On a sunny day, even an air-conditioned building can be too warm. A predominate factor is simply your windows, which let in heat in the form of invisible ultra-violet light even if they’re insulated and well-sealed. But a new advance in glass-making technology might change that, allowing your windows to block out light and heat-raising ultraviolet light, interchangeably.
A new type of glass has been invented by a group led by Delia Milliron, a professor of chemical engineering at the University of Texas at Austin. It’s basically a new type of smart glass, a glass that clouds over and blocks out light when it is exposed to an energy source like heat or electricity. Think transition lensed eyeglasses, but for buildings.
Some types of smart glass can already help keep air-conditioning costs down by blocking out wavelengths of light, but historically, they haven’t been able to block out ultraviolet. This new type by Milliron and her team can.
Here’s how it works. Milliron’s approach uses a framework of nanocrystals made of an electrically conductive material, embedded in glass. The nanocrystals can either block ultraviolet light or allowthem to pass through, while the glass can transition from transparent to opaque, darkening or lighting in response to energy. In the end, the nanocrystals can block up to 90% of UV light and 80% of visible light. Windows made of such glass can transition between three modes: the standard bright and dark modes of traditional smart windows, which block or let in visible light, and a cool mode, which saves on electricity bills by blocking out invisible ultraviolet light wavelengths that can penetrate even a smart glass window gone dark.
Milliron says that the technology is sufficiently advanced for her to go ahead with a new start-up, Heliotrope Technologies, which will bring it to market. And she says that her glass is actually easier to manufacture than many other types of smart glass, which generally suffer from slow yields and requires a lot more energy to work. Although smart glass has been around for decades, it’s still relatively rare to see installed in the wild. Maybe this new leap will finally change all that.
[via MIT Technology Review]