Nano-layer and micro-structure technologies for energy efficiency and sustainability

T.J. Hebrink
3M Company,
United States

Keywords: multilayer, nanolayer, microstructure, optical film

Summary:

Multilayer optical film technologies made with hundreds of nanolayers and microstructured film technologies can be used to manage building energy while maintaining architectural aesthetics. For example, visibly transparent (invisible) infrared mirror films are useful for rejecting infrared energy from building windows, and walls, to reduce air conditioning cooling energy loads by 10-30%. Rather than just rejecting infrared energy, the infrared energy can be redirected to where it may be converted to electricity, or solar thermal energy, with concentrated solar optical designs made with these transparent infrared mirror films. Infrared concentrated solar designs have been modeled which simultaneously provide building daylighting and solar energy generation. Nanostructured and microstructured films can be used for anti-reflection to capture more solar energy for solar panels and greenhouses. Both multilayer optical films and microstructured films can be used to bring daylighting further into a building enabling reduced electrical energy consumption for lighting. 3M Company manufactures specular mirror films having greater than 99% reflectivity and this high reflectivity enables ducting of sunlight greater distances into a building without loss in light quality. 3M Company’s precision microstructured film technologies have been applied to windows to refract light further into a building while simultaneously reducing unwanted glare. Multilayer optical films are also useful for passive radiation cooling during the day. Previously, passive radiation cooling was demonstrated for cooling only at night, but more recently, broadband solar mirror films created with multilayer optical films has enabled passive radiation cooling in broad daylight. Multilayer optical film technologies have been applied to the creation of Ultra-Violet mirror films which are useful for providing durable long lasting film protection in outdoor applications.