I still remember when, as a child, I was enchanted watching the raindrops slide on the window glass. A small race between tiny liquid runners, who competed in an almost hypnotic race. A group of Korean scientist-dreamers have decided to give them a new purpose: to power the future. Get ready to see the rain with new eyes.
A shower of innovation
All 'Seoul National University, a team of researchers led by Professor Seung Hwan Ko decided to change the way we see ordinary windows. The result? A “smart” window that makes old double glazing look like relics of a bygone era.
This, my dears, is not just a window. It's a miniature power plant, cooling system and anti-freeze device – all in one.
Drops of rain and energy
The special feature of the window developed by the Seoul researchers lies in its ability to turn raindrops into usable electricity. Imagine being able to power your smartphone with the energy of a summer storm: thanks to a triboelectric nanogenerator (TENG), each drop of rain that hits the window generates a small amount of electricity.
“In an experiment simulating rainy conditions, smart windows they generated 8,3 W m-2 of power with a single raindrop,” reports the press release.
It's not much, but consider this: on a rainy day, how many drops hit your windows?
A reflection of genius
The surprises don't end there. These windows are also masters of multitasking. Thanks to a layered structure of silver and indium tin oxide (ITO), they manage to reflect much of the infrared thermal energy, keeping the interior cool without losing its transparency.
It's like having an air conditioner, but without the energy consumption. In fact, researchers say these windows can maintain a temperature about 7 degrees lower than normal windows in hot environments and under direct sunlight.
What about those who live in very cold climates?
Well, these windows have a surprise for them too. Through a process called “Joule heating”, they transform into transparent self-heating electrodes, automatically defrosting on cold days.
According to the researchers, these windows free themselves from frost “twice as quickly as normal windows”.
Towards positive energy buildings
Professor Ko and his team, if you hadn't understood, have a rather ambitious goal: to move from zero-energy buildings to positive energy buildings (PEB). Buildings that not only minimize energy consumption, but also produce energy independently.
“It is necessary to develop multifunctional smart windows equipped with transparent cooling technology (based on zero energy) and additional energy harvesting technology (based on positive energy) that ensures sustainable power,” explains the team.
Will they make it? Maybe. The doctor Yeongju Jung, lead author of the study (that I link to you here), is conducting further research to improve the design with the ultimate goal of creating a commercially viable window. At that point the market will speak.
Drops (of rain) in the sea of change
As the world struggles to reduce dependence on fossil fuels and improve energy efficiency, innovations like this smart window offer a ray of hope. Or should we say, a drop of hope?
Professor Ko eloquently summarizes the potential of this technology:
“Smart windows are expected to be applied in various industries because they address environmental pollution, reduce cooling energy, and overcome the limitations of conventional battery technologies through self-generation of energy.”
The next time you see rain beating against your window, don't sigh in frustration. Instead, smile and think of the day when every drop will help light up your world. The future, it seems, could be right behind your window glass.
