When deciding about the optimal mounting location for solar modules the following criteria should be considered:
- To which extent does the place receive high radiation of sunlight?
- is it free of shading?
- is it not exposed to dust and other particles which may cover or damage the modules?
- will the modules be exposed to excessive heat?
- does the place offer protection against theft and vandalism?
- is it close to the battery?
Solar modules can be mounted in a fixed, flexible or tracking way.
Fixed modules (either as single module or as array of several modules) are mounted on:
Fixed mounting structures tilt the modules at a fixed angle determined by the latitude of the site, the requirements of the load (appliances which are powered by the PV power system) and the availability of sunlight. The fixed mounts should be stable, flat and well ventilated. They must withstand heavy wind and heavy rainfall.
Flexible system use basically the same mounting structures, but the modules are removable.
Tracking structures are more expensive and require higher maintenance efforts. The trackers orient the modules towards the Sun, thus increasing their output.
Mounting (Pole / Roof / Free-standing / Building Integrated)
Modules that are mounted on a pole are easy to install an can be easily oriented towards the Sun. They can be free-standing or installed on the side of a building. Usually, a small array of one or to modules is mounted per pole. Thus, pole mounting is suitable for small solar home systems, especially, if the roof support structure of the house is not stable enough to support a PV array.
For roof mounting the most common support structure consists of racks. It is important to leave a space of at least 10 cm between the roof and the array to allow ventilation. Otherwise, the array gets too hot and the performance of the modules decreases. The mounting structure must be fixed to the building or the under-roof beams to ensure durability and safety.
Free-standing arrays on a ground support, usually consisting of racks, are easy to install and to orient towards the Sun. It might be difficult to avoid shading and therefore, enough space is needed to install the array far from trees, buildings and other objects that might cast shadows on it. The modules are easily accessible which is beneficial for maintenance, but could also imply a higher risk of theft.
Building-integrated PV arrays consist of thin film modules. This kind of mounting structure is not common in off-grid installations.
Mounting Structure Materials
Mounting structures can be made of:
- galvanised steel,
- painted steel,
- aluminium or
There is a vary large offer of factory-made mounting structures available on the market, but it is usually possible to produce them locally, too. It is important that mounting materials are corrosion-resistant and weather proof.