Design and method of fixing and placement of a photovoltaic (PV) system

Abstract

A photovoltaic system, suitable for installation on a base such as a roof, comprising several panels with solar cells and / or support structures for attaching solar panels (1); it is characterized by the fact that the panels and / or structures form a structural part of the system. In this way, the lateral edges (2) of the solar panel can form part of the spatial lattice structure. Thus, it is possible to construct a system that can consist of a large number of connected solar panels which, through the addition of tension / push elements (3, 4), create a spatial lattice structure. With this lattice structure, the system is self-supporting, thereby reducing the load on the base.

Description

Design and method of fixing and placement of a photovoltaic (PV) system Field of invention The invention relates to a design for connecting and supporting photovoltaic (PV) panels. The design also relates to a mechanism and method for fixing the PV panels. Background of the invention Similar designs exist where the panels are connected to each other via a lower beam that, mechanically or using additional ballast, creates a foundation for the individual PV panels. Generally, the panels are attached to the support structure in the final step and connected via plugs for electrification of the PV system. Since modern solar or PV panel systems must withstand wind and snow loads, additional ballast is typically added to prevent uplift and displacement. The significant dead weight and additional loads create a major problem for various types of foundations, such as roofs and other footings, which are not designed to support this extra load and may require reinforcement. Another disadvantage of the current system is the installation time required to assemble the various components on the roof. In addition to the physical effort required by the heavy components, this results in a long installation time and high costs, as these structures are labor-intensive. Although most panels have a dead weight of less than 25 kg to comply with health and safety regulations, lifting these large panels, which weigh 25 kg, in windy conditions is not ideal. Furthermore, errors can easily occur during the wiring and transmission process, as this is carried out on the roof under variable weather conditions. Potential connection errors and fire safety obviously depend on the installer's skill, as they perform multiple repetitive tasks, increasing the risk of human error. Japanese patent publication JP 2005101103 discloses a solar cell device having several solar panels connected vertically to a zigzag structure. The height of the vertical zigzag structure is variable, and this variation in height results in a change in the elevation angles of the light-receiving sections of the individual solar panels. The vertical zigzag solar panel assembly is fixed to a pedestal that allows it to rotate around a vertical axis, thereby influencing the direction it faces toward the light-receiving sections of the individual solar panels. European patent application EP 2843320 A1 discloses a module carrier for several collector modules, such as solar or heat storage modules, arranged in series and aligned at a specific angle. The module carrier is a foldable system in which the connecting elements are attached substantially to the mid-side of the collector modules. All connecting elements are designed to withstand tensile forces, as they all comprise a swivel joint. Chinese patent application CN 108418533 A discloses a quick-release frame that can be mounted on a car roof to provide a vehicle solar device. The lower part of the frame is provided with several magnetic anchors, while the upper part is provided with a solar cell panel assembly. The solar cell assembly is foldable by means of return and torsion springs (9, 10), providing a flexible structure when deployed. Brief description of the invention Thus, the invention aims to provide a design that does not have the aforementioned disadvantages, or at least partially eliminates them, while at least partially retaining its advantages. Furthermore, the invention aims to offer a design and operating principle that simplifies the installation of solar panels, requires fewer operations, and allows for functional checks and quality tests to be performed in a workshop. At least one of these and / or other objectives is achieved with a PV system according to claim 1. In this way, the lateral edges of the panels or frames can be connected to the system, both to the lower and upper beams, using connecting elements capable of withstanding tensile and compressive forces. Due to the way in which a lattice space frame is created, the solar panels or frames form part of a lightweight, self-supporting, bending-resistant space frame. In this way, the panels and / or frames can be connected to each other (with hinges). This allows for easy extension and deployment, eliminating the need to transport and assemble each panel individually, and allowing electrical connections to be installed beforehand. This can therefore save considerable installation time. Furthermore, since the structure is at least partially self-supporting, the load on the roof can be limited. Additionally, the panels and / or frames can have two overlapping side edges, with the system comprising at least two end panels or frames and possibly several intermediate panels and / or frames. The intermediate panels and / or frames of a first side edge may or may not be hinged to a subsequent panel or frame, while the end panels or frames are simply connected to the first or second side, either to the preceding or following panel or frame. With this configuration, the system can be fully electrically wired and is easy to deploy. Therefore, installing the PV system is less physically demanding for installers. The PV system can be configured in both folded and unfolded positions, and in the unfolded position, the panels and / or frames can be angled towards adjacent panels and / or frames. Since the invention can be easily folded and unfolded, is portable, and remains compact in its folded state, the PV system can be easily installed and removed later (e.g., for maintenance or to prevent hail damage). The panels and / or frames may be alternatively provided with sliders, rollers or wheels on a first side edge or on a second side edge. Furthermore, the panels and / or frames can be provided, alternatively on one or the other side, with elements that can be loaded primarily under tension and / or pressure. These elements, implemented, for example, using rods or cables, form a connection from the first lateral edge of the first panel or frame to the second lateral edge of an adjacent panel or frame. The system can utilize rails or guides installed in the foundations, along which sliders, wheels, or rollers can move. As a result, both the surface pressure on the foundation and the frictional resistance during deployment are reduced, leading to deployment with less effort. In this way, the side edge of the solar panel can form part of a space frame structure. This allows for the creation of a system consisting of a large number of interconnected solar panels that, by adding elements capable of withstanding tensile and compressive loads, form a space frame structure. With this lattice structure, the system has a (self-)supporting function, thus reducing the load on the foundations. The invention relates specifically to the addition of tension-compression elements at the top of the lateral edges of solar panels, creating a space lattice structure. This lattice structure provides additional flexural strength or flexural rigidity to the PV system against wind, water, and snow loads. This addition allows for the creation of a span of the space lattice structure from support point to support point. Typically, a foundation's support structure has points or locations where additional loads can be applied, such as on a roof near purlins, walls (sides), or support columns, but the bearing capacity of the intermediate foundation is insufficient. Since the lattice structure does not require additional support points, it can bridge the load-bearing points of the foundation.If the support points are chosen correctly, the upper tension and compression elements are loaded exclusively in tension and the cross section can be drastically limited and / or replaced by a "tension-only" element such as a cable. The invention also allows for the creation of a bending-resistant connection perpendicular to the PV system. This extends the load-bearing capacity of the PV system by distributing the load between multiple PV systems (connected in parallel). The support characteristic of the PV system results in the unloading of weak sections of the foundations and prevents the need in certain locations for a greater total weight of the PV system and / or anchoring to the foundations to prevent the lifting of the PV system by the upward forces of the wind. Brief description of the figures The invention will be explained in more detail by means of the embodiments depicted in the drawing. The drawing shows it: Figure 1 schematic side view of a first embodiment of the invention; Figure 2 a schematic side view of a first embodiment of the invention in a nearly unfolded and unfolded condition; Figure 3 schematic perspective view of a row of a first embodiment of the invention Figure 4 schematic top view of the system in various embodiments (FV horizontal, FV vertical) Figure 5 a first embodiment of the invention in the "folded" position when it is prefabricated and delivered Figure 6 side view with a detail of the hinged connection line on the upper side of the system according to an embodiment of the invention Figure 7 Side view embodiment of the invention with a detail of the hinged connection line on the lower side of the system where a tension-compression rod will be connected and, in most embodiments, also a wheel and a rail Figure 8 Schematic top view of the connected system according to an embodiment of the invention Figure 9 Bottom spatial view of the structure according to an embodiment of the invention Detailed description of the invention It should be noted that the drawings are merely a schematic representation of preferred embodiments of the invention. The drawing should not be construed as limiting the invention. Identical or corresponding components are indicated in the figures with their respective part numbers. The phrase "a PV system" or solar cell system used in this specification and / or conclusions should be interpreted, however, as in no way limited to an array or collection of solar panels or frames on which the solar panels are to be installed, thus whether or not the system is already equipped with electrical connections and cables. The terms "rigid," "structurally load-bearing," or "(self-)supporting" used in this specification and / or conclusions should be interpreted, however, as not being limited to those elements of a structure that can bear some of the forces and / or loads of the structure. This, for example, can increase the stiffness and / or strength of the structure. These forces may include tensile forces, compressive forces, torsional forces, shear forces, and / or other forces that may be significant for structural integrity. The term "roof" or "roof structure" used in this specification and / or conclusions should be interpreted as, but in no way limited to, a (flat) roof, but may also be a (non-load-bearing) foundation. The terms PV panel and solar panel are synonymous and are used interchangeably. The term PV system or PV installation also refers to a connection of PV systems with at least 2 panels. Figure 1 shows a side view of the lattice structure of the photovoltaic system on a roof. Connecting the PV solar panels (1) on both the top (3) and bottom (4) sides using tension-compression members creates a space lattice structure. The side edges (2) of the PV panels (1) form part of this lattice structure. The tension or compression members on the upper side (3) and lower side (4) are connecting members. These members are primarily loaded in tension or compression and may be hinged. If the member is only loaded in tension, the moment of inertia of the cross-section can be kept small, or a cable can be used. Due to the (self-)supporting nature of the truss structure, it only needs to be connected to the foundation with a limited number of support points (10). These support points can be either a bearing point or a mechanical fastening, such as a bolt and screw connection through the top of the roof (roof anchor). The location of these support points (10) can be chosen, for example, at the top of or near a load-bearing point (13), so that the weak foundation (12) is not loaded or is only partially loaded. In this configuration, the advantage is that the roof or foundation, which usually have insufficient load-bearing capacity, can still be provided with a PV system.Additional loads, such as self-weight, wind, and snow in the PV system, are not transferred through the weak section of the roof (12), but through the load-bearing points (13). The load-bearing points of a roof are, for example, purlins, walls (sides), or support columns. Figure 2 shows the system's deployment using hinged connection points (5) between the solar panels, thus positioning the rotation preferably outside the panel's thickness. This allows the panels to fold against each other. These hinge points are located on both the top and bottom sides of the panel. The tension or compression element on the bottom side (4) is hinged at its center, creating a joint that defines the final position and the angles alpha (α) and beta (β). In the figure, the angles alpha (α) and beta (β) are equal; however, this is not necessary. For example, for a north-south orientation, these angles are unequal, and the PV panels on the north side do not contain photovoltaic cells. The low rolling resistance between the wheels (6) and the guide rail (9) or foundation prevents the deployment movement from slowing down. If desired, the deployment movement can be slowed down by using sliders or rollers with higher rolling resistance instead of wheels. Since the mechanism is fixed on one side, only linear movement (a) is possible. This is possible with multiple connected pairs (I, II, ......n) of solar panels (see Figure 3). Figure 3 shows such a system deployed in a spatial view for PV or solar panels (1) with four mechanically connected pairs (I to IV) which are connected by tension and compression elements (3, 4). The lattice structure created in this way forms a large self-supporting span in the longitudinal direction (x), with resistance against positive and negative loads (caused, for example, by wind uplift) from its own weight, wind, and snow; the principle of a bridge. In Figure 4, the maximum span L in the longitudinal direction (x) depends on the orientation of the solar panels (1) and the angle beta (β), which determines the height of the lattice structure. Increasing the height (h) increases the strength or bending resistance of the lattice structure. The PV panel generally consists of a panel with photovoltaic solar cells surrounded by a frame (1). A single panel, as shown, can consist of one or more solar panels in a horizontal or vertical orientation with varying final lengths (L1, L2) and widths (B1, B2). Sometimes, the protective frame or side edge (2) is integrated directly into the PV panel. Figure 5 shows a system that is pre-assembled and, in its folded state, is placed on the roof (edge) using a lifting, hoisting, or transport machine, after which it is unfolded in a linear motion. During unfolding, the wheels (6) support the system, which moves directly on the foundation or along a rail (5). A large number of panels can be connected, but for the purposes of this explanation, only four connected pairs are shown. Figure 6 shows a detail of the system, where the top-side solar panel (1) frames (2) are hinged (5) and horizontally connected to the top-side tension-compression element (3). Figure 7 shows a detail of the underside with the hinged connection point (5) of the frame (2) and the solar panel (1) equipped with a wheel (6) that moves along the lower beam or rail (9) or directly on the foundation. During deployment, the beta angle will decrease with respect to the horizontal (the roof surface). Figure 8 shows a system fully connected in both directions (x, y). By connecting the transverse partitions (7) with connecting elements (8), the system is also rigidly connected to the adjacent PV system. The final shape of the connecting element (8) depends on the distance between the two adjacent PV systems and is larger if space is required between the connected PV panels (14), for example, to create a pedestrian walkway. The figure shows that, due to the structurally load-bearing nature of the invention, a PV system can also be installed on a foundation with only a limited number of irregularly distributed load-bearing points (13) (as is the case with a "weak" roof). Figure 9 shows a spatial view from below the structure to clearly illustrate the different functions of the cross-brace (7). The cross-brace is necessary to create a rigid connection perpendicular to the deployment direction (y), but it also supports and guides the compression member of the lower stresses (4) if it is hinged at the center (point d). The transverse division in this configuration can serve as a buckling length shortener, as well as a fastening and locking element for the deployed system. If two adjacent PV systems are rigidly connected, the connecting element (8) can be connected to points c and d. It should be noted that the invention is not limited to the embodiments discussed above. It is also possible to use flexible strips instead of hinges between the panels or frames. It may also be possible to establish a clamping connection at the hinges when the panels or frames reach their final relative angle. These and other variations will be evident to the expert person and should be considered within the scope of the invention, as indicated in the attached claims. List with reference numbers 1. PV - or solar panels: 2. Side edges of the solar panel: 3. upper side of the tension or compression element: 4. lower side of the tension or compression element: 5. articulation point: 6. wheel 7. cross-section 8. Connecting element 9. Rail: 10. Fulcrum 11. Fixing point: 12. Foundations or roof 13. Load support point on the support structure 14. Space List of symbols used x longitudinal direction of the PV system and transverse direction perpendicular to the PV system Solar panel angle to foundation / roof ß Solar panel angle - foundation / roof h Height of the lattice structure the displacement of the mechanism in the horizontal direction b. Vertical displacement of the mechanism c point of articulation d point of articulation I, II, III, IV numbering of some solar panels of the system L distance of the deployed system L1 PV Panel Length B1 PV Panel Width L2 PV Panel Length B2 PV Panel Width

Claims

1. A photovoltaic (PV) system, suitable for installation on a weak foundation (12) having load-bearing points for supporting the PV system, for example a roof (12), comprising several panels with solar cells and / or frames (1) suitable for fixing solar panels (1), wherein the panels and / or frames (1) are structurally load-bearing components of the system, wherein the system comprises a folded and unfolded configuration, and wherein the panels and / or frames (1), both on the upper side (3) and also on the lower side (4), are connected using tension or compression elements (3, 4), characterized in that in an unfolded configuration a space lattice structure is created with a large self-supporting span in the longitudinal direction (x) parallel to the load-bearing points, where a bridge is formed between the load-bearing points (10, 13) of the foundation. 2.PV system according to claim 1, wherein the panels and / or frames (1) are connected to each other by means of hinges.

3. PV system according to claim 2, wherein the panels and / or frames (1) include two opposite lateral edges (2), wherein the system comprises at least two end panels and / or frames (1) and, optionally, consists of several intermediate panels and / or frames (1), wherein the hinged or non-hinged intermediate panels and / or frames (1) are connected to a previous panel (1) and to a second hinged or non-hinged edge (2) connected to a subsequent panel or frame (1), and wherein the distal panels and / or frames (1) are connected only by either the first or the second edge (2) to a previous or subsequent panel or frame (1).

4. PV system according to claim 3, wherein in the deployed configuration the panels and / or frames (1) form an angle with the adjacent solar panels (1).

5. A PV system according to any one of the preceding claims, wherein the panels and / or frames (1) are alternatively provided with sliders, rollers, or wheels (6) at a first lateral edge (2) or a second lateral edge (2).

6. A PV system according to claim 5, wherein the panels and / or frames (1) are alternatively provided with tension or compression elements (3, 4) at a first lateral edge (2) or a second lateral edge (2) that create a connection from the first lateral edge (2) of a first panel (1) to the second lateral edge (2) of an adjacent following and / or adjacent preceding solar panel (1).

7. A PV system according to claim 5 or 6, wherein the system is provided with extension rails (5) or guides (9) on or above which the sliders, wheels (6), or rollers can move. 8.PV system according to one of the preceding claims, wherein the panels and / or frames (1) also contain wind protections or roof plates.

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