An alternative technological solution for “issuing” solar electricity is proposed by British scientists. A team of researchers from the University of Edinburgh, under the leadership of Tapas Malik, developed universal light concentrators. They can be placed not only inside the glass pane, as the actual windows, and decorative exterior glazing, but also installed independently on the walls and roofs of buildings.
Each of the concentrators is a miniature tube, the extended open end of which captures sunlight, and in the narrow part is a photoelectric element. Compared with conventional solar panels, new devices will cost less (by 35-40%), since the basic material for them is ordinary plexiglas. According to the developers, the initial efficiency of the hub system reaches 20%, while up to 200 watts of electricity can be collected from each square meter of area equipped with them.
And this is not the limit: practical tests have shown that the new system makes it possible to rely on up to 75% of all the light entering the window for producing electricity.
As is known, up to 80% of the light falling on a glass coating turns out to be in a kind of transparent trap due to the effect of total internal reflection. It remains only to send it to the photoelectric converter and make it work. To enhance the effect, scientists suggested applying special paint on glass panels. Its molecules absorb light in a wide range of the visible solar spectrum, transforming them into light vibrations with a longer wavelength and directing them to photovoltaic cells located along the edge of the glass.
The basic principles of light-collecting coatings were developed in the United States in the 1970s, but practical implementation was achieved only in 2008–12, thanks to the work of specialists at the Massachusetts Institute of Technology under the leadership of Mark Baldo.
The coefficient of useful use of sunlight in the first experimental samples was rather small (5.6% -6.8%), and the coating itself was short-lived, because already after 2.5-3 months it was destroyed by the action of sunlight. However, in subsequent developments, the Baldo team was able to largely eliminate these shortcomings. Recent samples of a two-layer organic coating allow us to expect an increase in the energy efficiency. Windows are already up to 15-17% with a significant (up to 2-3 years) increase in the duration of their life.