DE102022127185A1 - Support structure for non-load-bearing roofs - Google Patents

Abstract

The invention relates to a solar energy structure (1000) in which a support structure (110) for PV modules (PVM) is arranged on a building (G) with, for example, a flat roof. According to a preferred embodiment, the support structure contains support beams (112) which extend in a self-supporting manner between supports (120) in the edge region of the building (G).

Description

The invention relates to a solar energy structure, a support structure for non-load-bearing roofs, in particular for supporting photovoltaic modules for such a solar energy structure, as well as supports for such a support structure.

For reasons of sustainable energy production, it is desirable to use as many roof surfaces of buildings as possible for the installation of PV modules (where "PV" is the usual abbreviation for "photovoltaics"). Flat roofs are particularly suitable for this purpose, such as those found on factory halls, warehouses, exhibition halls and the like, with the total size of all German storage, logistics and production areas over 1000 square meters being 0.6 billion square meters (source: IndustrialPort, 2012). The problem here, however, is that these roofs have only a relatively low load-bearing capacity in internal areas due to their size. Furthermore, damage to the roof covering must be avoided in order to avoid leaks or heat loss.

Against this background, the object of the present invention was to provide means for the expanded use of photovoltaics.

This object is achieved by a solar energy structure according to claim 1, by a support structure according to claim 3, and by a support according to claim 10. Advantageous embodiments are contained in the subclaims.

• - Ein (herkömmliches) Gebäude mit einem Dach, wobei das Dach in einer vorgegebenen Bezugsrichtung eine Erstreckungsweite von mindestens 5 Metern aufweist. Die Breite des Daches in einer Richtung quer zur Bezugsrichtung ist vorliegend nicht weiter spezifiziert, sie beträgt jedoch typischerweise mindestens ebenso viel wie die Erstreckungsweite in der Bezugsrichtung. Bei dem Dach kann es sich insbesondere um ein Flachdach oder ein Dach geringer Neigung handeln. Das Gebäude soll weiterhin mindestens zwei Vertikalträger zur Aufnahme vertikaler Lasten aufweisen, beispielsweise in Form von tragenden Ständern oder Säulen. Derartige Vertikalträger befinden sich typischerweise im Randbereich (Wände) des Gebäudes, sie können jedoch auch in inneren Bereichen vorgesehen sein.
• - Eine PV-Anlage mit einer Trägerkonstruktion, wobei auf der Trägerkonstruktion mindestens ein PV-Modul befestigt ist und wobei sich die Trägerkonstruktion über (mindestens) die vorstehend genannte Erstreckungsweite erstreckt. Unter einem „PV-Modul“ wird in diesem Zusammenhang wie üblich die kleinste selbstständige bauliche Einheit verstanden, welche zur Umwandlung von eingestrahltem (Sonnen-) Licht in elektrische Energie und zu deren Abgabe an einer definierten Schnittstelle (z.B. eine Kupplung) ausgelegt ist. Typischerweise haben PV-Module eine Fläche von ca. 0,5 bis 4 Quadratmetern.

According to its main aspect, the invention relates to a solar energy structure comprising the following components:

• - A (conventional) building with a roof, the roof having an extension of at least 5 meters in a given reference direction. The width of the roof in a direction transverse to the reference direction is not further specified here, but is typically at least as much as the extension in the reference direction. The roof can in particular be a flat roof or a roof with a slight slope. The building should also have at least two vertical supports to support vertical loads, for example in the form of load-bearing posts or columns. Such vertical supports are typically located in the edge area (walls) of the building, but they can also be provided in interior areas.
• - A PV system with a support structure, with at least one PV module attached to the support structure and with the support structure extending over (at least) the above-mentioned width. In this context, a "PV module" is understood as the smallest independent structural unit designed to convert incident (sun) light into electrical energy and to release it at a defined interface (e.g. a coupling). PV modules typically have an area of approx. 0.5 to 4 square meters.

The solar energy structure is further characterized in that the support structure is supported on the building in the reference direction essentially only in the area of vertical supports of the building.

The "essential" support means that smaller proportions of typically less than around 25%, preferably less than 15%, of the weight carried by the support structure can also be transferred to the building at points between the vertical support points. In other words, as a rule at least 75% of the forces absorbed by the support structure are transferred to the building in the area of vertical supports or directly to the vertical supports, columns and/or walls. Between the support points, the support structure is therefore self-supporting or at least predominantly self-supporting.

The "area of a vertical support" includes in particular the area of the vertical support as seen in a vertical projection. In addition, this area also includes a zone with a maximum width of approximately 5 meters, preferably approximately 3 meters (or with a maximum width of approximately 20% of the extension) around this projection area.

The solar energy structure described has the advantage that, for example, a PV system can be installed on the flat roof of a building that uses the entire area without the latter putting a strain on or overloading areas inside the flat roof. This is achieved by using the support structure to transfer the weight forces essentially to the edge areas of the building, where they can be easily absorbed by suitably stable vertical supports (walls, columns). This increases the value of the building through the possibility, which is important today, of generating a lot of energy on a roof surface or renting out the roof surface.

One of the critical points when installing a PV system on a (flat) roof is that the waterproofing and thermal insulation of the roof covering must remain as intact as possible. With conventional elevated systems that are weighted down with ballast stones, a lot of damage occurs that becomes apparent immediately or later (see report from the Aachen Institute for Building Damage Research and Applied Building Physics). In contrast, with a further development of the solar energy structure, the roof covering can be protected by supporting the support structure on at least one support that runs through the roof covering and extends vertically upwards over the roof surface. In the lower area, the support is preferably arranged directly or indirectly on vertical beams or cross beams of the building, so that the loads are introduced directly into the vertical beams and do not place static loads on the roof surface. Because the support extends upwards above the roof surface, it can be tightly integrated into the roof covering, for example using sealing strips that are bent upwards. Softer parts of the roof are not stressed by the support, as the latter can be placed directly on the load-bearing components. Furthermore, the support can preferably be made of a heat-insulating material so that it does not create a cold bridge. Typically, the support structure is supported on such supports at all load-bearing points. Furthermore, the support of the support structure on a support is preferably carried out in such a way that, for example, by means of a base plate with elongated holes, at least a certain degree of mobility remains perpendicular to the support direction in order to be able to compensate for movements of the support structure in the longitudinal direction relative to the building (e.g. due to thermal expansion).

According to a first secondary aspect, the invention further relates to a support structure for non-load-bearing roofs, which is particularly suitable for a solar energy structure of the type described above. The support structure is characterized in that it contains at least one support beam which extends over the extent defined above. As the name "beam" is intended to indicate, the geometric shape of the support beam is essentially straight with an elongated extension, wherein the length of the support beam should be significantly (e.g. at least five times) greater than its dimension in directions transverse to the length.

Within the support structure, the support beam is a load-bearing element that can absorb forces from the surface and concentrate them along a line or at the ends of the support beam. The support beam can in particular be designed so that it extends freely between two supports located at its ends or close to its ends when it supports its own weight and the weight of PV modules arranged on the support structure as well as any other loads (snow, wind, etc.).

The support beam can be designed in various ways, although it does not have to be a solid body. In particular, the support beam can be designed as a truss structure, i.e. as a framework whose bars are only subjected to longitudinal forces and whose ends are connected to one another at nodes. This makes it possible to have a stable and very lightweight structure.

According to a preferred embodiment, the support beam is constructed modularly from support beam modules arranged one behind the other. The individual support beam modules can have different, but in particular also identical, designs. By connecting several modules in series, support beams of virtually any extension width can be produced. Furthermore, the modular design facilitates both the production and the transport of the support beams or the support structure.

The support beam modules mentioned above can optionally be firmly connected to one another, for example by screw connections or welding. However, they can also be loosely joined together, in which case appropriate force must be applied to ensure that the modules do not separate again on their own.

According to another embodiment, the support beam contains a clamping device with the aid of which a compressive force running in the direction of extension of the support beam can be generated between the ends of the support beam. The clamping device can be a wire rope or a metal rod, for example. The clamping device can be used to stabilize the support beam, in particular if the beam is formed by the clamping device into a (slightly) convex shape with a curvature against gravity. Weight forces to be absorbed are then diverted into horizontal forces at the connection points of the modules, which can, however, be easily absorbed by the clamping device.

The compressive force generated by the clamping device in the longitudinal direction of the support beam is typically higher than the weight of the support beam. In particular, it can be approximately 2 to 10 times the weight.

According to another development, the support beam is compression-stable. This means that it can withstand forces that compress it in the direction of its extension. The compression stability can in particular be at least so high that the support beam can withstand compression forces that are 2 times, preferably 5 times, 10 times, 50 times or even 100 times its own weight. A support beam that is compression-stable in this way can be stabilized against the absorption of vertically acting weight forces by correspondingly high compressive forces. The compressive forces mentioned can be applied via a clamping device as described above. However, they can also be generated without such a clamping device, for example by parts of the building or an adjacent support structure that abuts in the longitudinal direction.

According to a further embodiment, the support structure contains at least one traction means, such as a cable, for transmitting upwardly directed tensile forces. In this way, weight forces can be transmitted from locations remote from the support points of the support structure to the support points.

In a further development of the embodiment described above, the support structure contains at least one pylon element (which protrudes upwards when installed) to which the traction device is attached. Similar to suspension bridges or cable-stayed bridges, weight forces can thus be absorbed by the pylon element. The pylon element is preferably arranged in the area of a support of the support structure.

A further secondary aspect of the invention relates to a support for supporting a carrier structure according to one of the embodiments described above on a building. The support is characterized in that it contains load-bearing components made of a rigid foam. In particular, it can consist entirely of a rigid foam.

The base material of the rigid foam is typically a plastic such as polyethylene (PE), polypropylene (PP), polystyrene (PS), polyurethane (PU) or the like. By forming it as a rigid foam, a high level of stability is achieved, which can absorb the weight forces that occur. Furthermore, the rigid foam has good thermal insulation properties due to the gas it contains, so that it does not lead to cold bridges when integrated into a roof covering. The density of the rigid foam is preferably at least approx. 200 kg per cubic meter.

Preferably, a metal base plate containing corresponding threaded holes is foamed into a rigid foam block of the type described. If a first rigid foam block is screwed onto the hall support via these threaded holes, further rigid foam blocks can then be placed on top of each other and screwed together, just like with LEGOO bricks. If there is an obstacle on the roof, for example a strip of skylights or a dormer window, the half-timbered support beams can be raised accordingly using the building blocks.

• 1 einen Querschnitt durch den Dachbereich eines erfindungsgemäßen Solarenergie-Bauwerkes;
• 2 einen Querschnitt durch den Dachbereich eines weiteren Solarenergie-Bauwerkes, welches zusätzlich Zugmittel und Pylonelemente aufweist;
• 3 eine vergrößerte Detailansicht einer in die Dachhaut integrierten Auflage;
• 4 ein Solarenergie-Bauwerk mit Satteldach und Lichtband;
• 5 ein Solarenergie-Bauwerk mit Dachgauben;
• 6 ein Solarenergie-Bauwerk mit Dachversatz;
• 7 ein Solarenergie-Bauwerk mit Tonnendach.

The invention is explained in more detail below using an exemplary embodiment with the aid of the attached figures.

• 1 a cross-section through the roof area of a solar energy structure according to the invention;
• 2 a cross-section through the roof area of another solar energy structure, which additionally has traction devices and pylon elements;
• 3 an enlarged detailed view of a support integrated into the roof skin;
• 4 a solar energy building with a gable roof and skylight;
• 5 a solar energy structure with dormer windows;
• 6 a solar energy structure with offset roof;
• 7 a solar energy structure with a barrel roof.

The need for renewable energy will rise sharply in the future due to the politically desired and environmentally necessary move away from fossil fuels. However, solar systems will only be built on a significant scale if they are economically viable.

Since many buildings have unused roof areas, these previously untapped resources can be used to install photovoltaic systems. However, existing roofs, including the supporting structure, insulation and roof sealing, are not designed for the installation of solar systems. They lack proof of positional stability, stability due to the coefficient of friction, a guarantee for roof sealing when a photovoltaic system is subsequently installed, etc.

PV systems on flat roofs do not require approval in many federal states. Nevertheless, there are critical aspects that primarily affect the statics and roof sealing. With photovoltaic systems, there is not only the building statics, but also the system statics (stable position) of the solar system. Basically, every building must be stable as a whole and in its parts (§12 Model Building Code MBO). This means that a static proof must be provided. The static proof must be provided by the manufacturer of the solar system. This must provide proof of the load-bearing capacity of the collector or module, the mounting system up to the fastening in or on the building, taking into account the existing subsurface (wood, wood materials, steel construction, trapezoidal steel sheeting, reinforced concrete, folded roof) in accordance with the applicable regulations. According to experts, however, a complete static proof is not possible.

Against this background, the following suggestions for supporting structures, which are explained in more detail using exemplary embodiments, are made with which PV systems can be installed on (existing) buildings.

• - Zum einen dem herkömmlichen Gebäude G mit einem Flachdach, wie es beispielsweise bei Fabrikhallen, Schulen, Turnhallen, Tankstellen, Parkplatzüberdachungen, Supermärkten, Schützenhallen, Stadien und dergleichen zu finden ist. Ein derartiges Gebäude enthält in regelmäßigen Abständen Vertikalträger VT, beispielsweise aus Stahl, die in gegenüberliegenden Wänden im Abstand der Erstreckungsweite w des Gebäudes (in x-Richtung) aufgestellt sind und miteinander durch horizontale Träger HT (Binder) verbunden sind. Auf den horizontalen Trägern sind beispielsweise Trapezbleche TB, welche die Dachfläche bilden, sowie eine Wärmedämmung WD angeordnet. An der Dachoberfläche DO ist das Gebäude durch hier nicht näher dargestellte Dichtbahnen wasserdicht verschlossen.
• - Als zweite Komponente enthält das Bauwerk eine PV-Anlage 100. Diese besteht aus einer Trägerkonstruktion 110 mit an der Oberseite befestigten PV-Modulen PVM. Die Trägerkonstruktion 110 wiederum besteht aus den in 1 erkennbaren Trägerbalken 112, welche sich jeweils linear in der Bezugsrichtung x erstrecken, sowie auf den Trägerbalken angeordneten und senkrecht zur Bezugsrichtung (d.h. in y-Richtung) verlaufenden Querstäben 111.

In 1 the roof area of a solar energy structure 1000 is shown in a section along a reference direction (x-axis of the coordinate system shown). The structure essentially consists of two components:

• - Firstly, the conventional building G with a flat roof, such as can be found in factories, schools, gyms, petrol stations, car park roofs, supermarkets, shooting ranges, stadiums and the like. Such a building contains vertical beams VT at regular intervals, for example made of steel, which are set up in opposite walls at a distance equal to the building's extension w (in the x direction) and are connected to one another by horizontal beams HT (binders). Trapezoidal sheets TB, which form the roof surface, and thermal insulation WD are arranged on the horizontal beams. On the roof surface DO, the building is sealed watertight by sealing sheets (not shown here).
• - As a second component, the structure contains a PV system 100. This consists of a support structure 110 with PV modules PVM attached to the top. The support structure 110 in turn consists of the 1 visible support beams 112, each of which extends linearly in the reference direction x, as well as cross bars 111 arranged on the support beams and running perpendicular to the reference direction (ie in the y-direction).

The support structure 110 thus contains support beams 112, which represent a stable connection over the extension width w. For this purpose, the support beams 112 can be constructed, in particular as shown, from a two- or three-dimensional truss structure with struts 116, 117, so that a high level of stability is achieved while at the same time being low in weight.

Such a truss girder 112 (lattice girder, frame element) is a construction made of several bars that are connected to each other at both ends. The truss girders can preferably be manufactured in a lightweight construction, for example with a tube laser in lengths of 5/10/15/20 m and 25 m or in special lengths and sizes.

At their ends, the support beams 112 are supported by two supports 120 on the load-bearing elements HT, VT of the building G. Between the supports 120, however, the support beams 112 are self-supporting. This can be made possible by a suitably rigid construction of the support beams.

Since the truss 112 with its support plate lies directly on the position of the hall supports VT, the resulting loads are introduced directly into the vertical supports VT and do not load the roof.

The 112 trusses can optionally extend beyond a hall roof in order to achieve the best possible PV module size. Furthermore, they can extend over strip lights, skylights, roof windows, roof hatches, etc. so that the roof area can be used optimally with the distribution of the PV module size.

In particular, clamping devices (not shown) that run from one end of a support beam 112 (in the x direction) to the other end and exert a compression force on the support beam can also contribute to stabilization. The support beam can take on a slightly upwardly curved shape, through which (similar to a toggle lever) vertical forces are diverted into horizontal forces, whereby the horizontal forces can be absorbed by the clamping device. In this context, the support beam 112 can in particular consist of individual, similar support beam modules 115, which can be firmly connected (e.g. screwed, welded) or loosely (e.g. inserted into one another) and typically each carry a single PV module PVM.

In 2 is in a view like in 1 Another solar energy building in 2000 is shown, in which, similar to the one described above, a solar system with a Support structure 210 is arranged from support beam modules 215, whereby in the drawing analogous components as in 1 have been given reference numbers increased by "100". The support beam modules 215 again have a lattice construction, whereby the details of the lattice shown can vary.

In contrast to the previously described embodiment, the support structure 210 has pylon elements PY at the ends of the support beams, which extend essentially vertically upwards. The base of the pylon elements PY rests on the supports 220 above the vertical beams VT of the building. Furthermore, the pylon elements are supported by pressure-resistant angle struts WS in the direction of the interior of the support structure 210 (e.g. supported to the right in the case of the pylon element PY at the left end of the support structure 210). This makes it possible to attach tension cables to the upper ends of the pylon elements PY, via which tensile forces directed diagonally upwards can be transmitted to inner parts of the support structure. In the drawing, the left half shows the case of a single tension cable ZS, and the right half shows the case of three fan-shaped tension cables ZS1, ZS2, ZS3.

To reduce the shear load on the PV systems, a simple roof heating system can optionally be installed on the PV modules.

The area of a circulation of 120 is in 3 shown in more detail. It can be seen that the support 120, which in the example shown is essentially cuboid-shaped, passes through the trapezoidal sheets TB and the high-performance insulation WD of the roof covering and is connected directly to the metal supports VT, HT of the building G with the interposition of a metal plate 122. The support 120 protrudes upwards beyond the top of the roof DO so that sealing sheets running on it can be glued upwards onto the support 120.

The support 120 preferably consists of a rigid foam that combines sufficient stability with thermal insulation properties. The metal plate 122 can be foamed into the rigid foam block 121 via anchors and can have threaded holes for screwing to the building.

Optionally, a support 120, 220 can also contain several injected metal plates that are placed on the hall supports and screwed in place. Supports can be manufactured in different lengths, widths and heights and can be placed on top of one another and connected (screwed) together like Lego bricks with studs.

To install the PV systems described, a rectangular hole is cut into the roof (roof covering, insulation, trapezoidal sheeting, wooden formwork) in the edge area of a roof directly above the load-bearing supports VT (made of steel, reinforced concrete or wood) of the hall construction so that a drilling template can be placed on the hall support. Then a corresponding hole pattern is drilled in the top of the hall support, a thermal hard foam block is placed on top and screwed in place. This plastic block can be installed and varied in height depending on the structural situation. Optionally, several hard foam blocks can be placed on top of each other and screwed together like Lego bricks.

The rigid foam blocks typically protrude approximately 100 mm to 300 mm above the flat roof insulation. The existing roof cutout with the inserted plastic block can therefore easily be sealed and permanently bonded by the roofer with an EPDM film, plastic sheet or bitumen roof membrane.

The prefabricated system truss beam is then placed with its ends (“left” and “right”) on the rigid foam blocks and screwed in place. The support plates of the truss beam preferably have elongated holes so that no longitudinal stresses can arise when different materials expand.

The next step is to place and fasten a substructure made of metal profiles or components 111, 211 across the lattice beams on which the PV modules PVM rest in a row. This substructure can optionally be equipped with a mechanism so that the PV modules are always optimally aligned with the sun. In addition to increasing the yield with such a tracking system, the adjustability of the PV modules can also be used to remove snow loads, for example by rotating the modules into a vertical position.

• - die Rückbestromung der PV-Module zur Schneeschmelzung;
• - Anordnung je einer linearen Linienführung links und rechts der PV-Module, zwischen denen ein Seil geführt ist, das zur Entfernung von Schnee herauf und herunter gefahren werden kann;
• - Spritzen von Enteisungsflüssigkeit auf das PV-Modul mittels Sprühdüsen;
• - Anordnung von Scheibenwischern an den PV-Modulen zur Entfernung von Schnee.

In order to remove snow loads from the PV modules in winter, the following approaches can be pursued additionally or alternatively:

• - the re-powering of the PV modules for snow melting;
• - Arrangement of a linear line to the left and right of the PV modules, between which a rope is guided, which is used to remove can be driven up and down snow;
• - Spraying de-icing fluid onto the PV module using spray nozzles;
• - Arrangement of windscreen wipers on the PV modules to remove snow.

The 4 to 7 illustrate different applications of the described support structure for different conditions and shapes of roofs.

This shows 4 a solar energy structure 3000 with a gable roof and a light strip LB, the latter being bridged by a correspondingly high arrangement of the support structure. The support structure can be brought to the desired height in particular by stacking several supports on top of each other like building blocks. The use in the figure shows that support blocks can interlock with each other using studs in a similar way to LEGOO bricks.

5 shows a solar energy structure 4000, in which dormer windows DG are bridged in a similar way.

6 shows a solar energy structure 5000, in which a roof offset is bridged or compensated by (optionally different height) supports on different sides of the support structure.

7 shows a solar energy structure 6000 with a barrel roof. The support structure or support beams here are curved to match the shape of the roof. The support structure described can therefore easily be used on various roof shapes, for example a flat roof, barrel roof, pent roof, flat gable roof or butterfly roof. Furthermore, a steel structure can be retrofitted for non-load-bearing roof areas, e.g. on existing supports or beams using screw-on brackets and roof supports.

Claims (10)

Solar energy structure (1000-6000), comprising - a building (G) with a roof which has an extension (w) of at least 5 m in a reference direction (x), wherein the building (G) contains at least two vertical supports (VT) for absorbing vertical loads; - a PV system (100) with a support structure (110, 210) on which at least one PV module (PVM) is fastened and which extends over the extension (w), wherein the support structure (110, 210) is supported on the building (G) in the reference direction (x) essentially only in the region of vertical supports (VT) of the building (G). Solar energy building (1000-6000) after Claim 1 , characterized in that the support structure (110, 210) is supported on at least one support (120, 220) which runs through the roof skin (TB, WD) of the building (G) and extends upwards over the roof surface (DO). Support structure (110, 210) for a solar energy building (1000-6000) according to Claim 1 or 2 , characterized in that it contains at least one support beam (112) which extends over the extension width (w). Support structure (110, 210) according to Claim 3 , characterized in that the support beam (112) has a truss construction. Support structure (110, 210) according to Claim 3 or 4 , characterized in that the support beam (112) is constructed from support beam modules (115, 215) arranged one behind the other. Support structure (110, 210) according to at least one of the Claims 3 until 5 , characterized in that the support beam (112) contains a clamping means, with the aid of which a compressive force extending in the extension direction (x) of the support beam can be generated between the ends of the support beam. Support structure (110, 210) according to at least one of the Claims 3 until 6 , characterized in that the support beam (112) is compression-stable in its extension direction (x). Support structure (210) according to at least one of the Claims 3 until 6 , characterized in that it has at least one traction means (ZS, ZS1, ZS2, ZS3) for transmitting upwardly directed tensile forces. Support structure (210) according to Claim 9 , characterized in that it contains at least one protruding pylon element (PY) to which the traction means (ZS, ZS1, ZS2, ZS3) is attached. Support (120, 220) for supporting a support structure (110, 210) according to at least one of the Claims 3 until 9 on a building (G), characterized in that the support (120, 220) contains load-bearing components made of rigid foam.

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