Anti-heat, anti-UV or electricity generating … a new generation of windows is arriving. With, the key to success, less energy wasted on air conditioning.
Intelligent windows have already been seen to be capable of improving the thermal comfort of buildings through a ventilation system. But a window that can darken or lighten without requiring an external power source to operate? A window capable of producing its own energy and its surplus to power LEDs … or serve as a rechargeable battery? The concept was developed by a team from the Nanyang Technology University in Singapore in 2015.
Since then, a handful of European start-ups have seized on the idea. Having reached maturity, their technologies are entering the market this year and could cause a minor revolution in buildings because, instead of drastically reducing energy consumption, they draw it directly from the source. Better, they create it.
In the family of active glazing, one using electrochromic technology is arguably one of the most revolutionary. And among the few industrial applications presented for sale, Saint-Gobain’s SageGlass range for facades and glass roofs is one of the most innovative. These electro-sensitive windows detect the amount of light and solar heat. If the heat or light is too strong, an electric current darkens the glazing. As a result, this installation reduces the need for artificial lighting, diminishes heating and cooling costs and consequently the maintenance and operating costs of the building. A little jewel of technology that has been the subject of the filing of more than 500 patents.
When the sun controls the window
And if the glazing was able, in addition, to produce energy? It is in this sense that Vinci Construction and the start-up Sunpartner Technologies have designed Horizon. This window combines electrochromic glass technology (SageGlass from Saint-Gobain) with that of integrated photovoltaic glass, which is used by Sunpartner’s Wysips Glass process. Specifically, the energy from the transparent photovoltaic glazing enables the opacification of the SageGlass glass to be controlled. The control is provided by an electronic box connected to a mobile application. Suited for renovations as well as new constructions, Horizon would enable an energy reduction by around 30%.
The precursor of flexible photovoltaic films and funded by Engie, the German company Heliatek markets one of the most promising Green Tech technologies in the world, a small piece of plastic, quite thin – less than 1 mm – that houses the transparent photovoltaic cells based on organic matter (not alkaline silicon). Bonded onto facades, roofs or double glazing, its efficiency is similar to conventional solar panels: up to 80 watts per square meter depending on the sunshine. Which would make many buildings autonomous.