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Climate idea

Adapting to climate change: the sponge facade

Climate adaptation: House facades have so far hardly been used for climate adaptation measures. The heat builds up in the city centers in summer. A new type of storage element for house walls could cool the environment - and also protect against flooding. Extreme weather becomes normal. The German Weather Service has observed that heat waves have recently increased in frequency and intensity. Temperatures over 30 degrees in this country and blazing heat of 40 degrees in the Mediterranean are no longer uncommon. In addition, there are dramatic changes in the weather with storms and heavy rain. In some places, as much water rushes from the sky in one hour as would otherwise be the case over a month. The heat builds up particularly in the inner cities with their sealed areas, dense buildings and deep street canyons. At night, stone, concrete and asphalt release the heat stored during the day into the environment, preventing the air from cooling down. The increasingly frequent heavy rain is overwhelming the sewage system, which is not designed to handle such volumes of water in a short period of time. The result: full cellars, flooded streets and damage to the building structure. “We would actually have to react very quickly now,” says Martina Winker, an expert on water infrastructure at the Institute for Social-Ecological Research ISOE. But adapting the pipes and collection systems of the city sewer system, the sewage treatment plants and the water supply would mean enormous construction work over the years. “We don’t have that time,” emphasizes Winker. That's why, at the same time, a move has been made to no longer just channeling and draining rainwater under the heading "sponge city", but rather storing it locally and making it usable on site - through unsealing, green roofs, and infiltration troughs. What has so far received little attention is the sponge potential of facades. And that is huge. One element stores around 8,100 liters of water Researchers at the Fraunhofer Institute for Environmental, Safety and Energy Technology (UMSICHT) have calculated that 4,200 liters of water rain down on the roof of a typical inner-city apartment block of 420 square meters within 15 minutes of heavy rain. Water that often flows unused through the roof drainage and, in the worst case, causes the sewer system to overflow. “We would like to store the rainwater that occurs on the building directly on the building and use it profitably,” says Holger Wack, deputy department head for product development at the institute. A team is developing a new type of storage element, the “Vertical Water Sponge”. This vertical sponge consists of modules with a load-bearing, permeable shell, for example made of perforated sheet metal, and a water-storing filling made of mineral materials. Ideally, shredded materials from recycling processes such as bricks, sand-lime bricks, aerated concrete, which have very good water storage capacities, are used for the filling. The modules are placed one on top of the other, mounted on the facade and connected to the roof drainage. According to the development team, such a sponge element with a width of one and a half meters and a depth of 50 centimeters with an eaves height of the building of almost eleven meters stores around 8,100 liters of water - depending on the filling material. “This means we can also absorb long-lasting precipitation or heavy rain events that occur several times in a row, especially since it is possible to mount several elements on a façade,” explains Holger Wack. "So we can quickly remove large amounts of water from the system." The water should not only be stored, but also contribute to improving the microclimate in the immediate area through evaporation - hence the perforated sheet metal. Not least due to the large surface area of the shredded filling materials, Fraunhofer UMSICHT expects a cooling effect over several days. Many experts believe that increasing reliance on evaporation makes sense, and not just in view of future heat waves, says water infrastructure expert Martina Winker, who is not involved in the project. "Colleagues have determined that a strong focus on infiltration alone is not enough. Our cities need more evaporation to support the water cycle."

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  • We Don't Have Time

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    Dear Patrik Lobergh Your climate idea has received over 50 agrees! We have reached out to Fraunhofer-Gesellschaft by email and requested a response. I will keep you updated on any progress! To reach more people and increase the chance of a response, click the Share button above to share the review on your social accounts. For every new member that joins We Don't Have Time from your network, we will plant a tree and attribute it to you! /Adam, We Don't Have Time

    • Judy Holm Climate Designers

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      Ingenious 💚

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