With the increasing demand for energy in society, the problem of “energy security crisis” has become increasingly prominent, and the problem of “global warming” caused by traditional forms of energy utilization has also become increasingly apparent. As a new form of energy, renewable and clean energy has been paid more and more attention. Under the circumstances, solar energy attracts more and more people to use it, so how to use solar energy reasonably and efficiently is a major issue for us. This article will explain the influence of temperature, shading, dust, etc. on solar power generation, to explain the main reasons that affect the efficiency of solar power generation.
At present, photovoltaic power stations mostly use silicon-based solar cell modules, which are very sensitive to temperature. With the accumulation of dust on the surface of the modules, the thermal resistance of photovoltaic modules is increased, which becomes the insulation layer on the photovoltaic modules, affecting its heat dissipation. Studies show that the output power of solar cells decreases by about 0.5%, the temperature rises by 1°C. In addition, under long-term sunlight exposure, the temperature of the covered part is much higher than that of the uncovered part, resulting in dark spots that burn out when the temperature is too high. Under normal illumination, the covered part of the panel will change from a power generation unit to a power consumption unit, and the covered photovoltaic cell will turn into a load resistance that does not generate power, consuming the power generated by the connected batteries, this is the hot spot effect. This process will aggravate the aging of the panel, reduce output, serious will cause module burn.
Dust adheres to the surface of the battery modules, which will block, absorb and reflect light, the most important of which is the blocking of light. The reflection, absorption and shading of dust particles on light affect the absorption of light by photovoltaic panels, thereby affecting the efficiency of photovoltaic power generation. The study pointed out that dust settling on the surface of the panel assembly will first reduce the transmittance of the panel surface; Secondly, the incident angle of some light will change, resulting in uneven transmission of light in the glass cover plate. Studies have shown that under the same conditions, the output power of clean panel components is at least 5% higher than that of fouled modules, and the higher the amount of fouling, the greater the decline in module output performance.
The surface of photovoltaic panel is mostly made of glass, and the main components of glass are silica and limestone. When wet acidic or alkaline dust is attached to the surface of glass plate, the components of glass cover plate can react with acid or alkali. As the glass in acidic or alkaline environment time growth, glass surface will slowly eroded, thus formed in the surface of bumpy phenomenon leads to the formation of a light in the flat surface diffuse, spread uniformity is damaged in the glass, photovoltaic modules cover the more rough, the smaller the refraction of light energy, actually reach the surface of the photovoltaic battery energy is reduced. As a result, the power generation of photovoltaic cells decreases. And rough, sticky surfaces with sticky residues tend to accumulate dust more easily than smoother surfaces. What’s more, dust will also absorb dust by itself, once the initial dust exists, it will lead to more dust accumulation, accelerating the decay of photovoltaic cell power generation.
IV. Dust Cleaning
The glass surface of photovoltaic modules placed outdoors will capture and accumulate dust particles, forming a dust cover that blocks light from entering the cells. Gravity, van-der-Waals forces, and electrostatic field forces all contribute to dust accumulation. Dust particles not only interact strongly with the photovoltaic glass surface, but also interact with each other. To clean the dust is to remove the dust from the surface of the panel. To remove the dust on the surface of the battery board, it is necessary to overcome the adhesion between the dust and the battery board. The dust on the battery plate has a certain thickness. When cleaning it, you can apply a parallel load to it, a load at a certain angle (or perpendicular) to the battery plate, or apply a rotational torque to the dust layer, to destroy the dust and the battery. Destroy the adhesion between dust and panel, and then remove dust.
In short, atmospheric dust is one of the key factors affecting the efficiency of solar power generation, dust pollution can significantly reduce the output of photovoltaic power plants, estimated to be at least 5% per year. Of course, this is also why the use of photovoltaic cleaning machine is important.
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