| Along with the booming development of the photovoltaic(PV) industry, the later maintenance of PV power station and the improvement of PV power generation efficiency have gradually become the focus of attention. Under the condition of blown sand in high altitude desert areas, dust accumulation on the surface of the solar panel has become one of the most affecting factors which influences PV power station steady and high-efficiency running. Cleaning the dust has become one of main job for the later maintenance of PV power station in desert areas. According to the characteristics of dust composition, morphology and particle size, dust adhesion model is proposed to explain the formation of dust accumulation one solar panel surface. In this article, Base on the research of relationship between dust and PV power generation efficiency we have done physical erase experiment to solve the problem of dust accumulation. We have made a dust cleaning machine for this test.Composition of dust on the PV solar panels’ surface and fine sand on the ground surface are tested in desert area:Geermu city and Gonghe County, they are close to each other. Through microscopic observation, dust particles morphology is spherical. Particles diameter of them belong to micron-sized particles(dust D=0.356~126.192 μm;fine sand D=0.283~158.866 μm). It can be seen that dust on solar panel surface may originate from the ground surface. The photovoltaic power data, loading current, voltage are measured to establish the relationship between dust and PV power generating capacity. Density of dust on solar panel surface is 1~8g/m2, and the efficiency of power generation will generally reduced by 5%~25%; with increased of the amount of dust, PV power generating efficiency decrease obviously, like an exponential way.Analyze the dust adhesion theory by the view of energy. According to the macro-molecule interaction theory conclude the model of dust particles adhesion without considering the contact deformation; obtain the force parameters by measuring the composition and the size structure of the dust particles; analyze the Van der Waals force, electrostatic force and gravity which the dust particles subjected, and give the variation of each forces caused by the change of the dust parameters.The adhesion force between the dust particle and solar panel surface, ranging from 10-10 N to 10-8N, is positively correlated with the dust particle radius. It is summarized that when the dust particle radius is small, the main adhesive force between particles and panels is Van der Waals force, while gravity could play a leading role when the dust particle radius is bigger.Base on the characteristic of dust, dust adhesion force and the conditions of desert area, dust cleaning experiment is conducted mechanical erase with small amount of water. By changing some critical erase parameters, for example: erase forces, erase velocities, erase methods, erase times, we conclude that: in a certain range, there is a positive correlation between erase force and cleaning result. erase velocity have little impact on cleaning result. Under the given erase force(0-250N), secondary erase and third time erase have obvious cleaning result, but it not need additional erase. As dirt is still exists after water cleaning, analyzing the composition and characteristics of groundwater which is used in cleaning dust. Combine with characteristics of dust, exploring the cleaning scenarios by adding chemistry reagents. It can be achieve a better cleaning effect by adding anionic surfa- ctant in the acidic water with reasonable proportion.The study on mechanism of dust particle adhesion and cleaning from solar panel surface provide theoretical basis for the later maintenance of PV power station in high altitude desert area, and then increase the PV power generation efficiency. |
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