Large commercial and industrial roofs are ideally suited for the inexpensive and ecological generation of electricity through PV roof systems. These systems consist of solar modules that are mounted on the roof and capture sunlight to generate electricity. In addition to the solar modules, the Substructures for PV roof systems the most important elements that are mounted on the roofs and thus have a not inconsiderable influence on the Total roof load have. They should therefore always be selected appropriately and carefully.
Why the selection of substructures for PV roof systems is important
Choosing the right substructure for the PV roof system is crucial to the success of a solar installation. A well-designed substructure provides the necessary Stability and Security for your solar modules. It also helps to distribute the load on your roof and minimize possible Prevent damage. An incorrect substructure can lead to instability, damage to the roof and even failure of the entire PV system.
Types of substructures for PV roof systems
There are different types of substructures that can be used for PV roof systems. The most common are
- Roof-mounted systemsThese substructures are installed on the existing roof and the solar modules are mounted on them. They are easy to install and are well suited to flat roofs.
- In-roof mounting systemsThese substructures are integrated into the roof and the solar modules are installed directly into the roof. They offer a more aesthetically pleasing solution, but require careful planning and installation.
- Free-standing mounting systemsThese substructures are erected independently of the roof and the solar modules are mounted on them. They are well suited for large areas or plots where there is no roof.
- Special solutionsthat are particularly light or can be mounted flexibly. Substructures and elevations that do not require any ballast or roof penetration are also possible. Such mounting systems are often used for older commercial and industrial roofs.
What loads must substructures withstand?
Substructures for companies' PV roof systems must be able to withstand various loads. The most important loads include
- Gravity loadThe substructure must be able to support the weight of the solar modules without deformation or damage.
- Wind loadThe substructure must be designed to withstand strong winds to ensure the stability of the solar modules.
- Snow loadIn areas with heavy snowfall, the substructure must be able to bear the weight of the snow to prevent damage to the roof cladding.
- Temperature loadThe substructure must be able to withstand temperature fluctuations without deformation or damage.
How does the substructure influence the roof load of PV roof systems?
A decisive factor that can reduce the roof load of the entire PV roof system is therefore the choice of suitable substructures. The roof load is the load that a roof can bear without damage. It is crucial to determine the roof load of the building before installing photovoltaic systems to ensure that the roof can support the planned load. If the Results of the structural analysis test If it turns out that the required load is exceeded by the installation of a standard solar system, ways must be found to reduce the roof load of a PV system.
The roof load of a photovoltaic system depends on various factors, such as the size of the system, the module weight and the mounting system. A photovoltaic system with monocrystalline modules, for example, will be heavier than a system with thin-film modules. The roof construction of the building also plays a role, as certain roof types can bear a higher load than others. In general, a Roof load reserve depending on the condition of the roof between 10 and 24 kg/m² recommended.
Typically, commercial or industrial roofs can support a load of around 100 kg per square meter. This means that a photovoltaic system that weighs a total of 20 kg/m², for example, can be installed on a roof with a roof load of 100 kg per square meter without any problems. Nevertheless, the load-bearing capacity of the roof itself should always be taken into account, especially in the case of older roofs or those with poor construction.
Particularly lightweight substructures for PV roof systems
One system that allows PV systems to be mounted on commercial and industrial roofs with a low roof load reserve, for example, is firmly welded to the roof cladding. It enables precise positioning of the modules on the roof surface and provides lift-off protection without placing additional ballast on the outer or top layer and the underlying statically stressed roof structure. The system can be used in almost any standard outer skin such as bitumen, PVC, FPO/TPO. The flexible fastening collars are simply adapted to the material.
Depending on the selected substructure of the PV system, the mounting points for the support racks are positioned so that they can be easily fastened with a stainless steel screw in the center of the bearing point. All mounting elements of the substructure are made of stainless materials and the bearings are made of specially developed, weather and UV-resistant plastic. All support points can be positioned individually and have a weight of only 600 gram. The entire weight of the modules ultimately rests on a Stainless steel plate with 20 cm diameterThis means that no pressure mats or other protective materials are required.
This particularly lightweight substructure for PV roof systems is not only suitable for flat commercial and industrial roofs, but also for Pitched roofs up to 10° pitch. Compared to a conventional elevation, this can up to 50% weight saving so that a roof upgrade or renovation is not necessarily required.
Other factors to consider when selecting substructures
The type, pitch and condition of the roof play a decisive role, as the substructure must be adapted to these characteristics in order to ensure efficient installation and performance of the solar system.
The site conditions are also of great importance. Wind and snow loads and the climatic conditions at the location influence the choice of substructure for PV roof systems. A robust construction may be necessary to withstand local weather conditions and ensure the long-term reliability of the PV system.
Aesthetic requirements also play a role, especially if the appearance of the company building is important. The substructure can be seamlessly integrated into the architecture of the roof to provide an aesthetically pleasing solution.
Unlike the Contracting is at the Purchase of a PV roof system, the budget is another factor, whereby the share of the substructure in the total costs is usually five to ten percent is. Depending on the size of the commercial photovoltaic system, the expenditure for this item can quickly run into five or six figures. Therefore, the financial possibilities should be taken into account in order to select a substructure that both meets the technical requirements and is within the financial framework of the company.
Generally speaking, on-roof mounting systems are usually more cost-effective as they are easier to install and require less material. In-roof mounting systems can be more expensive due to their more complex integration and installation. Free-standing mounting systems have variable costs depending on location and system size.
Conclusion
Choosing the right substructure for a commercial PV roof system is crucial to the success of a solar installation. When planning a PV project, the different types of substructure should be discussed in advance and the specific requirements of the roof and location should be taken into account. Careful selection ensures that the PV roof system is safe, stable and efficient. When selecting the appropriate substructure, the roof load reserve should always be taken into account and the costs must be weighed against a roof upgrade or necessary renovation. It is always possible to reduce the roof load, at least by choosing lighter substructures in combination with lighter solar modules. In any case, an independent roof check is always helpful when making a decision.