With the growth of global population and the rapid development of economy and society, the demand for energy is increasing day by day. Although the traditional fossil energy is still occupying the dominant position of the global energy structure, but the energy in the process of consumption, inevitably will release a variety of pollutants and greenhouse gases, carbon dioxide to global ecological environment protection and climate change, therefore, all countries in the world are currently trying to develop new energy technology, Such as wind power, solar energy, nuclear energy, geothermal energy, biomass energy and so on.
China has a vast territory and abundant resources, rich in land resources and light and heat resources. In recent years, the proportion of new energy generation in the national energy structure is also increasing year by year. Take solar energy for example, whether it is the large-scale photovoltaic power generation base, or the small photovoltaic installed on the top of rural houses and in the yard in the new rural construction, it is more and more common in China. It not only meets a certain amount of the country's energy demand, but also promotes the improvement of the environment in the vast area.
However, photovoltaic power generation is affected by the physical principle of energy conversion and must be based on receiving solar radiation in a large area. Therefore, it is difficult to achieve a significant breakthrough in the light energy conversion efficiency of existing solar panels in the short term. On the one hand, flat terrain conditions are required; On the other hand, solar panels need to cover as much ground as possible. In this context, it is natural for us to turn our eyes to desert areas, because there are almost no human activities and arable land there, and the area is vast, the terrain is small, and the light and heat resources are relatively rich, which has excellent conditions for solar energy development.
In recent years, our country in xinjiang, qinghai, Inner Mongolia provinces (area) development and construction of a large number of large scale photovoltaic power generation base, the other in the west of jilin, the qinghai-tibet plateau and the sichuan basin area, also in actively plot construction corresponding photovoltaic base, the base of a lot is located in the arid areas, gobi desert or comparison. Some people can not help but ask, in the dry desert and surrounding areas to build photovoltaic power base, where the wind is generally large, the solar panels are easy to fall on the dust, if the dust is not cleaned up in time, is bound to seriously reduce the efficiency of solar panels, how do we do?
At present, the global photovoltaic power generation base or household small-scale solar panels, will be affected by dust, whether in the desert or plain, if the dust on the solar panel is not cleaned, on average for a month, its power efficiency will be reduced by about 30%. Based on the global installed solar capacity of 500 GIGawatts by 2020, the economic loss caused by reduced efficiency of power generation due to dust could reach as much as $5 billion a year. By 2030, global solar capacity is expected to grow to 1,400 GIGawatts, a loss of $13 billion.
For a long time, in order to solve this problem, the commonly used method is basically the use of water washing, the advanced point is the use of pressurized water jet and spray, the low-level approach is to scrub manually. Both low-level and high-level methods require a lot of water. The amount of pure water used to clean solar panels alone amounts to more than 37 billion liters a year, equivalent to the annual water consumption of 2 million people, based on the current global solar power generation. Of course, the above traditional way is quite difficult and costly. The labor cost of manual washing, the electricity consumed by mechanical washing and the maintenance cost of equipment need to be calculated into the comprehensive cost of the power plant.
And whatever the water washing method, is impossible to keep the solar panels of the cleaning effect, there will be some blind spots and blind Angle, some panels also wash clean enough above, in this way, will inevitably produce "hot spot effect", which is not be cleaning parts, panels will most likely by generating unit into a power unit, On the one hand, it will reduce the overall efficiency of power generation, on the other hand, it will also cause heating, causing accelerated aging of the panels, and even fire.
At the same time, many photovoltaic power plants are built in arid or even desert areas, where water resources are already scarce, and the use of water washing itself is a waste of resources. Therefore, the research on new cleaning methods of solar panels has become an important field of competition in many countries.
One solution that has been proven to work is to add a special, very thin coating to the solar panels to protect them from dust without affecting the sun's rays.
The specific principle is the use of electrostatic repulsion. Applying an electric current or an appropriate voltage range through an electrode, such as a metal rod, so that the electrode passes just above the surface of the solar panel, causes the dust particles attached to the solar panel to become electrically charged (the silica particles in the dust attract tiny amounts of moisture in the air, thus allowing the dust particles to become electrically charged). An opposite charge is then applied to this thin coating film, which causes the panel's glass surface to strongly repel dust particles.
Dust rejection in this way relies on tiny amounts of electricity from the solar panels to power the electrodes, which consume far less power than the amount lost to dust cover.
When using this method of coating, it can effectively dust, sand, soot and even bird droppings are difficult to firmly adsorb on the solar panel, so that when it rains, it will effectively remove these coverings, equivalent to a self-cleaning function. If the area where the photovoltaic power generation base is located has scarce rainfall, it is possible to carry out manual or mechanical auxiliary cleaning regularly, which will reduce the water consumption and washing frequency much more than before, undoubtedly greatly reducing the operating cost.