L R AS Published on Saturday 26 January 2019 - n° 261 - Categories:panels
Improvements made to the panels: anti-reflection, anti-dirt, cleaning
Developed around 2013, and after their potential for improved performance and sustainability has been identified, anti-reflective coatings cover the panels. By trapping light and transmitting it to the cell, anti-reflective coatings have the effect of increasing the light output of the cell.
2 to 3% the output power. This gives anti-reflective coated glass a market share of 90%. The only challenge for manufacturers is to increase the service life (in the order of 15 years) and durability of the panels. Durability is the maintenance of the material characteristics at an acceptable level. after exposure to aggressive mechanical or environmental conditions.
Today, coating suppliers are looking at ways to reduce the cost of losses due to soiling. In 2017, the Dutch chemist DSM launched its first anti-fouling coating to prevent the accumulation of dust on the glass surface. The lower price of the panels proportionally increases the cost of cleaning operations.
A smooth surface, without any bumps or craters where dust could accumulate, has very different characteristics from the characteristics of anti-reflective lenses, which must have a surface roughness that allows them to trap light. Combining the two opposite aspects is another challenge.
The British company Opus Materials believes that both characteristics can be combined with silica nanoparticles, which improve the properties of the coating. They are a source of roughness and a repellent capacity. In this way, the two opposing characteristics are combined. For its part, DSM claims that its anti-fouling coating has the same anti-reflective properties as its other product, and that the coating provides a similar 3% increase in panel output measured in flash test compared to uncoated panels. In addition, anti-fouling panels could maintain optimum performance for longer periods, resulting in an additional average 1% increase in production over time. Opus also indicates that its tests indicate that the Solar Sharc coating will be able to increase production by around 4%.
Cleaning: Antifouling coatings promise to reduce the need for cleaning, none have promised to eliminate it completely. Convection cleaning could throw off abrasive particles. Cleaning with water may dissolve the coating. One study has shown that coatings have difficulty remaining effective and stable even for ten years, even if suppliers make improvements.
DSM has entrusted the next generation of glass coating to cleaning equipment suppliers and that its coating has remained stable after 1,000 cleaning cycles, the equivalent of 20 years of bi-monthly cleaning.
Installation of anti-reflective and dirt-repellent coating on panels in productionBoth suppliers claim to be able to install the coatings because the product can be applied at room temperature and without drying time. The processing time of a panel can be reduced to one or two seconds and dries in less than one minute at a temperature of 20°C. The gain in energy production is attractive because these old generation panels have a high buy-back rate.
PV Magazine of 26 January
