Sustainable textile facades - an inteview with the architect Jan Serode

    In the presence of Hamburg's Senator of Finance Dr. Andreas Dressel, the world's first nitrogen oxide-binding textile facade was launched in February 2020 on the campus of the real estate company ECE in Hamburg. The textile building shell, made of polyester, is attached to the outside of the front brick facade to filter toxic nitrogen oxides from road traffic. A research project at RWTH Aachen University led by up-and-coming architect Jan Serode is the driving force behind the project. In an interdisciplinary team of architects, ophthalmologists, textile, environmental and electrical engineers, he is developing sustainable textile facades at the Aachen University's Textile Institute. In the interview, he talks about how he wants to bring together sustainability, design and health in architecture.

    Mr. Serode, what was the motivation for you to conduct research on sustainable textile facades?

    As an architect, I was already very interested in research approaches for sustainable and environmentally conscious architecture during my degree course. Our buildings consume far too much energy. In Germany, buildings still account for 33 percent of CO2 emissions. This means that a great many of our buildings need to be upgraded in terms of energy efficiency. I therefore looked at how textile building envelopes are used today and, in the next step, examined the life cycle assessment of such building envelopes: What materials are textiles made of? How can textiles be improved ecologically? And what happens to them after use - are the textiles recyclable? In principle, any building can be wrapped with textile facades: Industrial buildings, offices, hotels, even parking garages. The textiles are pre-produced and the buildings can then be wrapped quickly. For residential buildings, this takes a maximum of two weeks. I encountered many prejudices against such textile facades at the beginning. Many people believe that with textile facades in place, you can't see out, that the textile facades are constantly dirty, and that there is no light inside. I wanted to refute these prejudices.

    The facade installed in Hamburg is an air-cleaning textile facade. What is it all about?

    Textile facades are generally attached to the outside of buildings, but they can serve very different purposes. The textile façade installed in Hamburg has a so-called photocatalytic coating that becomes active by itself when exposed to sunlight and binds nitrogen oxides. When it rains, these are then washed off again. Such photocatalytic surfaces already exist in other contexts, for example to repel dirt. In Hamburg, we now have a test surface in use for the first time. The project is accompanied by intensive monitoring. This is done with sensors that allow us to measure the extent to which air pollutants can be reduced with our textile facade.

    What does the textile facade in Hamburg consist of?

    For the nitrogen oxide-binding textile facade, known as the anti-NOx facade, we use polyester fabric that we first print and then coat with an ultra-thin film. The coating is absolutely color-neutral and the finished textile façade is 100 percent recyclable. To this end, we worked together with the environmental engineers to check in advance how we can separate the materials by type again at the end. Usually, at the beginning of the project, the clients ask about the environmental balance of the material. But when it comes to recycling the textile, very few are willing to think about it further. For me, therefore, the question is: What is the reason for this? And how can we make it easier for people to realize the full ecological potential of products like textile facades?

    How long can a textile facade be used? Will it need to be replaced at some point?

    How many pollutants can actually settle on the façade before the effect is exhausted has not yet been conclusively investigated. But I assume that we will not reach exhaustion. At least in Germany, we usually have high humidity and the dry periods are still manageable. But these are very exciting research questions that we are now trying to clarify with the project. Currently, we assume that even if it doesn't rain for several weeks, pollutants can still be collected.

    You are also working with ophthalmologists on the project. What is the reason for this?

    Our textile facade is hardly noticeable indoors. To this end, we have designed a microfabric similar to that used for fly screens. However, together with ophthalmologists, we are constantly checking how we can optimize the structure. After all, the more transparent the facade appears from the inside, the more likely it is to be accepted from the perspective of the viewer inside the building.

    This has also led us to the question: What do buildings with a transparent building envelope bring to the table? First of all, it means more light in the rooms and a stronger connection to the outside. Various studies show that contact with the outside, like a view of nature, leads to significantly better vital function values than in rooms with little transparency. I assume that this aspect will play an important role in architecture in the future.

    What weight does the so-called AntiNoX facade have within your research?

    The Anti-NoX facade is the variant that is very far advanced in our research. But we are also researching, for example, the so-called luminous façade, in which a luminous function can be integrated. Of particular interest to me is the photovoltaic façade, because it allows us to produce a solar shading system that can reduce the energy required to cool a building by up to 78 percent. It also creates a passive air-conditioning effect between the textile and normal building envelope. But we can also generate electricity with photovoltaic coatings on the textile facades.

    Which lessons have you learned from the project so far?

    Thanks to the discussions with the public, I see - even beyond the façade in Hamburg - that you can really make a difference with a creative idea. In my experience, the construction industry is very sluggish, so it's hard to introduce innovations here. On top of that, the industry is very driven by economic thinking. We are now testing a facade with coating here for the first time in practice. But there are also other ways to design the textile facade so that it has an air-purifying effect. These are research topics that require more money initially, but are ultimately quite feasible in economic terms. My goal is not to equip the whole world with textile facades. But they do show a good alternative to other building materials. Because textile facades are a system that offers many advantages in terms of environmental protection and climate protection - and at the same time offers very high design potential.

    Have you already received inquiries from companies or even private individuals?

    We are already receiving many inquiries about the anti-nox façade in particular, which we are of course delighted about. However, we still have to invest in the photovoltaic façade. Our technical concept promises great effects. If you are interested in getting more information about the textile façade, please contact me. We offer various possibilities here and are always grateful if someone supports us.

    What is your vision for the future?

    Buildings stand in the public space and have a surface or skin - which should primarily protect the interior. Then there is the design. But for me, the question also arises: What contribution can the facade of a building still make? And for me, these are particularly ecological aspects: Filtering pollutants, generating energy, saving energy and using energy more efficiently. It is important to show again and again by means of examples that such textile facades are not only functional, but can also look modern. Because without this, all the functionalities will not be accepted. So our task is also to approach good designers and explain, "This is possible - get creative!" In my experience, engineers in particular often lack design thinking. But if you can bring technology and design together, you can create extremely great things.