With the rapid development of clean energy worldwide, photovoltaic power generation has become an important force in energy transformation. As the core of photovoltaic power generation systems, the power generation efficiency of photovoltaic modules directly affects the performance and economic benefits of the entire system. Photovoltaic modules are exposed to pollutants such as dust, bird droppings, and leaves outdoors for a long time, which can block sunlight and reduce the power generation efficiency of the modules. Therefore, regular cleaning of photovoltaic modules is particularly important. However, cleaning photovoltaic modules is not just a simple rinsing process, it requires certain technical requirements and operating standards.
1 The importance of cleaning photovoltaic modules
The surface of photovoltaic modules must be kept clean to ensure optimal light absorption and power generation efficiency. Research has shown that pollutants such as dust, sand, and bird droppings accumulated on the surface of components can seriously affect the power generation of photovoltaic systems. Especially in areas with high dust and sandstorms, the cleaning and maintenance of photovoltaic modules are particularly important.
1. Improve power generation efficiency
The pollutants on the surface of photovoltaic modules will reduce their absorption of sunlight and decrease their photoelectric conversion efficiency. According to relevant experimental data, the power generation of uncleaned photovoltaic modules may decrease by 5% to 20%, and under extreme conditions, this loss is even higher. Regular cleaning can effectively restore the power generation capacity of the photovoltaic system.
2. Extend the service life of components
Long term accumulation of pollutants not only affects the power generation efficiency of photovoltaic modules, but may also cause damage to module materials. Especially in areas with strong sandstorms, prolonged coverage of the component surface by sand and dust may cause minor wear on the glass surface of the component, accelerating material aging. Regular cleaning can prevent wear and extend the service life of components.
3. Improve economic efficiency
For large photovoltaic power plants, the input and output of cleaning photovoltaic modules are closely related. Regular cleaning can improve the overall power generation efficiency of the system, increase power generation revenue, and reduce economic losses caused by a decrease in power generation. At the same time, extending the service life of components can also save maintenance and replacement costs, thereby improving the overall economic benefits of the project.
2 Common sources of pollution in photovoltaic modules
The pollution sources of photovoltaic modules vary depending on factors such as geography, environment, and weather. The following are common sources of pollution:
Dust and sand particles
In dry and windy areas, dust and sand particles in the air are the most common sources of pollution for photovoltaic modules. Sand and dust not only cover the surface of components, blocking light exposure, but may also cause friction and scratches on the surface of components due to wind force.
Bird droppings
Bird droppings usually partially cover photovoltaic modules and have a serious impact on the panels, as they not only block light but also corrode the materials of the panels, causing local overheating and affecting overall power generation efficiency.
Leaves and other organic matter
It is common for organic matter such as leaves and insect corpses to accumulate on photovoltaic modules in photovoltaic power plants near forests or farmland. Although these impurities do not have a significant impact, if not cleaned up in a timely manner, they can easily create shadows on the surface of the components, affecting the power generation effect.
Industrial pollution
Photovoltaic modules near industrial areas may be affected by industrial pollution such as smoke and exhaust gas. These pollutants often have strong adhesion, are difficult to clean, and have a more significant impact on the components.
3 Basic principles for cleaning photovoltaic modules
The cleaning of photovoltaic modules needs to follow certain principles to ensure cleaning effectiveness while avoiding damage to the modules.
1. Safety first
When cleaning photovoltaic modules, it is necessary to ensure the safety of the operators. Especially when cleaning at high altitudes or in photovoltaic power plants, it is necessary to wear protective equipment and cut off the power supply to avoid the risk of electric shock.
2. Avoid using corrosive chemicals
The material on the surface of photovoltaic modules is usually specially treated glass, which has certain wear resistance and UV resistance functions. But if corrosive chemicals are used for cleaning, it may damage the surface of the components, resulting in a decrease in their protective performance. Therefore, it is recommended to use neutral cleaning agents or purified water for cleaning.
3. Moderate temperature to avoid sudden changes in temperature
When cleaning photovoltaic modules, the water temperature should be close to the surface temperature of the module, especially when cleaning under high temperature or direct sunlight. Avoid using cold water to suddenly wash hot photovoltaic panels, otherwise it may cause glass breakage.
4. Avoid scratching the surface of the components
When cleaning photovoltaic modules, soft cleaning tools such as soft cloth or sponge should be used, and hard brushes or metal tools should be avoided to avoid scratching the surface of the photovoltaic panel and affecting its light transmittance.
4 Cleaning methods for photovoltaic modules
According to the scale, environment, and pollution status of photovoltaic power plants, different cleaning methods can be selected:
Manual cleaning is the most common method for small and medium-sized photovoltaic systems or components with less severe pollution. During cleaning, the operator manually wipes with purified water, a soft brush, and a cloth. This method has a low cost and is suitable for some distributed photovoltaic projects or rooftop photovoltaic systems.
Mechanical cleaning is commonly used in large photovoltaic power plants, such as automatic cleaning robots or cleaning vehicles. The cleaning robot can autonomously walk on the surface of photovoltaic modules and remove surface pollutants by spraying water and using soft bristled brushes. This method is highly efficient and suitable for large-scale photovoltaic power plants, but the initial equipment investment cost is relatively high.
Drone cleaning is an emerging technology used in high-altitude or remote areas that are difficult to access. Drones carry cleaning devices that can quickly and safely spray and clean photovoltaic modules. It is suitable for high-altitude distributed photovoltaic projects or power stations with terrain limitations.
Some large photovoltaic power plants install fixed water flushing systems, which periodically activate water spray devices to perform simple flushing on photovoltaic modules. This method is more common in areas with abundant water resources, which can achieve automated cleaning and reduce manual operations.
5 Precautions for Cleaning Photovoltaic Modules
Cleaning time selection
The best time to clean photovoltaic modules is in the morning or evening, avoiding direct sunlight and high temperatures to prevent uneven heating and breakage of the glass. Meanwhile, rainy or strong wind weather should be avoided during the cleaning process to ensure safe operation.
Water quality requirements
Due to the sensitivity of the surface materials of photovoltaic modules, the water quality used for cleaning should be as clean as possible, avoiding the use of water sources containing high minerals or impurities. Otherwise, residual water stains or impurities may form scale on the surface of photovoltaic modules, affecting power generation efficiency.
Regular maintenance and cleaning
The cleaning frequency of photovoltaic modules should be reasonably arranged according to local environmental conditions and climate characteristics. In areas with more dust, it is recommended to clean once every quarter, while for areas with less pollution, cleaning once every six months to a year is sufficient.
Component inspection and repair
During cleaning, operators should also regularly inspect the photovoltaic modules for cracks, scratches, or aging. If any abnormalities are found, damaged components should be repaired or replaced in a timely manner to ensure the overall power generation capacity of the photovoltaic system.