Smart windows deliver significant energy efficiencies
Buildings are responsible for about 35 % of greenhouse gas emissions in the EU, as well as 40 % of all energy consumption. Improving energy efficiency is therefore central not only to achieving ambitious carbon-neutral goals, but also to coping with current energy price rises. “One of the weakest links in building energy efficiency is windows,” says IntelGlazing project coordinator Ioannis Papakonstantinou from University College London in the United Kingdom. Many windows are still either single or first-generation double-glazed, which means they do not offer particularly great insulation qualities. “They are also static,” adds Papakonstantinou. “This means that they are only suited for one type of climate, and are not adaptable. Given that most Europeans experience continental or temperate climates with relatively cold winters and hot summers, this is suboptimal.”
Improving energy efficiency
To address this deficiency, and to help Europe meet its energy efficiency goals, the IntelGlazing project, funded by the European Research Council, set about developing more intelligent windows. For this, Papakonstantinou and his team looked at the potential of nanostructured glass. “The idea is that this glass adapts its performance to suit different temperatures, by letting in solar radiation during the winter, and rejecting solar radiation in summer,” he explains. The amount of radiation escaping or entering a window depends on the ambient environmental conditions outside. The project was able to demonstrate the reactive qualities of this glass to ambient temperatures and radiation absorption. The team was also able to explore other potential functions of the nanomaterial. “Reflecting or absorbing solar infrared radiation is just one possibility,” says Papakonstantinou. “Another could be self-cleaning, because the nanostructured surface interacts differently not just with photons but also with fluids.”
Attracting industry interest
A self-cleaning – and antimicrobial – glass surface could be of huge interest to touchscreen manufacturers, as well as to hospitals and public transport operators. The project team also examined possible anticondensation properties, which has attracted interest from the automotive sector. “There has also been a lot of interest from the glazing sector,” remarks Papakonstantinou. “One reason for this is that we also pioneered a manufacturing breakthrough.” Nanostructured glass typically involves multiple costly steps. The IntelGlazing project however was able to come up with a method to fabricate nanostructured glass in just two steps. “As we are a research lab, the next step would be to start thinking about how to scale up production,” adds Papakonstantinou.
Intelligent polymer film
The successes of the IntelGlazing project do not stop there though. In the process of working on nanoglass, the team happened to discover a novel way of managing heat emission (as opposed to solar radiation), through the application of a nanocomposite polymer film. “What this means is that if you have a heat reflective coating on your roof and apply this film to the surface, it will continue to reflect heat in the summer, but retain heat in winter,” explains Papakonstantinou. “This means that your roof would ‘switch’ on and off according to the ambient temperature, like air conditioning, but without any energy used.” Both the intelligent glazing and polymer breakthroughs are in the early stages of development, but Papakonstantinou and his team are excited about the eventual market potential. If successfully scaled up, both technologies could deliver significant energy efficiency savings, at a time when Europe needs such smart solutions.
Keywords
IntelGlazing, windows, energy, solar, radiation, climate, polymer, glazing, automotive
