There are few objects more exposed to wind and rain than windows!
The idea, floated around a team of researchers at the Georgia Institute of Technology, was to harness the power of these natural elements lashing against our windows to generate electricity through a triboelectric effect. This complicated term is usually associated with the appearance of static charges resulting from friction between two materials.
To achieve this, the researchers developed double-layered glass: the external layer contains nanogenerators that can capture the energy positively charged into raindrops when they come into contact with air.
The second layer is made up of two films of transparent plastic, PMMA, between which are placed small springs that react to the pressure of the wind.
When the wind's pressure pushes the sheets against each other, in accordance with the principles of the triboelectric effect, this reaction creates an electric current. By combining both layers, the researchers were even able to change the colour of their glass: transparent in the beginning, it then turned blue.
These very special windows could also be used in vehicles and buildings, provided that they are in contact with wind, rain or hail!
These nanogenerators are currently able to convert around 60 % of this energy into electricity. According to initial tests, they can produce around 130 milliwatts of electricity per square metre of glass. Enough energy to power the battery of a smart phone.