3M Athermal Films: Transmit Light but Not Heat
Facade glazing has been popular for decades: buildings, lined with glass, look modern, attractive and provide endless opportunities for self-expression of architects and clients through selection of glass of various colours, creation of casts and play of reflections.
At the same time requirements for thermal and operational characteristics of a facade, serving the only type of building envelope, have been increasing. The situation with outdoor use is more or less clear: glass is durable, it is not subject to destructive climatic factors, and periodic cleaning of external surfaces of skyscrapers with the help of industrial climbers has already ceased to be exotic. On the other hand, a situation with thermophysics and interior comfort is not so smooth. Glass barriers transfer natural light together with an infrared thermal component of the spectrum.
Panoramic windows help to maintain substantial energy savings through better use of natural light, but «additives» in a form of invisible (to the human eye) ultraviolet and infrared rays create a lot of trouble for people inside the building. With the first spring sunshine a modern skyscraper with panoramic windows is transformed into a greenhouse or a wig. The situation persists throughout the summer season. Ultraviolet rays influence fading of fabrics, plastics (including office equipment), decorations and other materials.
Modern conditioning and ventilation systems, all kinds of blinds and curtains, glass, coated with sunscreen, can eliminate such discomfort. The named glass (for example, «StopSooll») has a mirror coating of different densities, reflecting sunlight and reducing amount of heat, penetrating into rooms in summer. The level of protection from excessive solar heat reaches 52%. However, this glass has a serious common drawback – it reduces a flux of solar radiation in the visible spectrum. This article describes an alternative to a simple energyefficient window glazing: a new method to protect you from solar thermal energy coming through windows using optically transparent films.
Beginning a conversation about optically transparent films, remember that white light, ultraviolet (UV) and infrared (IR) radiation form all ranges of the electromagnetic spectrum along with Gamma and X-rays. In this article we’ll talk about solar spectrum in the wavelength range from 0 to 2.5 nanometres (nm).
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Materials provided by the 3M Company