Designing a photovoltaic system means responding to customer needs, respecting the reference standards and creating the best possible technical solution.
Technical area and plant design.
When we talk about building a photovoltaic system, we refer to the technical area, and everything generally starts with the customer's request for sizing according to his consumption.
We usually carry out an inspection at the customer's premises and, if possible, also on the roof, to understand how it is set up, studying any critical issues, locating the premises with the electrical panels and the delivery cabin.
When you carry out an inspection on a roof, you already have an idea of what the photovoltaic system will be like and the problems that you will have to face.
When, on the other hand, it is not possible to go to the roof at first, we proceed with a request to the customer for technical documents on the building and photographs of the roof.
Sometimes it can also happen that the customer does not have the DWG drawings of the building or photographs of the roof, so in a preliminary phase the technical team relies on the Google earth software.
Google earth doesn't have absolute accuracy, but it provides a good starting point for creating a floor plan with a certain degree of accuracy compared to reality.
Project phases and types of roofing.
In a more advanced phase of the study, after the due site inspections, we are going to render the executive planimetry.
In a photovoltaic design on industrial companies we find different types of roofing.
The most common are:
> Double pitched roofs.
> Cup-shaped roofs.
> Shed roofs.
> The barrel roofs.
> Flat roofs.
Each of these types has a different arrangement of the photovoltaic modules and the substructure for fixing.
Currently, for the fastening of the photovoltaic modules, we at Inveco use certified aluminum bars that are riveted to the roof (corrugated sheet, sandwich panel) on which the clamps that form the anchorage of the photovoltaic module to the bars are screwed.
If the roof does not allow the use of fastening with riveted bars, such as for example a flat slab roof, the fastening of the photovoltaic modules takes place through the use of heavy concrete elements (photovoltaic ballasts) resting on the roof which, with their weight , stabilize and contrast the action of atmospheric agents on the photovoltaic modules.
The design of photovoltaic systems must take into account all those problems that can interfere with the correct functioning of the photovoltaic modules and with the possible use of the roof by third parties, such as the fire brigade.
Industrial roofing often comes with various elements that can limit the correct functioning of the photovoltaic system such as:
> Smoke and heat evacuators (EFC).
> Elements for air recirculation and conditioning.
The shadows produced by these elements during the time of day and the change they have during the year are then studied, especially in the winter months, which are more problematic due to the lower height of the sun on the horizon and consequently for the lower production of energy .
Regulations in the study of the photovoltaic system.
Of no less importance are the minimum distances that the photovoltaic system and all the related devices must respect according to the legislation from the elements that can come into contact with flames deriving from fires (Fire Brigade legislation).
In the study of the photovoltaic system, the technical area takes care, already from the stage of arranging the layout of the modules, of the subdivision of the strings or of the modules connected in series to each other.
Each inverter, in fact, is divided into a part of the system based on the power of the inverter itself, and is equipped with a certain number of inputs through which all the photovoltaic modules that will belong to that specific inverter are divided.
By doing so, the fitter and the electrician will have a layout with the physical and electrical subdivision of the system.
Also, no less important, is the design of the electrical lines of the system with the paths of the cable trays on the roof, the descent from the roof and the electrical connection works.
In conclusion, designing a photovoltaic system means responding to customer needs by respecting the reference standards, thus creating the best possible technical solution.
Refinement and accuracy by Eng. Giuseppe Gallo, INVECO GROUP technical office.