The MOST window film keeps rooms from heating up during the day, but warms them at night(Credit: Yen Strandqvist/Chalmers University of Technology )
A couple of years ago we heard about the MOlecular Solar Thermal (MOST) system, in which solar energy is stored in a liquid medium, then later released as heat. Now, the technology has been applied to a clear film that could be applied to the inside of windows in energy-efficient buildings.
Developed at Sweden’s Chalmers University, the MOST film incorporates a norbornadiene–quadricyclane molecule. This causes the transparent polymer film to take on an orangey-yellow color when not being directly exposed to sunlight.
Once the sun rises in the morning and its rays strike the material, however, much of the sunlight’s solar energy is absorbed by the molecule. More specifically, the molecule captures some of the incoming photons, causing it to isomerize – this means that it temporarily becomes another type of molecule, with exactly the same atoms but in a different arrangement.