Doctoral student Mohammad Taha with a sample of coated glass Credit: RMIT
There are already energy-saving “smart glass” windows that can be electronically tinted to block the sun’s hot rays, thus reducing the need to run air-conditioning systems. Such systems still require electricity to operate, however. Now, scientists from Australia’s RMIT University have developed a coating that allows existing glass to become smart … no power required.
Composed of relatively inexpensive vanadium dioxide, the self-regulating coating is just 50-150 nanometers thick. That’s approximately 1,000 times thinner than a human hair.
At surface temperatures below 67 ºC (153 ºF), vanadium dioxide acts as an insulator, helping to keep indoor heat from escaping through the window glass – it also allows the full spectrum of sunlight to enter from the outside. At temperatures above 67, however, it transforms into a metal that blocks heat-causing infrared solar radiation from entering.
This means that rooms stay warmer when temperatures are lower and cooler when they’re higher, allowing for less use of both heating and air-conditioning […]
I’d like to know if this coating would perform better than standard ‘hard e-coatings’ for passive solar heating in northern climates, especially given that large glass panes “float”, therefore easily breaking their seals over time, losing argon gas and eventually becoming enveloped in water vapour.