Textile facade soaks up pollutants from the air

Numerous studies show that nitrogen oxides are harmful to both humans and nature. The main cause is, above all, the traffic on the roads. An architect from Aachen now wants to trap this number-one air pollutant using coated fibres.

It was when Jan Serode was in the seven-million-strong metropolis of Santiago de Chile, where there has also been talk of environmental emergency because of the high concentration of noxious substances, that he was struck by an idea for a clean-up. Couldn’t we perhaps stretch something over the facades of buildings to protect them and the environment against air pollution? So, during his architecture course at the Technical University of Berlin, Serode analysed a host of traditional materials used in the construction industry: stone, steel, concrete, glass, wood. “However, I am rather more interested in textiles as an innovative building material,” he says. And so, since 2016, the now 34-year-old architect has been researching, at the RWTH Aachen University, ways in which textiles can be usefully used in architecture to protect both the environment and people’s health, whilst at the same time creating buildings with a modern design.

Coatings that bite
Finely woven fibre coverings have long since represented a playground of lightweight building opportunities, where more and more new, eye-catching buildings have continued to spring up. With his translucent, see-through, anti-NOx textile facade in Hamburg, post-doctoral researcher Serode is now seeking to demonstrate that fibres have potential uses way beyond their ability to create eye-catching designs. NOx is the chemical formula for nitrogen oxides, which are, of course, not confined to the air in Hamburg. Installed on the outside of the office block of his project partner, building consultants, ECE Europa Bau- und Projektmanagement, the new style facade, made from polyester and designed by Serode, has been swallowing up nitrogen oxides from the air in the north German town and absorbing them chemically since the beginning of February. This is made possible by a coating of nano titanium oxide. It converts the invisible noxious substances into harmless salts, which the rain can then wash into the drains. “With no danger whatsoever”, adds Serode. In fact, the reverse is the case: the water containing the salts could theoretically even be collected and used to fertilise plants.

Textile air cushion
As well as its air-cleansing properties, the facade, which has built-in sensors to monitor its efficiency in cleaning up the atmosphere, can also act as an external sunscreen. “Cooling internal spaces incurs huge energy costs, as materials such as concrete and glass warm up rapidly,” explains Serode. An external textile facade hung in front of the building, on the other hand, acts as a sort of air cushion, rather like the corrugated cardboard round a hot cup of coffee. “Our studies show that, with the textile facade, we can reduce the solar cooling requirements in summer by up to 78 percent,” says the specialist in environmentally aware architecture, commenting on the effects of the facade system on energy usage.

Research under the eye of the ophthalmologist
According to Serode, sceptics are often critical of textile facades on the grounds that their grid-like structure would prevent light coming in and people seeing out. “That isn’t, however, true,” he insists – and has therefore invited two eye-specialists to work with him on his research. “They check the extent to which the fibre-based facade affects people’s perceptions. Many of them are surprised, says Serode, that they don’t really notice the textile structure at all, or are hardly aware of it, when they look out of the window. The reason for this is the delicacy of the ‘holes’ in the texture of the weave and the evenness of their distribution.

The architect takes it as read that the trend for textiles stretched in front of external walls will continue. He is already working on other ideas; he and his research team have, just recently, presented a version of the external facade made from recycled plastic bottles. In future they are hoping to weave tiny solar cells into the fabric. “The Hamburg project was our first shot,” says Serode, “but there is still a lot more in the way of innovative building ideas to be developed with textiles.”

Title image ‘Facade’ (Source: ECE)