Among the maintenance processes of photovoltaic modules, cleaning the panels is an essential item. This is because the accumulation of dirt can reduce the energy efficiency of a panel by up to 25%, according to the NREL (National Renewable Energy Laboratory).
Solar energy companies report losses of up to 30% in cases where the user never cleaned the panels – this is in extreme situations, in places where there is little rainfall. To assist with this maintenance item, and ensure the efficiency of solar panels, there are several companies in the Brazilian photovoltaic market that offer products and services for cleaning photovoltaic modules.
But after all, what do solar panel manufacturers recommend? What products can be used? When should modules be cleaned? Can you use solvent? Is the use of a pressure machine permitted?
These questions are asked daily in WhatsApp groups and Telegram. To clarify these doubts, the Canal Solar consulted cleaning manuals from the main manufacturers and listened to experts from the national and international photovoltaic market.
It's all in the panel manual
All equipment has a manual that aims to guide and inform about its correct application, operation and maintenance. Following their instructions is a guarantee of ensuring the product works properly.
Therefore, representatives of manufacturers of painéis solares highlight that when cleaning a panel it is essential to read it since, although they have similar recommendations, each company has its own guidelines for cleaning this equipment.
According to the manuals of the main manufacturers, the most important factors when cleaning solar panels are the cleaning process intervals, the products and equipment that can be used and what precautions should be taken during the cleaning process.
When should cleaning be done?
Manuals from several manufacturers, including JA Solar, LONGi, Jinko, Risen and Trina, recommend that panels should be cleaned annually, but state that in places with a lot of dust and pollution, cleaning is recommended every six months.
Already BYD Instructions in its manual that cleaning must be carried out every three months and that this interval can be reduced depending on the environment in which the products are installed. According to the manufacturer, the most suitable time is early in the morning or late afternoon, when the modules have a lower temperature on their surface. This will avoid possible damage caused to the glass due to thermal shock, that is, the contact of cold water with the high temperature present on the surface of the module.
Another important point highlighted by the manuals is that before the cleaning process, the modules must be inspected for cracks, damage and loose connections. Furthermore, they state that the back surface of the module does not need to be cleaned, but if necessary, the use of any sharp designs that could damage the module should be avoided.
See also: Solar energy and sustainability: what is their relationship?
What products to use?
A common question among professionals is about which products should be used in the panel cleaning process. According to the Risen manual, soft dry or damp cloths and sponges can be used.
However, corrosive solvents and hard objects should not be used. JA Solar emphasizes in its manual that the use of metal tools, such as blades, knives, steel wool and other abrasive materials for cleaning is not permitted.
In accordance with the JA Solar and Risen Energy manuals, the Canadian and Jinko They state, in their manuals, that it is not recommended to use water with a high mineral content or corrosive cleaning solutions that contain hydrofluoric acid and alkaline substances, acetone or industrial alcohol.
If a panel is damaged due to the use of a cleaning product not recommended by the manufacturer, Gustavo Tegon, Sales Director at Canadian, gave an example of the damage that can occur. “Using a product not recommended by the manufacturer may damage or even completely remove the anti-reflective coating on the glass, causing stains on it. The result of all this is the loss of energy generation and also the product warranty,” he stated.
Risen also highlights in its manual that cold water should not be used to clean the module when the temperature is high during the day, otherwise there will be a risk of damage to the panel.
Is the use of a water pressure machine permitted?
When it comes to using cleaning machines, not all manufacturers have the same recommendations. While Risen and ZNShine Solar recommend that the water pressure on the glass surface of the module should not exceed 700 kPa (7 bar), JA Solar emphasizes that the cleaning water pressure should be less than 690 kPa (6,89 bar).
According to the Canadian manual, for the use of machines, the maximum recommended water pressure is 4.000 kPa (40 bar). And in BYD manual, the manufacturer informs that the water pressure must be regulated up to 5.000 kPa (50 bar). According to BYD, this limitation aims to prevent damage to the glass surface and loss of light transparency.
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Who can carry out the cleaning?
In their manuals, manufacturers advise that panels should be cleaned by a trained team and that workers should wear PPE (personal protective equipment). In Brazil, there are several companies that already offer installation and/or equipment, and they also guarantee a specialized maintenance service, for a certain cost.
For example, in homes with a single floor, the process ends up requiring less equipment, just a ladder to facilitate access to the panels, a squeegee with a damp cloth – in some cases, a cable extender can help – and a hose with a water gun. In taller and more complex installations, it is essential to hire specialized professionals with appropriate safety equipment.
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Answers of 16
Good morning, to clean the photovoltaic panels, can I use a jet wash (wap) and a hair broom?
It is best not to use a car wash. The pressure is too high and can cause micro-cracks. Wash with a jet of moderate pressure – garden hose. Use a new “squeegee” with foam bristles. Then wipe it with a clean damp cloth and finally a dry cloth to dry it. It is not advisable to use liquid soap or glass cleaner. I have done this before and it did not turn out well. I had to clean it again.
Can we use a nylon brush to clean the modules?
Better not. It will remove the anti-reflective film often deposited by the manufacturer on top of the glass. See the item above for a suggestion.
Hello
Is the use of a nylon brush to clean the modules permitted by the manufacturers?
Good afternoon, is there any indication or need for maintenance or cleaning of the energy converters?
Good afternoon, who can I get a quote for this solar panel washing machine from?
I didn't mention the approximate amount of water used to clean, do you have an estimate?
Hello, Iza, how are you? The amount of water used for cleaning depends on the size of the plant, and also the type of dirt found in the modules (and how long this dirt has been in the modules).
Dear Evald, regarding the problem of birds sheltering under your photovoltaic panel: the efficiency of the solar-to-electric conversion of the photovoltaic panel decreases a lot… a lot indeed as the temperature increases. The movement of air on the underside is important for cooling. It is not a good idea to close the side opening with Styrofoam. If it is strictly necessary, I suggest you use a metal screen to prevent birds from entering the area below the panel… while maintaining the passage of air. It may seem like a joke, but in my city, we use small “statues” of birds of prey (eagles or hawks) near the panels. They keep the pigeons away.
A few months ago, after installing a solar power generation system in my home, several pigeons began to settle, especially in the late afternoon, under the solar panels, in the space between them and the roof. I can't keep them away. I'm thinking of sealing the side of the area occupied by the panels with Styrofoam or something similar to prevent the pigeons from settling under them, but this could compromise the system's operation.
In light of this, I ask for guidance on what I should do.
I saw some recommendations to turn off the system during cleaning.
Is there any recommendation in this regard?
Remembering that even if the inverters are turned off, the panels will still be generating energy…
Cleaning can be done with the system operating normally, if the operating manuals are followed, all components have IP protection
The panel cannot be washed very hot, and must be washed with a specific detergent, pure water causes stains, these stains reduce the penetration of sunlight.
Good morning, I know that you have to clean it with water without using any product. As for the temperature, it's complicated because it's a very hot day and it rains and the panels are hot and sensitive. They have glass on top to protect them from hail and everything else. How can they be sensitive to a damp cloth?
Excellent article, I'm from the area and I work in the field, I liked it