ReflecTech® Mirror Film is commercially proven, ultra-lightweight and highly durable in outdoor solar energy applications.
| Specular Reflectance* | 94% |
|---|---|
| Solar-Weighted Hemispherical | |
| Reflectance** | >94% |
| Nominal Thickness | 0.0036” (3.6 mils, 0.09mm) |
| Tensile Strength | >50 lbs/in of width |
| *At 1.4° acceptance angle measured on D&S Specular Reflectometer **Integrated over air mass 1.5 solar spectrum |
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Research & Development on ReflecTech® Mirror Film at the National Renewable Energy Laboratory (NREL)
To test for weatherability, reflector samples are subjected to controlled conditions more extreme than experienced in actual outdoor environments. NREL maintains a world-class testing capability for solar reflectors, and they have developed a device called a Solar Simulator (SS) that maintains high light intensities (5X the sun’s intensity between 300 and 500 nm), controlled temperatures and relative humidities (up to 70°C and 70%RH) in order to achieve highly accelerated testing of reflector samples.
Solar Simulator results are shown in the figure below for the “New Reflector” (i.e. the ReflecTech® Mirror Film) and are compared against two other reflective film constructions (ECP-305+ and ECP-300 made by 3M) that serve as useful comparisons. 3M’s ECP-300 was a silvered acrylic film that had excellent optical properties, but limited outdoor weatherability. UV-induced corrosion of the metalized silver layer in ECP-300 generally limited the film to a 3 to 5 year outdoor lifetime.
3M’s ECP-305+ was a much more corrosion-resistant silvered acrylic film that was expected to have at least a 10+ year outdoor lifetime. Unfortunately, both of the 3M reflective films suffered from “tunneling”, a problem that resulted in 3M’s discontinuance of the product line. Nevertheless, the film was deployed in many field installations and was also well characterized in the laboratory through accelerated tests. Thus, these two 3M films provide convenient references for gauging the weatherability of ReflecTech® Mirror Film.
Download ReflecTech Film: Hemispherical Reflectance vs. Wavelength (.xml document).
Note that the “New Reflector” ReflecTech® Mirror Film construction compares favorably with 3M’s ECP-305+, a reflective film that was regarded as having excellent optical properties and superior UV-resistance. The data in figure above are for the samples subjected to the highest temperatures (70°C) and the highest relative humidity (70%) within the NREL Solar Simulator.
