is thus, like the upper sunbeam in Figure 11shows, ensures that even when the sun is low, only a part of the right row 20 is shaded, so that at least the upper active surfaces 9 of the right row 20 are in Figure 11 can continue to be used to generate electricity.

[0096] A further advantage of the spacing of the rows 20 of the PV system 1 is the cultivation space 19 that is created between the rows, as this can be used for agricultural purposes, for example. For this purpose, the invention provides in particular for Figure 11 to make the cultivation space 19 designated with a width B usable by maintaining a free space 26 in each row between the posts 4 and between the lowest bar 5 of the supporting structure 3 and the ground surface. Because the PV modules 2 are thus arranged at least at a height C above the ground (cf. Fig. 11), on the one hand, damage to the same caused by rockfall during agricultural use of the open space 19 can be avoided. On the other hand, this design largely protects the lower active areas 9 of the PV system from being shaded by vegetation or plantings in the open space 19. The open space 26 thus creates the necessary conditions for agricultural use of the open space 19 without any significant loss in electricity production.

[0097] Based on the Figure 11 The advantages of dividing the PV system into superimposed electrical rows 21 can also be understood. Because the lower row 21 of the right row 20 is Figure 11 electrically from the upper row 21 of the right row 20 in Figure 11separated, ie in particular each assigned to a separate inverter input, the shading of the lower row 21 cannot affect the current produced by the upper row 21. In an analogous manner, Figure 11 The effect of partial shading of the upper PV module 2 of the right-hand row 20 can be minimized according to the invention in that this PV module 2 has two horizontally extending and superimposed electrical rows, formed for example by two electrically separated active surfaces 9 within the PV module 2.

[0098] In summary, for the economical and energy-efficient use of a PV system 1 with upright, in particular bifacial, PV modules 2 and in particular for the extensive avoidance of shading of the PV modules 2, on the one hand a very easy to manufacture and assemble support structure 3 is proposed, which is constructed by vertical posts 4 and horizontally extending bars 5 connected to one another at intersection points, so that rectangular mounting fields 6 can be provided for the individual PV modules 2, wherein the posts 4 and bars 5 can each be formed in a material-saving manner by common profiles 12, 22 and wherein in particular a division of the posts 4 into two interconnectable sections 7, 8 makes assembly overall considerably easier. Reference sign list

[0099] 1Photovoltaic system 2PV module 3Supporting structure 4Post 5Bar 6Mounting field 7Fastening section 8Holding section 9(upper) active surface 9'(lower) active surface 10Holding surfaces 11Flange 12Profile of 4 13Tab 14Opening, in particular push-through opening, of 4 (for 5) 15Holding elements 16Groove section 17Cross-sectional taper 18Contact surface 19Management space 20Row 21Electrical row 22Profile of 5 23Opening, in particular push-through opening, of 5 (for 15) 24Bevel 25Axis of rotation 26Free space

Claims

1. Photovoltaic (PV) system (1), having - a plurality of bifacial PV modules (2) that are arranged upright on a supporting structure (3), - wherein the supporting structure (3) has several posts (4) that are attached, in particular anchored, to or in the ground, - wherein crossbars (5) are attached to the posts (4), which crossbars (5) connect two neighboring posts (4) to one another in each case, - wherein two posts (4) and two crossbars (5) in each case define a substantially rectangular mounting field (6), in which at least one PV module (2) is arranged, - wherein the posts (4) are configured in the form of longitudinal profiles (12), - wherein the posts (4) are divided into at least one fastening section (7) connected to the ground and a holding section (8) connected thereto and extending above the fastening section (7), and - wherein holding surfaces (10) are formed on the posts (4), to which holding surfaces an associated crossbar (5) can be attached over a large area, characterized - in that the crossbars (5) are narrower than the posts (4) and are arranged centrally with respect to the posts (4), - in that the holding surfaces (10) - are formed as flanges (11) on one of the longitudinal profiles (12), wherein the respective flange (11) extends along the entire holding section (8) of the post (4) and is part of the longitudinal profile (12) and / or - are formed as tabs (13) on respective openings (14) of the longitudinal profiles (12), wherein the respective shape of a tab (13) is predetermined by the shape of the associated opening (14) in the respective longitudinal profile (12), and - in that the flanges (11) and also the tabs (13) extend in a direction and laterally offset to a plane that is formed by the PV modules (2) and - in that respective outer edges of the respective post (4), which extend in the longitudinal direction of the post (4), are spaced further from the said plane of the PV modules (2) than the respective flange (11) or the respective tab (13).

2. Photovoltaic system (1) according to one of the preceding claims, - wherein the posts (4), at least in an upper holding section (8) of the post (4), have a profile (12) with a Z-shaped or S-shaped basic form and - wherein holding surfaces (10) are formed as flanges (11) at both free ends of the profile (12).

3. Photovoltaic system (1) according to one of the preceding claims, wherein the posts (4) are aligned substantially vertically and / or the crossbars (5) are aligned substantially horizontally and / or - wherein a plurality of PV modules (2), in particular up to four, are arranged one above the other in the vertical direction.

4. Photovoltaic system (1) according to one of the preceding claims, wherein horizontally adjacent PV modules (2) are arranged offset from one another in the vertical direction.

5. Photovoltaic system (1) according to one of the preceding claims, wherein active surfaces (9) of the PV modules (2) are arranged at a distance from the posts (4) and / or crossbars (5), in particular in such a way that shading of the active surface (9) by posts (4) is excluded at least up to an angle of incidence of 20°, preferably at least up to an angle of incidence of 30°.

6. Photovoltaic system (1) according to one of the preceding claims, wherein the active surfaces (9) of the PV modules (2) are arranged on mutually opposite sides, asymmetrically spaced apart from the posts (4) and / or crossbars (5), and / or - wherein the PV modules (2) are pivotably suspended from the supporting structure (3) about an axis of rotation (25) which extends preferably approximately parallel to the crossbars (5).

7. Photovoltaic system (1) according to one of the preceding claims, wherein the holding surfaces (10) are formed in pairs in order to engage on both sides a crossbar (5) inserted between the holding surfaces (10) on both sides, and / or - wherein the crossbars (5) are narrower than the posts (4), in particular narrower than a distance between holding surfaces (10) formed in pairs.

8. Photovoltaic system (1) according to one of the preceding claims, wherein push-through openings (14) are formed on the posts (4) in order to receive in each case a crossbar (5) or the end thereof.

9. Photovoltaic system (1) according to claim 8, wherein two crossbars (5) are placed in a push-through opening (14) or only one crossbar (5) is placed in a push-through opening (14), while a further crossbar (5) is mounted on a side of the post (4) lying opposite the push-through opening (14) without a push-through opening (14) and by means of holding surfaces (10) formed on the post (4), - in particular wherein a crossbar (5) inserted through a push-through opening (14) and a further crossbar (5) are fastened to a holding surface (10).

10. Photovoltaic system (1) according to one of the preceding claims, wherein the PV modules (2) are attached to the crossbars (5), wherein holding elements (15) are provided for this purpose, - preferably wherein the holding elements (15) provide groove sections (16) for this purpose into which an edge of the respective PV module (2) is inserted or can be inserted, - particularly preferably wherein a holding element (15) has two opposing groove sections (16) and / or that the crossbars (5) have a bevel (24) on an underside.

11. Photovoltaic system (1) according to claim 10, wherein the holding elements (15) each have a cross-sectional taper (17), so that a holding element (15) can be inserted or is inserted into a push-through opening (14) formed on a crossbar up to a defined insertion depth, - in particular wherein a contact surface (18) is formed on the holding element (15), with which the holding element (15) rests flat against the crossbar (5).

12. Photovoltaic system (1) according to one of the preceding claims, wherein a free space (26) is kept free between the ground and a lowermost crossbar (5), - in particular wherein the free space (26) has a height of at least 50 cm, at least 60 cm or at least 1 m, - in particular wherein rows (20) of the PV system (1) are arranged at such spacings that a servicing space of at least 6 meters, at least 8 meters or at least 10 meters in width is present between the rows (20).

13. Photovoltaic system (1) according to one of the preceding claims, wherein the PV modules (2) and the supporting structure (3) substantially form one plane and / or - wherein the PV modules (2) are arranged in a plurality of rows (20) spaced apart from one another, wherein the PV modules (2) of one row (20) substantially form one plane.