You know those glasses that go from dark to light depending on whether you are outside in the sun or inside in the dark? Now, a couple of scientists have figured out a way to affordably do the same thing for windows. And their invention is expected to help cut down on energy costs – like expensive air conditioning bills by darkening to block out the scorching sun, or lightening in colder weather to capture the heat of the sun.
The smart window system, mentioned on EurekAlert, is a cheaper twist on an old idea. Windows that reflect sunlight away in the summer and switch back in the winter are nothing new. But they do come with a high price tag, short shelf life and can contain toxic chemicals. Researchers Ho Sun Lim, Jeong Ho Cho, Jooyong Kim and Chang Hwan Lee set out to find a way to correct those problems.
What they found was that a polymer, know as counterions, and a solvent such as methanol was an inexpensive and less harsh way to make a stable, robust smart window. The mix also was able to quickly and easily switch from opaque to almost clear in seconds.
Researchers say the new system may provide a new option for saving on heating, cooling and lighting costs through managing the light transmitted into the interior of a house. Details of the trio’s study appears in the journal ACS Nano.