Using sunlight, the façade filters harmful nitrogenous substances from the air and then converts them into harmless nitrates. The nitrates are then washed off the façade by rain and then serve as fertilizer for plants and enrich the soil.
The textile facade is already being tested in downtown Cologne from April 2024 and measurements will continue until the end of 2025. The photocatalytic filter consists of two printed membrane surfaces of 8 x 20 meters each (total area of about 320 square meters) and features digital measurement technology. The membrane filters harmful nitrogen oxides from the air using applied actives and converts them into harmless nitrates. With measurement technology, the air quality in front of and behind the membrane is measured to evaluate and document the air purification effect.
Three flies
In addition to its air-purifying effect, the textile also saves energy by keeping the building cool with its solar control fabric. At the same time, the membrane radiates less heat, thus also cooling the city. More than 4,400 recycled PET bottles were also used in the production of the textile façade, and the aluminum for the supporting structure is 75 percent recycled material.
Filter performance
According to manufacturer Schüco, measurements show that, based on average monthly values, a filter performance of 30 percent is achieved. Individual daily measurements are even higher. "Moreover, the filter performance is continuously improving," said Michiel Prijs, Marketing Manager at Schüco. These percentages can additionally go much higher, he believes. "After all, sunlight activates the process and the facade is now located on the low-light north. The project shows that filter performance increases with longer daylight hours and higher temperatures. So with a south-facing membrane, the filter performance will be even significantly higher."
