Scientists have combined three functions into one smart window design: light transmission, solar radiation to heat conversion, and sterility.
As essential architectural elements, windows are traditionally accused of compromising the energy performance of buildings.
Windows cause power bills to soar because of their adverse heating and cooling effects. During the hot seasons, they let hot air in. In winter, warmth oozes through them and out of buildings.
This is true, but windows are changing. While keeping all the functions we come to expect from them, windows are becoming more “smart“.
Other than generating power, smart windows can control light transmission, regulate the internal temperature, and even act as a shield against harmful microbes.
What if all of these functions were combined into one smart window system? Well, A team of Chinese scientists has done just that.
Photothermal Sterile Windows: Multi-Functional Smart Windows
Smart home technology can’t forgo the use of windows for a wide range of functions aside from their aesthetic and basic value.
Thanks to their ability to quickly switch from dark to clear and vice versa, electrochromic glass made of tungsten trioxide (WO3) can allow substantial power savings.
Such smart electrochromic windows are already in use in Boeing’s Dreamliner, but they have yet to make a foray into the building industry, especially because of their high costs.
There are also nanoparticle materials that enable smart windows to convert sunlight into heat.
Other smart windows made of copper-based materials have shown their antibacterial properties.
It’s impractical to have a separate system for each of these functions.
Now, a team led by researchers from Northeastern University and Nanjing University in China have managed to merge these three functions into a single smart window system.
The design of the “Photothermal Sterile Window” includes a 3D WO3-based “electrochromic-photothermal film” to monitor sunlight transmission, and gold nanostructures to convert ambient solar radiation into thermal power.
The photothermal properties of the system (up to 24 °C in five minutes) ensure its bactericidal antimicrobial effect, which researchers tested on E. coli bacteria, and found it to be at its best when the glass is in dark state.
“The sterile smart window would be particularly useful in aircraft, in high-latitude zones, and also in hospitals,” said Xing-Hua Xia, co-leader of the research. “It should be multifunctional, for example, controlling visible light transmission dynamically, tuning heat conversion of near-infrared solar radiation, and reducing attacks by microorganisms.”