Fresh air for the compressed Zürich

Only a bird's eye view you realize that there is something wrong could be. You are standing on the ground, between the curving rows of houses on the slopes of the Uetliberg, just a beauty. Pretty wooden facades, spacious colonnades painted. No wonder, has awarded the city of Zurich, the co-operative settlement in green matte, this modern Interpretation of the garden city, managed as a particularly. However, if we look down on them from above, looks you in the ground with a crack like a series of dams and reservoirs – and that could result in this pattern of settlement has to one day serve as a negative example.

city climate plan

This has to do with the professionals of the civil engineering Department have recently announced, what do you imagine under the internal compaction of Zurich concrete. A municipal settlement plan shows where and how to accommodate those additional 100'000 residents to create, the are expected by 2040, without including the quality of life suffers. Because you want to do it particularly well, in the planning of any aspect, except for Eight – not even the climate of the city, the importance of which during the heat of summer is lots of become aware of.

The key question is: How can you condense Zurich structurally, without the stifling cold air trams, which the inhabitants of the city, in hot nights, a little sigh of relief? It is all the more urgent, as a substantial part of the expansion, according to the indicative plan, close to the Northern slopes of the Uetliberg, the Käferberg and the zürichberg is to take place. So, where at night the cool air, as with invisible fingers, into the city attack. Which way you choose, clearly shows a climate analysis of the Canton, published in June. You could follow a mosquito, which leaves around four o'clock in the morning on the edge of the forest of the Uetliberg mountain from the cool air flow support, as one would glide first over the graves of the Jewish cemetery and then over the adjacent allotments. In the case of the reservoirs of the green, Matt, settlement no would get Through, so it was up to the left, to the roar of the tree-lined döltschi Bach along and across the Football field at the nearby school.

At the height of the Badi Heuried wins the travel speed, so that the thrust is sufficient for the flat piece on the loose, cultivated meadows to the Toblerone-shaped Thomas Church, a school house, and the next to the allotments, before the pours flow of cold air in the cemetery Sihlfeld. From there, its last offshoots reached after a journey of about two kilometres, the Fritschi-meadow, where the mosquito is one of the last feast, brothers, of the just comes from the Idaplatz, stands with relish in the back of the neck.

This cold air path crosses the road halfway to the Birmensdorf – one of the areas to be compacted in accordance with the structure plan of an urban center area. This means that perimeter block development and building fronts of up to seven storeys in height. The poet is not. The indicative plan leaves open the question of how such conflicts are to be solved. On the part of the urban professionals, it means that this is a "highly complex issue" that will make the already difficult planning even more complicated. Especially since it is missing, unlike in the case of noise protection, currently entirely on legal principles, in order to make the builders of any of the provisions. The answers you hoped for from the city's "master plan climate" that is currently a work in progress.

Stuttgart shows

A good chunk any further in such matters, in Stuttgart, a city that is similar to Zurich in a Hanging surrounding the boiler. There, one has a "urban climate Handbook" with specific recommendations for builders. Submitted by the Department for Urban climatology, an Institution with 80 years of experience. Their Expertise goes back, curiously, to the national socialists, who sought in the war, the city of artificial fog to protect them from bomb attacks. But the fog was not absolutely there where you wanted him – so it was discovered that the nocturnal cold-air currents.

Green open spaces ideal

head of Department Rainer Kapp, says it is testing in Stuttgart, the axes of motion of the air currents, as far as possible. However, one also knows the imperative of an inner compression, and to prevent urban sprawl. If you do not get around on a slope to a building, locker buildings clustered single over closed lines to prefer. No dams. As the cold air lanes green, according to Kapp-free surfaces ideal.

the Valley course at the end of streets with no trees to offer eats to the air, although there has also been little resistance to flow, but, according to Kapp, a decisive disadvantage: "Heated Asphalt, thermally seen, the cold air." All these requirements also apply to the Transition from the slope to the basin, so that the cold air penetrates as deep as possible in the city.

While working in Stuttgart today in the assessment, mainly with computer simulations, it is raised in large cities such as Berlin or New York, a complex Monitoring of the air flows with a dense network of measuring stations. In Hamburg in turn, researchers have recreated in a wind tunnel, among other things, a whole part of the city of Basel in the model, to study turbulence in Detail.

The first advantage of this complex approach: You have exact measurements. The second: You can make forecasts, what is the impact of future changes, by testing them on the model. So the ETH to explain to Professor Jan Carmeliet and his colleague Jonas Allegrini from the research Institute Empa in dübendorf. There, in a windowless hall that experiment for years, with urban landscapes on a miniature scale, which you set up in a wind tunnel the Size of a truck. Since this year, they are still a step further: you have also taken a water channel that allows it to simultaneously measure the flow temperature also changes.

How does the research at Empa exactly explains this Video in English. Video: Empa

Carmeliet and Allegrini, due to their Attempts amazing clear ideas of what to do would be to a city like Zurich as well as possible to ventilate. These are, however, partly in contradiction to the ideas that have aesthetic, urbanistic or social reasons, especially economic. The popular perimeter block development, for example? "Not good at all." However, let its balance sheet to significantly improve, if you open it in at least two corners, says Allegrini, in the direction of the wind.

Different houses

Also dams and reservoirs on the hillside are from the climatic point of view, a No-go. If the slope of parallel slices, then treated like a zipper. Better yet, you in the direction of the Slope, and thus of the wind. But Carmeliet is aware that strong economic reasons speak against it: "The people want a view."

another finding that runs counter to current Trends: the more irregular the building is, the better for the ventilation. All the houses are the same, the heat in the in-between spaces such as in a drum caught while the Wind blows above the roofs. Corrective, selective to bring high-rise buildings, because they generate currents of air to the street level. There, in turn, should ensure that the air can freely move by the houses, for example, as in the post – war period to Support Le Corbusier would be pleased.

studies in Zurich have shown that even strong air currents such as those from the sea have to part after the first row of houses of no effect. To change this, you have to build Carmeliet, according to permeable. "We also know how to do that," he says, "but the Problem is: The city planners have heard so far." That could change, at least in Zurich soon.

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Created: 28.12.2018, 21:21 PM