The performance of photovoltaic panels also depends, to a great extent, on their cleanliness and good maintenance status, so it will be very important to take care of their cleaning.
Dirt is deposited on the surface of the panel making it difficult to capture the electromagnetic radiation with the consequent reduction in the production of electricity.
The losses produced by the dirt deposited in the collectors vary between 10% and 15% according to various studies although an agreement has not been reached between the researchers.
For this reason, within the different preventive maintenance programs of the plant , it will be necessary to plan the cleaning tasks necessary to maintain the surfaces of the panels in perfect condition, maximizing the production of electricity and reducing the period of amortization of the investment.
The elements deposited on the surface of the collectors are very heterogeneous and will depend to a great extent on the location of the plant, the inclination of the panels and the climatic conditions of the area .
In general, the waste will be related to pollen from nearby plants and trees, dust generated by urban areas or transport routes, leaves and other plant residues, salt deposits in areas near the sea and, of course, bird droppings. .
A classification can be made of the different cleaning methods that can be used characterizing them according to different parameters. We will distinguish between methods with friction or without it, cleaning with water or dry, and manual or mechanized. Attending these classes we can distinguish several modalities:
- Cleaning with pole and water: It is a system of cleaning by friction, manual and with water. It consists of a pole of polyester and carbon fiber of variable length with a brush of light and soft fibers at its end, equipped with a system of supplying pressurized water with particle filter and decalcifier to ensure the suitability of cleaning.
- Cleaning with water pressure: Consists of a truck with a water tank of not less than 2,000 liters equipped with motorcycle pump group. The guiding of the pressure guns can be done by an operator or can be controlled by an automatic system. Depending on the configuration of the panels, it may be necessary to attach a lifting platform to access the entire surface to be cleaned. We would classify it as a frictionless method, with mechanized water. Before choosing a system by pressurized water it will be necessary to consult with the manufacturer of the panel since in some cases this method of cleaning is discouraged, and may even lose the guarantee if it is used.
- Cleaning with steam: A variant of the previous system consists of using steam to clean the solar collectors. In addition, the truck, the tank and the filtering and decalcification equipment must have a heating device to obtain the steam and a bell, usually textile or plastic, to concentrate the steam in the cleaning area.
- Cleaning by self-propelled roller: The cleaning is carried out by means of large rollers formed by soft cleaning bristles mounted on an extendable arm coupled to a motorized vehicle, equipped with a water tank, pumping equipment, filtering and water softener. The process resembles automatic vehicle cleaning machines; first a soapy water spray is produced, the cleaning with the rollers and, finally, rinsing with treated water. It will be a method of cleaning by friction, with water and machining.
- Automatic mechanized cleaning: Consists of systems coupled to the frames or structures that support the photovoltaic panels and that by means of automatic cleaning rollers or periodic spray systems clean the surfaces without the need for personnel intervention.
- Cleaning by means of robots: In systems with difficult access, such as those placed on the roofs of buildings or industrial buildings, small cleaning robots are used that automatically cover the collection surface by cleaning with different technologies. They are not suitable for panels with an inclination angle greater than 45 °.
The cleaning procedures are multiple and varied. The important thing will be to find the most suitable for the concrete installation . Ultimately water, suede and soap.