A solar roof for more independence from the grid
A distinction is made between on-roof systems and in-roof systems. In on-roof systems, the solar modules are mounted on the roof of the house with the help of a mounting frame. The angle of inclination can also be easily optimized for pitched roofs. It is the simplest and most common way to install a PV system. Mounting frames are usually specifically designed for different roof types such as sheet metal roofs, tiled roofs, slate roofs and roofs made of corrugated sheet metal. An additional advantage is natural ventilation of modules through the gap between roof and panel. We advise you to choose a truly weather-proof mounting system to avoid unpleasant surprises.
Flat roofs usually have only a small inclination or none at all. Therefore, the solar modules should be angled at least 6° through the mounting system. A tilt of up to 13° is possible and recommended.
With an in-roof system, solar modules replace the standard roof tiles. This is more pleasing to the eye and weatherproofs the system at the same time. The downside is that installing them is more complex and therefore more expensive. The cooling of in-roof solar modules is also more complex than with an on-roof system and reduces the efficiency by about 0.5%. In-roof systems are only suitable for tiled roofs that are designed as pitched roofs with a relatively large inclination, as otherwise the efficiency is severely impaired. This solution is not possible for sheet metal or bitumen roofs.
Mini systems for carport, garage, facade (and satellites)
A mini PV system requires only one to two square meters of space. This makes it ideal for carports, the facade or a summer house. You can produce up to 600 W of electrical power with them, depending on the solar modules used. The only technical requirement is that the respective roof or facade must be stable enough to support the weight of the solar modules plus mounting system.
You can use the electricity produced to charge your electric car, hybrid plug-in or similar. Of course, you can also use the electricity in your household and thus reduce your electricity bill. However, you usually cannot produce all the electricity required for a household with a mini PV system. Before planning your PV system, you should also find out if your local building authority imposes any restrictions.
Ground-mounted PV systems (solar parks)
For installing a PV system, you don’t need a roof or even a house. As a PV fan you surely know the impressive pictures of huge solar farms or “parks”. Here, too, mounting systems are in use to keep the modules in place. There are two fundamentally different mounting systems for solar farms: fixed mounting and tracking systems.
Free-land PV systems
For fixed mounting systems a steel or aluminum frame is screwed onto concrete blocks or anchored into the ground. The inclination and orientation of the modules cannot be changed after installation.
The fixed ground-mounted system has several advantages compared to a roof-mounted system:
- There is usually more space available.
- The orientation can be chosen freely and is not determined by a roof.
- This also means that the inclination can be adjusted almost at will.
- More space also means more modules. Here it is also worthwhile using modules with lower efficiency, which are cheaper to buy.
With tracking systems, the modules track the orientation of the sun. Tracking systems are available with single-axis and two-axis tracking. With single-axis tracking, the orientation of the modules changes either horizontally or vertically depending on the position of the sun. Horizontal tracking follows the position of the sun from east to west. Vertical tracking aligns the modules to the south and rotates – depending on the height of the sun’s position – over the horizon. The two-axis tracking is a combination of horizontal and vertical tracking.
Advantages of the tracking system:
- The power yield of the PV system increases significantly compared to fixed mounting.
- In Central Europe alone, the increase in power yield is 20% with single-axis tracking and 30% with two-axis tracking.
Disadvantages of the tracking system:
- Higher investment costs.
- The system requires more maintenance. This increases operating costs.
- The tracking system requires electricity.
floating PV system
A special form of installation is the floating PV system, for which the solar modules are mounted on flotation devices usually made from plastic. The investment costs are 20% to 25% higher than those of a conventional installation on solid ground.
PV systems connected to the public grid
Grid-connected systems bear their name because they are connected to the public power grid. The majority of all installed PV systems are grid-connected systems.
Non-coupled off-grid systems
There are also PV systems that are not connected to the public grid. Since this also means that there is no possibility of feeding into the public grid, these systems are usually connected to a battery.