A new technology has been developed to improve building windows, which are deemed as the least efficient as they are responsible for 60% of total energy lost. Nanyang Technological University’s Yi Long and her colleagues solved the problem by inventing a smart window that automatically regulates the radiative cooling by turning the process on or off depending on the temperature affecting a building.
Radiative cooling is the process of radiating thermal energy inside buildings, which takes place when the windows outside during warm weather radiate heat inside, which increases demand for cooler air produced by air conditioning systems. Conversely, windows warmed from the inside during cold seasons tend to radiate the heat outside, which increases the demand for heat produced by indoor heaters.
What Makes a Smart Window Work?
The group of scientists from Nanyang Technological University added a a thin layer of vanadium dioxide on one side of the glass, whilst adding vanadium dioxide, a compound that transforms an insulator into becoming a conductor once temperature reaches 68°C. If the temperature is below 68°C, the smart window will prevent infrared radiations from the inside from escaping. At the same time, the window technology will reflect the heat on the outside.
On the other hand, since a 68°C temperature is an extremely hot temperature that does not occur even during the warmest weather conditions, the team added tungsten to the vanadium dioxide as a way to lower the transition temperature to 28°C.
In between the tungsten-clad vanadium dioxide and the glass material of the smart window, the researchers added another layer of transparent poly(methyl methacrylate) or PMMA plastic, to improve the smart window’s insulating abilities.
According to Long, the smart windows do not require electricity when adjusting to the temperature everyday. Still, the team of researchers are still working out a few more improvements before making them commercially available, including its durability nad utmost ability to block infrared radiations.