SOLAR MIRRORS : YEARS OF OUTDOOR EXPOSURE, A CHALLENGE

Already for some time now, we are confronted with the high prices we have to pay for energy and it is hard to predict what the future will bring. Besides these high prices we also need to avoid CO2 – emissions as much as we can and for this reason we also have to look for alternative ‘environmental’ friendly energy sources.
These are only 2 of the many reasons why there has been an increased interest in solar energy, not only based on photovoltaic cells but also based on reflection of sunlight (through mirrors) to 1 single point.

Also at FENZI environmental issues always have been very important so we already started some time ago to develop a paint system to be used on these solar mirrors which should have a very high outdoor durability as these power stations are located outside and even in most cases in desert areas.

The paint system must protect the mirror in different ways :

• The loss of energetic reflectivity should be less then 1 % after 20 years
• The loss of surface reflectivity due to corrosion should be less then 1 % after 20 years
• Resistance to abrasion (mainly sand) should be ok for a period of 20 years

The standard tests for mirrors are for sure not sufficient and these mirrors are ment for inside use so at FENZI we had to define new tests for these solar mirrors.
Among the standard tests we do the following tests to compare different paint systems and their outdoor durability :

• Multiple CASS, Salt Spray and Humidity test cycles
• Thermical cycle tests
• Sand abrasion tests according to ASTM D968
• UV resistance (QUV – test) up to 7500 h
• Weatherometer (WOM) up to 4500 h

With this project FENZI proves once again to be the leader and setting the trend in new developments in mirror paints.