Modular substructure of concrete for solar panels

Abstract

The invention describes a modular substructure (1) of concrete for solar panels (2, 2') for placement on a flat roof (3), said substructure comprising a plurality of cross-beams (4, 4'), wherein the cross-beams (4, 4') each have a mounting surface (10) for fastening the solar panels (2. 2'), and wherein the mounting surface (10) has an angle of inclination with respect to the horizontal which corresponds to the angle of inclination of the solar panels (2, 2'). The substructure (1) has a longitudinally oriented central beam (5) with a bottom side (12) and a top side (13), wherein the bottom side (12) of the central beam (5) is designed as a flat surface (19) for placement on a flat roof (3), wherein the one central beam (5) connects the plurality of cross-beams (4) with one another and has, on the top side (13), a plurality of grooves (6, 6') and / or support surfaces (18) for receiving the cross-beams (4, 4') such that the cross-beams (4, 4') are inserted interlockingly in the grooves (6, 6') and / or are mounted lying on the support surfaces (18) and are fastened to the central beam (5). The central beam (5) and the cross-beams (4, 4') are of lightweight concrete.

Description

[0001] Modular concrete substructure for solar panels

[0002] Technical area

[0003] The invention relates to a concrete substructure for solar panels for installation on flat roofs.

[0004] State of the art

[0005] Concrete substructures for solar panels are known. For example, WO2021 129067A2 describes a system and method for attaching one or more photovoltaic modules to at least one modular rail. The modular rail is made of solid concrete.

[0006] US2013276304A1 describes a solar panel mounting system comprising a plurality of solar panel support structures that can be formed from solid concrete in adjacent rows with mounting surfaces inclined towards the equator.

[0007] DE3346077A1 discloses a substructure for a solar panel having semiconductor photovoltaic elements, which rests on a support of the substructure which is inclined to the horizontal and is a wedge-shaped concrete block.

[0008] WO201 3108541 A1 describes a trapezoidal base made of concrete as a substructure for solar panels, which are connected to each other via connecting rods.

[0009] DE102008052600A1 describes a solar system with a support structure and a photovoltaic module arranged on the support structure for generating electrical energy from sunlight. The support structure is designed as an L-shaped concrete component comprising a back part and a base part connected to the back part. The back part comprises an inner surface facing the base part and an outer surface opposite the inner surface, on which the photovoltaic module is arranged. The support structure is made of solid concrete with reinforcing steel.

[0010] The disadvantage of conventional substructures is that they are heavy and require laborious measurement and securing before installation or placement on the roof because, due to their weight, they cannot be moved once installed. Furthermore, most systems require the removal of the existing roof coverings prior to installation. Furthermore, scaffolding is required to install these substructures. With conventional substructures, one substructure is usually used per solar panel, or the individual base components rest on the roof, each with a corresponding point load on the roof. These solutions are therefore neither economical nor ecologically efficient, and their manufacture and installation are time-consuming.

[0011] Object of the invention

[0012] The present invention is based on the object of creating a substructure for solar panels which is light and easy to transport, which is simple, cost-effective and CO 2 -low, which can be assembled quickly and easily, on which the solar panels can be easily mounted without prior measuring, and in which the load of the structure can be distributed over a larger area.

[0013] Description of the invention

[0014] This object is achieved by a modular concrete substructure for solar panels for installation on a flat roof, which comprises a plurality of cross beams, wherein the cross beams each have a mounting surface for fastening the solar panels, and wherein the mounting surface has an angle of inclination relative to the horizontal or the flat roof surface which corresponds to the angle of inclination of the solar panels. The substructure additionally has a longitudinal central beam with a bottom side and a top side, wherein the bottom side of the central beam is designed as a flat surface for resting on a flat roof, and wherein one central beam connects the plurality of cross beams to one another and has a plurality of grooves and / or support surfaces on the top side for receiving the cross beams, such that the cross beams are positively inserted in the grooves and / or are mounted resting on the support surfaces and are fastened to the central beam.The central beam and the cross beams are made of lightweight concrete.

[0015] The advantage of such a modular substructure is that the individual modules, i.e. the cross beams and the central beam, can be manufactured separately, transported and then fully assembled on the roof. Modules are prefabricated components that are industrially produced and then assembled on the flat roof to form a finished structure, the so-called modular substructure. The modules include the cross beams and the central beam, which are required to manufacture the modular substructure. The individual modules are easy to manufacture and transport and can, for example, be placed on a flat roof with a crane and then moved and assembled by hand. Preferably, the central beam is placed on the flat roof with a crane and positioned, and the cross beams are assembled onto the central beam by hand.Upon request, the substructure can also be delivered fully assembled and positioned at the desired location on the flat roof. A flat roof is defined as one with a roof pitch of less than 10°, preferably less than 5°, and even more preferably with a roof pitch of 0°. Normal roof pitches on flat roofs are taken into account when calculating the desired inclination of the solar panels.

[0016] "Longitudinally" means that the elongated central beam can accommodate several crossbeams in the longitudinal direction of the central beam, on which several solar panels can be mounted side by side. The crossbeams are mounted and arranged transversely to the longitudinal direction of the central beam. The longitudinal central beam has the length of the modular substructure in the longitudinal direction of the substructure. Preferably, the plurality of crossbeams are each arranged at a right angle to the longitudinal central beam.

[0017] Throughout the present invention, beam is understood to mean an elongated shaped part which has, for example, a square, rectangular, trapezoidal, T-shaped or L-shaped cross-section.

[0018] The longitudinal central beam is a single continuous beam and connects all of the multiple crossbeams of a modular substructure. The longitudinal central beam preferably has a top side and a bottom side, which are arranged essentially parallel to each other. The top side of the central beam is understood to be the side of the central beam that faces away from the flat roof when installed on a flat roof, while the bottom side of the central beam is understood to be the side of the central beam that rests on the flat roof when installed on a flat roof and forms a contact surface and a supporting surface with the flat roof.The upper side either has several grooves for receiving the crossbeams, so that the crossbeams are inserted into the grooves with a form-fitting fit, or the surface has support surfaces for receiving the crossbeams, so that the crossbeams rest on the support surfaces. Particularly preferred is the embodiment in which the longitudinal central beam has support surfaces for receiving the crossbeams, so that the crossbeams rest on the support surfaces and are attached to the central beam.

[0019] An essential aspect of the present invention is that the underside of the longitudinally elongated central beam is designed as a flat surface, preferably as a continuously flat surface, such that the flat surface forms a supporting surface which, when the substructure is erected on a flat roof, can rest completely on the flat roof. The supporting surface is understood to be the flat surface on the underside of the longitudinally oriented central beam which fully bears the weight of the modular substructure and which can rest completely on a flat roof. The supporting surface can also be referred to as a support surface. As a result, the weight of the substructure is distributed over a large area and places less localized load on the flat roof than with conventional substructures in which the weight is transferred to the flat roof via a point or an edge.

[0020] In one embodiment, the central beam has a protective layer on its underside for support on a flat roof. The protective layer is preferably arranged continuously on the underside of the central beam and thus forms the supporting surface and support surface on a flat roof. The protective layer is preferably made of plastic, preferably foamed plastic. A protective layer made of extruded polystyrene is particularly preferred. The protective layer provides protection against damage to the flat roof surface, in particular to the roof membranes that are susceptible to damage. This makes the substructure according to the invention suitable for all known flat roof coverings. The central beams provided with a protective layer are placed on gravel roofs, for example. For green roofs or roofs where the roof covering is protected by substrate or soil, a protective layer on the underside of the central beam can be omitted.

[0021] In one embodiment, the top side of the central beam has three to ten, more preferably four to eight, grooves and / or support surfaces for receiving the cross beams and corresponds to the number of cross beams that are mounted on the central beam. The plurality of grooves are arranged as an elongated recess transverse to the longitudinal direction of the central beam and preferably have a rectangular cross-section into which the cross beams can be inserted in a form-fitting manner and which have a bottom surface that corresponds to the support surface for supporting the cross beams. In a further embodiment, the bottom surface of the groove and / or the support surface is chamfered and has an angle of inclination that corresponds to the angle of inclination of the mounting surface of the cross beams. In a groove with a chamfered bottom surface, also referred to as a beveled groove, the rectangular cross-sectional area decreases in the longitudinal direction of the groove towards the top side of the central beam.The beveled groove is the preferred embodiment for a crossbeam with a rectangular or square cross-section.

[0022] In a further embodiment, the bottom surface of the groove and / or the support surface for receiving the crossbeams is horizontal, also referred to as a horizontal groove, and corresponds to the inclination of the underside or the supporting surface of the central beam. This embodiment is preferred for a crossbeam with a gable-shaped cross-section.

[0023] The design, in which the central beam has several grooves and the crossbeams are inserted into the elongated recesses with a form-fitting fit, provides additional stability for the attachment of the crossbeams to the central beam. Furthermore, installation is particularly easy if the angle of inclination of the base surface of the groove matches the angle of inclination of the solar panels to be mounted. The angle of inclination of the solar panels does not need to be adjusted during installation, and the solar panels can be easily mounted on the crossbeam without any measurements.

[0024] In a further embodiment, the longitudinal central beam has a cross-section of a rectangular trapezoid, in which the side surfaces are arranged parallel to each other and at right angles to the underside, and wherein the upper side is bevelled and has an angle of inclination relative to the underside which corresponds to the angle of inclination of the mounting surface of the cross beams or the solar panels to be mounted.

[0025] In a preferred embodiment, the central beam does not have recessed grooves on its surface, but rather several support surfaces, which serve as markings and assembly aids for attaching the crossbeams. These support surfaces may also include a mounting rail for assembly. During assembly, the crossbeams are placed on the support surface or marking, supported in a supportive manner, and secured to the central beam with a fastener, preferably a screw. The screw is preferably attached to a mounting rail. The support surface or marking can also be applied with paint or as lines on the surface of the central beam.

[0026] In another embodiment, the central beam has no grooves on its surface, but the crossbeams have grooves on the underside that can accommodate raised sections of the central beam. This allows the crossbeam to be easily attached to the central beam.

[0027] The height of the central beam, or the distance from the underside of the central beam to the bottom surface of the groove or the support surface on the central beam, is selected such that the distance of the solar panel from the flat roof surface complies with legal requirements. For a green roof, the distance from the top edge of the solar panel to the flat roof surface is at least 25 cm; for a gravel roof, the distance from the top edge of the solar panel to the flat roof surface is at least 15 cm. The central beam is preferably 2 to 10 meters long, preferably 2 to 6.5 meters, and preferably weighs 100 to 700 kg, preferably 160 to 550 kg. The central beam is preferably placed and positioned on the flat roof using a crane.

[0028] In one embodiment, the crossbeams have a consistently rectangular or square cross-section and the same cross-section over their entire length. However, the crossbeams can also have another elongated shape and the cross-section can vary over their length. A substantially rectangular cross-section is particularly preferred, with the narrower longitudinal side preferably forming the mounting surface for attaching the solar panels. The elongated crossbeams preferably have a length of 100 to 150 cm and a width of 10 to 20 cm. The weight of the crossbeams is, for example, 10 to 20 kg, preferably 16 kg - 17 kg, and the crossbeams are easily carried and transported by hand by one person.Preferably, the crossbeam with a rectangular or square cross-section is inserted in a groove in a form-fitting manner, wherein the groove has a bevelled bottom surface with an angle of inclination which corresponds to the angle of inclination of the mounting surface of the crossbeam.

[0029] Preferably, each crossbeam has at least one opening for receiving fastening means with which the crossbeam is fastened to the central beam. Suitable fastening means can be screws or adhesives, for example. The crossbeam is particularly preferably screwed to the central beam. Preferably, the central beam has mounting rails in the groove or in the region of the support surfaces, to which mounting rails the fastening means of the crossbeam are fastened. Preferably, the crossbeams are screwed to a mounting rail of the central beam using a screw. Preferably, the crossbeam is fastened centrally to the crossbeam and from the central beam to the central beam. Preferably, the opening for receiving fastening means is a through-hole in the crossbeam and is arranged centrally, in the center of the transverse and longitudinal axes of the crossbeam, extending from the mounting surface to the underside of the crossbeam.

[0030] In a further embodiment, the crossbeam has a substantially gable-shaped form in longitudinal section, i.e., the shape of a flat isosceles triangle or gable, also called a flat triangular gable, wherein the mounting surface for attaching the solar panels is arranged on the sides of the triangle or the gable or gable cornice, and the gable is arranged above the central axis of the central beam. Such crossbeams are referred to as gable-shaped crossbeams. In this embodiment, the solar panels are mounted on both sides of the gable. These gable-shaped crossbeams have, for example, a length of 200 to 250 cm, a height of 20 to 30 cm, preferably 25 to 30 cm, and a width of 10 to 20 cm, preferably 10 to 15 cm, and have a weight of 30 to 50 kg, preferably 35 to 45 kg, and are easily portable, transportable and assembled by two people.

[0031] In one embodiment, the solar panels are attached upright to the crossbeams or are mounted upright. By upright or upright is meant that the long sides of the solar panel in this type of installation are arranged to the sides and the transverse sides are arranged at the top and bottom in relation to the angle of inclination. The long side of the solar panel is each attached to a crossbeam. The crossbeams are preferably arranged between the solar panels or in the transition between two solar panels and at the end of the first and last solar panel in a row, which are mounted on a modular substructure. For this type of installation of the solar panels, one more crossbeam is required than solar panels are mounted, since a crossbeam is arranged at the beginning of the first and at the end of the last solar panel in a row and between each solar panel.Therefore, mounting five solar panels requires six elongated crossbeams. Ideally, the distance between the crossbeams, from the central longitudinal axis of one crossbeam to the central longitudinal axis of the adjacent crossbeam, should be approximately the width of one solar panel.

[0032] With gable-shaped crossbeams, twice as many solar panels can be mounted, as the solar panels can be mounted on both sides of the gable-shaped crossbeams. This means that for the installation of ten upright solar panels, six gable-shaped crossbeams are required. In another embodiment, the solar panels are attached horizontally to the crossbeams, or are mounted horizontally. Horizontal or horizontal means that the shorter transverse sides of the solar panels are arranged to the sides and the long sides are arranged at the top and bottom in relation to the angle of inclination of the solar panels. The transverse side of each solar panel is attached to a leg of the gable-shaped crossbeam. For the installation of horizontally arranged solar panels, twice the number of elongated crossbeams is required, i.e.two elongated cross beams per solar panel, or in the case of gable-shaped cross beams, the same number of gable-shaped cross beams are required as solar panels are mounted.

[0033] The crossbeams are preferably arranged such that, in each embodiment, one solar panel is supported by two crossbeams. A solar panel, also called a solar module, photovoltaic module, or solar plate, is understood to be an assembly of many individual solar cells in which electrical energy is generated by the irradiation of sunlight. The coupling of several solar panels results in a solar or photovoltaic system. The substructure according to the invention can be adapted to any desired size of solar panel. For example, a solar panel has a length of 170 to 190 cm and a width of 90 to 120 cm.

[0034] The mounting surface is defined as the long side of the crossbeam on which additional fastening elements, such as clamps or screws on mounting rails, are attached. These clamps are used to attach the solar panels to the crossbeam. The fastening elements for attaching the solar panels to the mounting surface are preferably arranged at the two head ends of the elongated crossbeams or at the head ends and on both sides of the gable of the gable-shaped crossbeams and are preferably designed as screws or clamps that are attached to mounting rails. The solar panel is preferably clamped between two clamps, which in turn are then screwed to the mounting rails on the crossbeam. The clamps are preferably made of metal.If the solar panels are mounted upright or vertically, preferably on elongated crossbeams with a rectangular or square cross-section, the solar panels are clamped between two clamps at the ends of the long sides, and the clamps are aligned along the long side of the solar panels, parallel to the length of the crossbeams, so that four clamps are required per solar panel. If the solar panels are mounted horizontally or crosswise, preferably on gable-shaped crossbeams, the solar panels are clamped between two clamps at the ends of the top and bottom long sides, and the clamps are aligned parallel to the long side of the solar panels and perpendicular to the length of the crossbeams, so that four clamps are required per solar panel.The angle of inclination of the mounting surface relative to the horizontal, the flat roof surface, or the supporting surface of the central beam corresponds to the desired angle of inclination of the solar panels to be installed. The inclination of the supporting surface of the central beam corresponds to the inclination of the flat roof surface.

[0035] The modules, i.e. both the central beam and the cross beams, are made of lightweight concrete and preferably have a bulk density of less than 1200 kg / m3. A bulk density of 500-900 kg / m3 is particularly preferred. The modules are preferably manufactured as individual cast molds from lightweight concrete. The lightweight concrete preferably has reinforcements made of glass fiber reinforced plastic (GRP). The GRP reinforcing bars are preferably arranged along the longitudinal axis of the cross beams or the central beam. These are completely rust-proof and cannot be destroyed by environmental influences. The lightweight concrete preferably has aggregates made of expanded clay, expanded glass, expanded slate, or pumice. Aggregates made of expanded glass are particularly preferred, and recycled glass is even more preferred.In a further, particularly preferred embodiment, the lightweight concrete additionally comprises plastic fibers, preferably polyolefin-based bi-component plastic macrofibers, which give the lightweight concrete additional stability.

[0036] By using the lightweight concrete described here, it is possible to easily produce particularly light and stable cross beams and central beams as modules for the modular substructure. The CO 2Emissions kept low. The individual modules can be transported and installed easily, i.e. the central beam with a crane and the cross beams by one or two people by hand, and yet they are sufficiently stable and have a sufficiently high dead weight so that the substructure produced in this way can be set up freely on a flat roof at any location without additional fastening to the subsurface, in particular the flat roof. This means that the modular substructure according to the invention can be attached to a flat roof in a slip-proof and storm-proof manner even without fastening and is protected against the effects of the weather, in particular storms, without additional fastening or loading elements. A further advantage is that the existing roof coverings such as gravel, earth or substrate on existing roofs do not have to be removed beforehand in order to attach fastening mechanisms for the substructure.This also saves time because the exact location doesn't need to be measured in advance, eliminating the need for complex fastening mechanisms. Likewise, the modular substructure and individual modules can be easily removed and reinstalled if roof renovation becomes necessary.

[0037] The invention also relates to a method for mounting solar panels on a flat roof, wherein a substructure according to the invention is used, and the method comprises the following steps:

[0038] (A) Placing the central beam with the flat surface facing downwards on a flat roof such that the flat surface rests on the flat roof surface,

[0039] (B) Inserting the cross beams into the grooves of the central beam, or supporting the cross beams on the support surfaces on the central beam;

[0040] (C) Attaching the cross beams to the central beam; and

[0041] (D) Attach the solar panels to the mounting surfaces of the cross beams.

[0042] The modular substructure made of lightweight concrete according to the invention makes it possible to apply the necessary load of 100 kg per solar panel, ensuring that the structure is both light enough for transport and installation and has sufficient deadweight to rest securely on the flat roof during storms. A substructure for five solar panels therefore weighs an average of approximately 500 kg.

[0043] In addition, no scaffolding is required to install the modular substructure on the flat roof, as is the case with conventional structures. The modular substructure according to the invention can be easily placed on the flat roof with the help of a crane and erected without scaffolding. Preferably, the individual cross beams are placed together on a pallet, and the central beam is placed separately on the flat roof, positioned, and then assembled on-site. Upon request, the substructure can also be delivered fully assembled and positioned at the desired location on the flat roof.

[0044] Another advantage is that the modular substructure with a central beam applies linear loads to the roof, rather than the point loads associated with conventional structures. This reduces the roof's localized loads and reduces the risk of a leak on the flat roof. The roof is therefore less susceptible to damage or subsidence, and the modular substructure can be removed or reinstalled in the event of a roof renovation.

[0045] Another advantage of the modular substructure is that the inclination angle of the mounting surface of the crossbeams corresponds to the desired inclination angle of the solar panels in every design. Depending on the desired inclination angle of the solar panels, preferably between 10 and 30 degrees relative to the horizontal or relative to the slope of the flat roof surface, modular substructures are ordered and installed with the desired inclination angle of the mounting surface. This means that the inclination angle is already preset, and the solar panels can be easily mounted on the substructure without adjusting the inclination angle. This saves additional time. Since time can be saved in various steps, installation is about five times faster and thus much more economical than with conventional substructures.

[0046] Combinations of two or more of the above-mentioned embodiments and variants are conceivable and claimed. Further advantages of the invention will become apparent from the following description, in which the invention is explained in more detail with reference to exemplary embodiments illustrated in the drawings.

[0047] Short description of the characters

[0048] They show:

[0049] Fig. 1 a substructure in perspective view from above with partially mounted solar panels and elongated cross beams, partly before assembly,

[0050] Fig. 2 the substructure of Figure 1 in perspective view with elongated crossbeams from diagonally above,

[0051] Fig. 3 a perspective view from below of a substructure with transversely mounted solar panels,

[0052] Fig. 4 is a partial sectional view across the substructure of Fig. 1 ,

[0053] Fig. 5 another substructure in perspective view from below with gable-shaped crossbeams and transversely mounted solar panels,

[0054] Fig. 6 another substructure in perspective view from below with gable-shaped cross beams and transversely mounted solar panels and raised central beam, and

[0055] Fig. 7 shows a perspective view of a flat roof with solar panels mounted on substructures according to the invention. In the figures, the same reference numerals are used for the same elements, and explanations of a specific reference numeral apply to all figures unless expressly stated otherwise.

[0056] Embodiments of the invention

[0057] Figure 1 shows an oblique view from above of a substructure 1 with several elongated cross beams 4 measuring 12 x 12 x 120 cm and a longitudinal central beam 5 with a bottom side 12 and a top side 12. The central beam connects the cross beams 4 to one another and has a protective layer 7 on the bottom side 12 to protect against injuries on the flat roof surface (not shown). The underside of the protective layer 7 forms the supporting surface 19. The elongated cross beams 4 have a continuous square or rectangular cross-section and each have a mounting surface 10 for attaching the solar panels 2, wherein the mounting surface 10 has an angle of inclination ß relative to the horizontal or the supporting surface 19 of the central beam 5, which corresponds to the angle of inclination of the solar panels 2.The central beam 5 has a plurality of grooves 6 on its upper side 13 for receiving the cross beams 4, in which the cross beams 4 are positively inserted after assembly. In this figure, the two cross beams 4 on the right are shown shortly before assembly and slightly above the nut 6. The bottom surface of the groove 14 corresponds to the support surface 18 on which the cross beams are supported after assembly. Each cross beam 4 has an opening 8 in the form of a hole in the center of the mounting surface 10, which serves to receive a screw, by means of which the cross beams 4 are fastened to the central beam 5. The screw head is slightly countersunk in the hole such that the upper end of the screw head lies lower or at most at the same height as the mounting surface.The mounting surface 10 of the crossbeams 4 has mounting rails 16 at both ends, to which fastening elements 11 in the form of clamps for fastening the solar panels 2 are screwed. In this embodiment, the solar panels 2 are mounted upright on the crossbeams 4 with the short transverse sides along the central beam 5 and the long sides along the crossbeams 4. The upright solar panels 2 are each clamped at the upper ends of the long sides between two metal clamps as fastening elements, which are each arranged at the ends of the crossbeams 4 and fastened to mounting rails by means of hammer-head bolts or nuts.

[0058] The central beam 5 and the cross beams 4 are all made of lightweight concrete and are therefore easy to transport and install on a flat roof. For installation, the central beams 5 and cross beams 4 are preferably placed on a flat roof (not shown) using a crane, and the central beam 5 is placed in the desired location without being secured. The cross beams 4 are then inserted into the prefabricated beveled grooves on the roof and fastened with a screw. The positioning of the cross beams 4 and the angle of inclination do not need to be measured, since the angle of inclination of the groove 6 already corresponds to the desired angle of inclination of the solar panels 2, and the distance between the cross beams 4, i.e. from the central axis of one cross beam 4 to the central axis of the adjacent cross beam 4, already corresponds to the desired width of the solar panels 2, including the fastening clamps. The solar panels 2 are then attached to the cross beams 4 using the fastening devices 11.This means that the placement of the solar panels 2 does not have to be measured, which saves a lot of time.

[0059] Figure 2 shows the substructure 1 as shown and described in Figure 1 without installed solar panels. The angle of inclination ß of the mounting surface 10 relative to the horizontal or the underside 12 of the central beam 5 is shown again.

[0060] Figure 3 shows a substructure 1 with a raised central beam 5 viewed diagonally from below. The substructure 1 has a central beam 5 and six elongated cross beams 4 with a rectangular cross-section, wherein the cross beams 4 are inserted into the bevelled grooves 6 and supported in a form-fitting manner. The transverse solar panels 2 are fastened to the cross beams 4 on the transverse sides with fastening means 11 in the form of clamps, wherein the clamps are arranged such that they are rotated transversely to the longitudinal axis of the cross beams 4 and the solar panels are clamped between the clamps at their upper and lower edges. The central beam 5 has a greater height than the central beam 5 in Figure 1 . A greater height and thus also a greater distance between the solar panels and the flat roof surface is desired, in particular for green flat roofs, where the required minimum distance between the solar panel and the flat roof must be maintained.The underside 12 of the central beam 5 forms the supporting surface 19 for support on a flat roof.

[0061] Figure 4 shows a partial sectional view of the transverse side of a substructure 1 or transversely through the substructure 1 as described in Figure 1. The substructure 1 has a central beam 5 with a rectangular cross-section and a protective layer 7 on the underside 12 of the central beam 5, wherein the underside of the protective layer 7 forms the supporting surface 19 for resting on a flat roof (not shown). The elongated crossbeam 4 is fastened to the central beam 5 by a screw 9, wherein the screw 9 is designed such that the thread protrudes through a hole in the crossbeam 4 into the central beam 5 and the screw head is also countersunk in the crossbeam such that the top side of the screw head is flush with the mounting surface 10. The solar panels 2 are clamped between metal clamps 11 which are screwed to the crossbeam 4 by screws.The metal clamps 1 1 are arranged on both sides at the head ends of the elongated crossbeam 4 and on the sides of the solar panels 2, longitudinally to the longitudinal direction of the crossbeam 4.

[0062] Figure 5 shows another substructure 1 with a central beam 5 with a continuous protective layer 7 on the underside 12 and gable-shaped crossbeams 4' measuring 12x28x220 cm. The underside of the protective layer 7 forms the supporting surface 19 for support on a flat roof (not shown). The gable-shaped crossbeams 4' have the cross-section of a gable or a flat isosceles triangle. The mounting surface 10 for attaching the solar panels 2' is arranged on the sides of the triangle or the gable 15 or gable cornice, and the gable 15 is arranged above the central axis Z of the central beam 5. The central beam 5 has six recessed, horizontal grooves 6' into which the gable-shaped crossbeams 4' are inserted with their horizontal base surface and positively mounted. In addition, the gable-shaped cross beams 4' are screwed to the central beam using screws (not shown).In this embodiment, the solar panels 2' are mounted on both sides of the gable 15. The two transverse sides of a solar panel 2' are each attached to a leg of the gable-shaped crossbeam 4', with metal clamps being used as fastening means 11. The metal clamps are arranged at the head ends and on both sides of the gable 15 of the gable-shaped crossbeams 4'. The solar panels 2' are arranged or mounted horizontally and are each clamped at the ends of the long sides of the solar panels 2' between two metal clamps. The metal clamps are aligned parallel to the long side of the solar panels 2' and transversely to the longitudinal direction of the crossbeams 4', so that four clamps are required per solar panel. This Figure 5 shows six gable-shaped crossbeams 4' and six horizontal solar panels 2'.

[0063] Figure 6 shows a substructure 1 as described in Figure 5 in a perspective view from below. In contrast to the substructure 1 in Figure 5, the central beam 5 has only slightly recessed horizontal grooves 6', and the gable-shaped crossbeams 4' are barely inserted into the grooves. By screwing them together with screws (not shown), the crossbeams 4' are nevertheless sufficiently fastened to the central beam 5. In this embodiment, the distance between the solar panels 2' and the flat roof surface (not shown) is greater than in the embodiment shown in Figure 5. For additional stabilization of the long crossbeams 4', support elements 17 in the form of concrete posts can be arranged under the head ends of the gable-shaped crossbeams. Figure 7 shows a flat roof 3 on which various substructures 1 for solar panels 2, 2', as shown in Figures 1 and 5, are shown in a perspective view from above.In this case, upright solar panels 2 are mounted on elongated cross beams 4. Two rows, each with nine solar panels 2 and ten elongated cross beams 4 on a central beam 5, are shown, as well as one row with eight solar panels 2 on nine elongated cross beams 4. In addition, a substructure 1 is shown as described in Figure 5 with a central beam 5 and six solar panels 2' on six gable-shaped cross beams 4'. The solar panels 2, 2' can be deposited and mounted on a flat roof 3 without scaffolding and without attaching the substructures 1 to the flat roof 3. In the event of roof renovation, the solar panels 2, 2' and the substructures 1 can be easily dismantled and reassembled later.

[0064] List of reference symbols

[0065] 1 Modular substructure

[0066] 2 standing solar panels

[0067] 2' horizontal solar panel

[0068] 3 flat roof

[0069] 4 elongated crossbeams

[0070] 4' gable-shaped crossbeam

[0071] 5 central beams

[0072] 6 groove with bevelled bottom surface / bevelled groove

[0073] 6' groove with horizontal base surface / horizontal groove

[0074] 7 Protective layer

[0075] 8 Opening

[0076] 9 Fasteners

[0077] 10 Mounting surface

[0078] 11 Fastening element of the solar modules

[0079] 12 Underside of the central beam

[0080] 13 Top of the central beam

[0081] 14 Bottom surface of the groove

[0082] 15 Gable or spire

[0083] 16 mounting rail

[0084] 17 Support element

[0085] 18 support surface

[0086] 19 flat surface, supporting surface ß Angle of inclination between the horizontal or flat roof surface and the

[0087] Mounting area or the area of ​​the solar panel

Claims

Patent claims 1. Modular substructure (1) made of concrete for solar panels (2, 2') for installation on a flat roof (3), comprising a plurality of cross beams (4, 4'), wherein the cross beams (4, 4') each have a mounting surface (10) for fastening the solar panels (2), and wherein the mounting surface (10) has an angle of inclination ß with respect to the horizontal, which corresponds to the angle of inclination of the solar panels (2, 2'), characterized in that the substructure (1) has a longitudinally directed central beam (5) with a bottom side (12) and a top side (13), wherein the bottom side (12) of the central beam (5) is designed as a flat surface (19) for resting on a flat roof (3), wherein the one central beam (5) connects the plurality of cross beams (4, 4') to one another and on the top side (13) a plurality of grooves (6, 6') and / or support surfaces (18) for receiving the cross beams (4, 4') so that the cross beams (4, 4') fit positively in the grooves (6,6') and / or are mounted on the support surfaces (18) and are fastened to the central beam (5), and wherein the central beam (5) and the cross beams (4, 4') are made of lightweight concrete., 2. Modular substructure (1) according to claim 1, characterized in that the groove (6, 6') has a rectangular cross-section.

3. Modular substructure (1) according to claim 1 or 2, characterized in that the bottom surface (14) of the groove (6) and / or the support surface (18) for receiving the crossbeams (4) is bevelled and has an angle of inclination ß which corresponds to the angle of inclination of the mounting surface (10) of the crossbeams (4).

4. Modular substructure (1) according to claim 1 or 2, characterized in that the bottom surface (14) of the groove (6') and / or the support surface (18) for receiving the cross beams (4) is horizontal and corresponds to the inclination of the underside (12) of the central beam (5).

5. Modular substructure (1) according to one of the preceding claims, characterized in that the cross beams (4, 4') are screwed into the central beam (5).

6. Modular substructure (1) according to one of the preceding claims, characterized in that the cross beams (4, 4') are fastened to the central beam (5) by fastening means (9) centrally from the cross beam (4, 4') and from the central beam (5).

7. Modular substructure (1) according to one of the preceding claims, characterized in that the longitudinal central beam (5) is a continuous beam, and that a single longitudinal continuous central beam (5) connects all several cross beams (4, 4') to one another.

8. Modular substructure (1) according to one of the preceding claims, characterized in that the cross beams (4, 4') are arranged at a right angle to the longitudinal central beam (5).

9. Modular substructure (1) according to one of the preceding claims, characterized in that the distance of the crossbeams (4, 4') from the central longitudinal axis of one crossbeam (4, 4') to the central longitudinal axis of the adjacent crossbeam (4, 4') corresponds to the width of a solar panel (2, 2').

10. Modular substructure (1) according to one of the preceding claims, characterized in that the lightweight concrete has a bulk density of less than 1200 kg / m3, preferably of 500 - 900 kg / m3. 1 1. Modular substructure (1) according to one of the preceding claims, characterized in that the lightweight concrete has reinforcements made of glass fiber reinforced plastic (GRP) and plastic fibers.

12. Modular substructure (1) according to one of the preceding claims, characterized in that the lightweight concrete comprises aggregates made of expanded glass.

13. Modular substructure (1) according to one of the preceding claims, characterized in that the central beam (5) has a protective layer (7) on the underside (12) for resting on a flat roof (3).

14. Modular substructure (1) according to one of the preceding claims, characterized in that the mounting surface (10) of the cross beams (4, 4') has fastening elements (11) on both sides of the ends thereof for fastening the solar panels (2, 2').

15. A method for mounting solar panels (2, 2') on a flat roof (3), characterized in that a substructure (1) according to one of the preceding claims is used, the method comprising the following steps: (A) Placing the central beam (5) with the flat surface (19) facing downwards on a flat roof (3) such that the flat surface (19) rests on the flat roof surface, (B) Inserting the cross beams (4) into the grooves (6, 6') of the central beam (5) or supporting the cross beams (4') on the support surfaces (18) of the central beam (5); (C) attaching the cross beams (4, 4') to the central beam (5); and (D) Attach the solar panels (2, 2') to the mounting surfaces (10) of the crossbeams (4, 4').

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