Estructuras fotovoltaicas

¿Qué son, qué tipos hay y cuáles son los problemas derivados?
22 de octubre de 2021 por
Estructuras fotovoltaicas
Techno Sun, SLU, Hugo Rodrigo Zapata :

The importance of solar panel structures

The photovoltaic structure is an essential element of any installation since it is responsible for holding the solar panels correctly, ensuring protection against wind, snow and other inclement weather conditions, as well as providing the precise orientation and the ideal angle to make the most of solar radiation.

That is why the two fundamental aspects when mounting a solar structure are its location and its placement. 

Location of photovoltaic structures

The Solar structures must be positioned with the appropriate orientation and inclination where they can be free of shadows during the central hours of the day. However, this may not always be possible due to particular situations arising, for example, from architectural integration.

Placement of photovoltaic structures

The placement of the structures is an important point that varies in complexity depending on the surface and the place where they are installed, although an installation on the ground will normally be much simpler than one on a sloping roof. It is always advisable to make a study and plan the installation in advance, in order to have all the necessary materials and safety measures. The installation of the structure can be divided into two parts: assembly and anchoring.

The first consists of the joining and mechanical fastening of the different parts of the structure, such as the profiles, the zeta, etc.

Anchoring, on the other hand, is the fixing of the structure to the surface or to the supporting elements, whether it is the floor, roof, facade, etc. In this way, the structure will have the necessary stability and resistance to support the photovoltaic modules and the inclement weather.

It must be taken into account that this type of work can be of considerable size and may require specific permits depending on the regulations of the place where it is carried out.

Fixed photovoltaic structures

The fixed solar panel structure is one of the most common structure systems in solar installations.

Within them, we could distinguish four fundamental ways of locating the photovoltaic moduleson the ground, on poles and/or metal towers,  on walls and on roofs.

Photovoltaic structures on the ground

The assembly of structures on the ground has a number of important advantages, especially with regard to maintenance and wind action, since the modules are usually located at a short distance from the ground, which prevents them from being greatly affected by the wind. Although it will always be necessary to leave a minimum height of security to avoid that in case of torrential rains or big snowfalls the panel can be covered.

As a disadvantage we can find that it is necessary to look for a location away from other elements that produce shadows on the panels. As they are located on the ground instead of in an elevated place, it is easier for trees or other buildings to cast shadows on them. This can cause a series of dangers on the panel as we have already commented in the blog: Shading in photovoltaic systems.

Photovoltaic structures on poles

This type of installation is usually suitable when low shadows are to be avoided or when installation on the ground is not possible due to the terrain.

t is more common to use this type of structure for one or two panels, not for larger installations, and they are usually more related to powering repeaters, solar pumping or other isolated systems that do not require a large amount of energy. 

The main disadvantage of this type of installation is related to maintenance, as it is usually not easy to access the panel.

Photovoltaic structures on facades

In this type of installation, the structure is used when the wall faces south, otherwise the energy production would drop significantly.

It is attached to the wall thanks to a system of claws, and thanks to its location close to the facade, the action of the wind on the facade is reduced.

As with the floor installation, care must be taken to avoid areas that may be affected by shadows from other elements.

Rooftop photovoltaic structures

This type of installation is perhaps the most common, with the exception of solar farms, for all types of installations. The structure is placed on the roof or the roof of the buildings, in this way it is easier to orient them and take advantage of the space of the building itself.

It will be necessary to make a previous study in order to optimize the orientation and inclination, since not all roofs are in the best possible places, and may have slopes less than adequate, so it is important to increase this to optimize energy production and avoid the accumulation of dirt, with the problems that this entails, as explained in the blog: The danger of dirt on solar panels.

Two important points when carrying out this type of installation are the care that must be taken when making the anchorages correctly to avoid leaks under the roof.

Mobile photovoltaic structures

The amount of energy produced by the photovoltaic panels is conditioned by the incidence of solar irradiation. Ideally, the module should always be oriented according to the position of the sun. For this purpose, solar trackers are used that move the panels to follow the position of the sun.

This type of structure is more common in large installations that aim to maximize energy production as much as possible. However, there are a number of associated problems, especially in terms of maintenance.

The solar tracker is a moving part with a motor that will move the panels as needed. But this type of mechanism usually requires continuous maintenance because if for some reason it stops working, the energy loss is usually much higher than if the panel were fixed at the most optimal inclination.

Materials of photovoltaic structures

The materials used to manufacture the structures for photovoltaic modules vary from manufacturer to manufacturer, and their choice varies depending on the site where they will be installed and the conditions in which they will be located. However, despite these factors, currently the most common material for structures is aluminum, although iron and stainless steel can also be found.

Aluminum photovoltaic structures

Aluminum is the most widely used material in photovoltaic installations because of its great advantages such as easy machinability, light weight and high strength.

The module structures  by Techno Sun from serie TS are all made of anodized aluminum to prevent oxidation, and with the same alloy used to manufacture the windows, making them resistant to the outdoors and to inclement weather. 

Iron photovoltaic structures

Iron is a type of material used for very large installations where the panels must withstand strong winds.

This material has some disadvantages, such as the great weight that the structure can carry, so it would only be suitable for installation on the ground and the need to galvanize each piece. The iron must have been galvanized with a minimum thickness of 100 microns after cutting and welding to avoid corrosion.

Stainless steel photovoltaic structures

Although stainless steel is highly resistant to inclement weather, its main disadvantage is its high price and the difficulty in welding, which can only be done by experienced specialists.

In addition, if the solar module frame is made of aluminum, contact between the two materials must be avoided by using some type of insulator, since together they produce a high level of galvanic corrosion.