October 27, 2013 - Scientists in China
said Thursday they had designed a ‚Äúsmart‚ÄĚ window
that can both save and generate energy, and may ultimately reduce heating and cooling costs for buildings.
While allowing us to feel close to the outside world, windows cause heat to escape from buildings in winter and let the Sun‚Äôs unwanted rays enter in summer.
This has sparked a quest for ‚Äúsmart‚ÄĚ windows that can adapt to weather conditions outside.
Today‚Äôs smart windows are limited to regulating light and heat from the sun, allowing a lot of potential energy to escape, study co-author Yanfeng Gao of the Chinese Academy of Sciences
‚ÄúThe main innovation of this work is that it developed a concept smart window device for simultaneous generation and saving of energy.‚ÄĚ
Engineers have long battled to incorporate energy-generating solar cells into window panes without affecting their transparency.
Gao‚Äôs team discovered that a material called vanadium oxide (VO2) can be used as a transparent coating to regulate infrared radiation from the Sun.
VO2 changes its properties based on temperature. Below a certain level it is insulating and lets through infrared light, while at another temperature it becomes reflective.