This is an excerpt from EERE Network News, a weekly electronic newsletter.

April 13, 2011

Russian Scientists Team with NREL on Innovative Weathering System

How can you test the effects of sun damage on a product without overheating the product being tested? A unique collaboration between DOE's National Renewable Energy Laboratory (NREL), the Russian Institute of Laser Optical Technology, and Atlas Material Testing Technology of Chicago has a solution. They've developed the Ultra-Accelerated Weathering System (UAWS), which simulates the harmful effects of decades of sun damage on outdoor products like coatings and paints in just a matter of months. Sun damage is a particularly difficult weather effect to test because it requires a process that amplifies the effects of the sun without overheating the product being tested. Additionally, the majority of sun damage is caused by ultraviolet (UV) rays, not the visible and near-infrared rays that we associate with the sun's heat.

The UAWS adjusts for these issues by using an array of 29 curved high-tech mirrors to focus UV wavelengths on a target area. Alternating high- and low-refractive coatings on the surface of the mirrors, 96 layers of coatings in all, ensures that UV wavelengths are primarily reflected toward a chamber that holds the products being tested. It's a process called "spectral splitting"—because the mirrors block the reflection of visible spectra and near-infrared wavelengths, the system dramatically reduces overheating. These characteristics make the UAWS perfect for accurately simulating sunlight damage 12 times faster than was previously possible—both for familiar outdoor products like roofing shingles and for cutting-edge materials like SkyFuel's ReflecTech mirror coating, another NREL invention that could greatly reduce the delivered cost of concentrating solar power. See the Energy Blog post.