We are talking about a project of nano-engineer Ioannis Papakonstantinou - advanced windows that can automatically control the amount of heat and oxygen entering the room. They will save people from the need to install expensive and energy-consuming air conditioners in summer, and in winter to waste precious heat due to low-quality double-glazed windows. And you don't need to wash this wonderful window (!).
According to Papakonstantinou, about 75% of buildings in Europe are not energy efficient. They are old and do not retain heat, which leads to high financial costs for heating in winter. And in the summer they require the installation of air conditioners so that oxygen gets into the building and cool air circulates. Despite the investments in this area, no one could figure out how to modify the windows so that they serve as the source of that notorious energy efficiency.
Ioannis not only complained about the shortsightedness of the European governments and local inventors, but also created the IntelGlazing project in 2016. This is a large-scale research work at the intersection of nanotechnology and photonics (a discipline that studies optical signals), designed to revolutionize the world.
Cool nano window
The IntelGlazing project involves the use of windows with a two-layer multifunctional coating.
The first layer is a thin nanoglass in the form of small "hairs" less than a micrometer (one thousandth of a millimeter) in length. They overlap and scatter sunlight coming through the window.
The second layer (which helps to achieve the very same energy efficiency) is vanadium oxide, which clings to nanofibers from the first layer. This material is prone to thermochromia, that is, it changes color depending on temperature. For example, on a hot day, vanadium oxide will change its structure, darken and reflect from the window part of the infrared solar radiation, which would heat the room in the case of a standard window. On colder days, on the other hand, the system will "brighten" the window and let more sunlight into the room. It turns out a kind of automated toning.
Sounds cool already, but that's not all. Firstly, this miracle of nanoengineering can be applied to new windows at the glazing stage as well as to existing ones. It is enough to modify the old glass with a layer of nanofilm from Professor Papakonstantinou.
Second, window manufacturers can change the chemistry of vanadium dioxide and adjust the “darkening” and “brightening” temperature limits for different countries and their climates.
For example, in Spain, you can raise this border so that the windows begin to block the light after a conditional 25 degrees Celsius. This will avoid overheating the room. In Sweden, on the other hand, the darkening limit should be lower so that people's dwellings receive as much heat as possible from the rarely-appearing sun.
A nano-window that doesn't need to be washed
The invention of Professor Papakonstantinou is not only thermochromic, but also hydrophobic (water-repellent). The liquid on the film does not linger and instantly rolls down, clinging to all the dust that has accumulated on the window during the day.
The creators of the technology note that this will significantly reduce the cost of maintaining windows in skyscrapers. Apparently, this means hiring climbers who regularly clean windows in high-rise buildings from the outside.
Nano-window (almost) as an alternative to air conditioners
But not a single film is a good invention of Papaconstantine. The window has a special design, which provides for two valves: one launches oxygen from the street into the glass unit, and the second lets it into the room.
While the air is in a three-layer glass unit, it is warmed up by the sun's rays and enters the room slightly warm. As conceived by the authors of the project, this entire system should be controlled by mini-fans capable of retaining heated air until it reaches the desired temperature. If the film darkens the window, after prolonged recirculation of air in the glass unit, cooled air will enter the room through the valve.
Subsequently, the renewed oxygen in recycled form must leave the room through standard ventilation. According to the creators of the smart window, this will reduce the cost of installing air conditioners, because almost all rooms have windows, but not all of them have room for complex air conditioning systems.
A nano-window that protects nature
The goal of the project is energy efficiency. There is a task to reduce energy costs by about 25% and make smart windows more competitive in comparison with other similar solutions due to vanadium oxide, which is activated automatically and more intelligently controls incoming heat and "fresh air".
Scientists have been discussing similar problems for several decades. Now initiatives in the spirit of IntelGlazing are spiced with the general movement of civilized humanity to reduce carbon dioxide emissions and try to prevent the development of the greenhouse effect.
Against this background, the ideas of Ioannis and his colleagues look even more promising, and therefore are actively promoted. The sooner nano-windows enter the market, the sooner people will replace old windows with something innovative, energy efficient and environmentally friendly.