The photo is sourced from hovall.com
The researchers compared three photovoltaic modules with different front glass thickness (2.8 mm, 3.2 mm and 4.2 mm respectively), which were hit with icy globules of 45 mm in diameter. Eventually, the module with 2.8 mm glass lost 21.8% of its capacity, the module with 3.2 mm glass – 11.7% of capacity, while for the module with 4 mm glass such capacity decrease made only 0.8%. Moreover, when experimenting with the globules of 55 mm in diameter, the decrease of capacity for the module with the thickest glass made only 1.1%.
Such difference is underpinned by the depth of fractures, which may put the entire areas of cells out of the operation. Fractures on the modules with 2.8 mm and 3.2 mm glasses could be observed with the unaided eye; but the modules with 4 mm glass demonstrated only micro-fractures, which could be identified only with special optics. This factor affected the grid-leak resistance in the conditions of high humidity: for the module with the thinnest glass the ability to resist humidity and wetness decreased by 55.3%, for the module with the medium-thick glass – by 46.8%, and for the module with the thickest glass – by 27.2%.
The outcomes of the research may affect the risk assessment for solar generation in the regions with frequent hail precipitation. However, this is not the only risk for the operators of photovoltaic panels. Thus, in the deserts one of the risks is sand getting onto the surface of solar cells. Contactless cleaning proposed by the researchers of the Massachusetts Institute of Technology (MIT) may help to cope with this problem. It is based on the electrostatic repulsion principle. The conductor placed above the solar panel attracts the sand particles, while as the opposite charge of the generator’s surface repels the particles, which go up to the air and precipitate on the conductor. This method is safer than cleaning with a dry brush that may cause damages of the panel’s surface, and it is more economical than using the distilled water that is not always accessible in arid regions.
