For PV systems on roofs with less than 30 degrees roof slope, the self-cleaning of the modules through rain and snow is not sufficient. Settings on the modules of dirt is deposited which, if it is not removed, image burning into the module, and only by the use of chemicals can be removed.
Most manufacturers say unequivocally that. cleaning with lime-water and a soft brush No cleaning agent is used, it would provide for residues on the surface and could, for example, the rubber seals may deteriorate. Even the ingredients of normal tap water, such as dissolved salts and lime would leave after drying streaks and spots on the modules.
A water purification system supplies our cleaning with demineralized water. High pressure cleaners are generally not recommended because the silicon film only one micron (one millionth of a meter) thick, and it can break when using an HD cleaner.
To stall - or fattening houses developed by ammonia and Metangasen mixed with feed dust and dew, a rubber-like coating that is not washed by rain or snow. Systems on pig stalls tend to develop mosses and lichens. Right here is the context for modules with regular cleaning is very important.
If the reduction in yield is greater than the expected return, must - in the system is intact - a cleaning done. It should be noted that the cumulative shortfall in output. That is, the reduction in yield of the first given year continues in the second year. Plus the reduction in yield of the second year, and so on.
First, the question of whether cleaning is necessary to be answered only if the proceeds are constantly monitored and compared. However, the comparison of annual income brings little. The comparison with an adjacent area with similar design (Module, inverter, orientation, tilt) may be helpful.
many cases, the opinion is held that one should clean the spring in order to optimally capture the good yields of summer. But are opposed to the cleaning effect of winter with lots of rain and possibly snow. Light dirt is rinsed off. It is better to consider the causes of pollution is. If the system is mounted on a barn roof that provides air with dust, fumes and ammonia constantly for new protection.
Are trees and grain fields nearby, is the largest of dirt in their heyday. A hall for grain drying / storage after harvest and caused the biggest stir. There is a wood burning in the wind direction, the chimney in winter can provide for carbon deposits. We recommend cleaning shortly after the main cause of the pollution. The date is chosen often too late. Contaminants adhere to the already three to five years on the modules are stubborn, caked and baked by the sun. There are already algae, mosses and lichens grow. Accordingly difficult is the long soaking and cleaning with aggressive brushing. Initial cleaning should therefore already in second place in the third year at the latest.
We use to clean the PV modules only demineralized water. So-called pure water. Ultrapure water contains as opposed to management or rainwater as good as any foreign substances, but over the property charged ions and thus has a real resolution.
ultrapure water flows over a dirty surface, then remove all existing fouling. After a thorough rinsing and drying is a completely streak-free surface. This natural form of soil removal is not only absolutely gentle and effective for the modules, but also the most efficient shape for the environment.
