The importance of regular cleaning of solar panels and the most effective way to clean them    


Photovoltaic solar energy has been seen as a sustainable renewable alternative due to the over-extraction and use of fossil fuels. But in the process of installing the sun, many people overlook the importance of clean solar panels. Others argue that, as long as the Angle of installation is large enough, not cleaning the panels will not affect their efficiency1. This article will discuss the importance of clean solar energy from two experiments.

What are the effects of dirty solar energy for a long time and the influence of dirty solar panels on their work.

In the first experiment, we collected data on dust accumulation and work efficiency of solar panels at different installation angles

2 the experimenters carried out detailed experiments on the influence of dust on the solar panel collector. Seven solar panels were used in the experiment. Six of them were divided into three groups, two in each group, and were subjected to various inclinations of 0 °, 30 ° and 60 °. The seventh collector is inclined vertically by 90 °. In each group, one collector is regularly cleaned while the other is not disturbed. The solar energy absorbed by the unclean plate is calculated and compared with the cleaned plate. One observation indicates that the dust collection volume between April and June is about 2.5 g / m2 / day. Sayig et al. 3. Also studied the effect of long-term dust accumulation on solar glass panels. After exposure for about 38 days, the light transmittance of the panel decreased by 64% to 17% from the inclination angle of 0 ° to 60 ° respectively. In addition, after 3 days of dust accumulation, the useful energy gain of the horizontal precipitator was reduced by 30%. The following figure shows the effect of tilt angle on the decrease of solar transmittance

Through another experimental study on dust accumulation effect of solar panels, the working current and voltage of solar panels without cleaning for a long time are obviously decreased4. Laboratory experiments were conducted to study the effect of dust accumulation on the surface of solar panels
(figure 1)
The above figure 1 shows that voltage characteristics of the solar panel under observation.At the beginning of the experiment, researchers collected data on the transparent surface of the solar panel. The maximum voltage was 18.86 volts and the maximum light intensity was 21500 W/m2. The following table shows the data collected during experiments using transparent solar panels. The energy produced by the solar panel is given by P=VI. On transparent surfaces, solar panels achieve maximum yield.But as the stain layer begins to accumulate on the surface of the solar panel, the area under the curve becomes smaller and smaller. Finally, The amount of energy produced is significantly less and less5. Figure 2 shows the data of the dusty panel.
(figure 2)

Figure 2 show us that due to dust accumulation there is a slight reduction in panel’s voltage and hence power. The maximum voltage obtained in this case is 18.32 volts at maximum lux of 21500 W/m2. The table given below illustrate the data for dusty panel collected during experiment. 

Accrual of dirt on exterior of PV panel also leads to a decline of efficiency of the solar PV. Efficiency of PV array is observed on the basis of voltage variation of clear and dusty panel.  

                     N= VP X IP /PS X A

Vp and Ip are the voltage and current of the solar panel, Ps is the power generation, and A is the surface area of the solar panel. According to the experimental data collected in the test process, the voltage of clean plate and dust plate are compared. As can be seen from the following figure, the voltage of the solar panel decreases significantly due to the long-term accumulation of dust on the surface of the solar panel. In the worst case, a decrease in panel voltage can result in a 40-50% decrease in panel efficiency. This can lead to huge energy conversion losses. The following table shows the data collected by cleaning the dusty plate experiment. When the maximum light intensity is E, the effect of dust on the luminescence efficiency is about 71%, and the luminescence efficiency is improved by 90% on this basis.

(figure 3)
The prototype can be used to clean the surface of solar panels, increasing their efficiency by 18%. A 40-watt (20-volt) solar panel was used in the experiment, with a maximum output of 36 watts, and most commercially available panels have an efficiency of 18-16%. If the power of the solar panel goes down from 20 watts to 18 watts the power output of the solar panel goes down by about 10% In conclusion.As can be seen from the above two experiments. No matter in what kind of installation Angle, long-term dirty solar panels, its efficiency will have a significant decline. Different cleaning methods also have different effects on solar panels. For ordinary people, there are two ways to clean solar energy. The first method is to clean it directly with cloth, and the second way is to use water and brush. such as the one shown below. This picture compares a solar panel cleaned with water and a brush to a panel cleaned with a cloth. The blue part is the cloth cleaning part, and the green part is the water and brush cleaning part. It was clear that the panels were cleaner after being cleaned with a brush, as if they were new.6
Red-Un cleaned, blue- cleaned with cloth, green- cleaned with water and brush. )

As shown in the picture above. According to one experiment, on a cleaned solar panel. The reduced amount of dust and the efficiency of sunlight conversion are obvious hints.Clean the panels regularly with water and a brush to remove all the dust more quickly. Get the solar panels back to about 20 percent of normal efficiency.

Reference list 1Denholm, E. Drury, R. Margolis, M. Mehos Solar energy: the largest energy resource F.P. Sioshansi (Ed.), Generating electricity in a carbon-constrained world, Academic Press, California (2010), pp. 271-302 2A.M. Sayigh Effect of dust on flat plate collectors F. de Winter, M. Cox (Eds.), Sun: mankind’s future source of energy; proceedings of the international solar energy congress, New Delhi, vol. 2, Pergamon Press, NY (1978), pp. 960-964 3A.M. Sayigh, S. Al-Jandal, H. Ahmed Dust effect on solar flat surfaces devices in Kuwai C. Furlan, N.A. Mancini, A.A.M. Sayigh, B.O. Seraphin (Eds.), Proceedings of the workshop on the physics of non-conventional energy sources and materials science for energy, ICTP, Triest, Italy, World Scientific, September 2–20, 1985 (1985), pp. 353-367 4Akbar and T.Ahmad Enhance and Maintain. Efficiency of Solar Panel using Auto Cleaning System Vol. 6, Issue 05, PP. 159-163, May 2019 5Jaiganesh , K. Bharath Simha Reddy, B.K.D. Shobhitha, etc. Enhancing the effificiency of rooftop solar photovoltaic panel with simple cleaning mechanism: Proceedings 51 (2022) 411–415 6Jaiganesh , K. Bharath Simha Reddy, B.K.D. Shobhitha, etc. Enhancing the effificiency of rooftop solar photovoltaic panel with simple cleaning mechanism: Proceedings 51 (2022) 411–415
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