Due to climate change, rising temperatures lead to more extreme heat stress in urban areas. Last summer, there were poignant images of people looking for shade in cities. Trees are effective measures to provide shade and decrease the perceived temperature. However, trees cannot grow in healthy conditions due to the conflicting interests of the many functions and infrastructure in cities. Also time is a limiting factor; before trees are fully grown and can fulfil its various functions (shade, biodiversity, appearance), it takes not only physical space but also time. Alternative interventions, such as a pergola, can help increase urban resilience by reducing the negative impacts of climate change.Pergolas are known, for example, in more southern Europe cities. However, despite the described promising effects of the pergola in documents to reduce heat stress and provide shade, we barely see these structures in the Dutch public space. We all know the pergola as an esthetical piece in the backyard where it provides shade, privacy and contributes to well-being, but they are not widely used in the public realm.Next to that, there are few or no known preconditions for an urban pergola. The functions that an urban pergola can offer go beyond providing shade. The pergola might help reduce noise and pollution, provide a meeting place in a neighbourhood and support biodiversity. Since space is scarce in cities where many different interests come together, we want to explore the potential contribution of an urban pergola to different problems. Therefore, at the Amsterdam University of Applied Sciences, we have worked on an urban pergola as a real 'boundary object' where we bring education, research, municipalities, and entrepreneurs across disciplines and sectors together to discuss the potential of such an object.For this workshop, we would like to show our first results of this interdisciplinary action research and continue answering the question: how can a pergola fit in the Dutch urban area? Therefore, we would like to explore the functions and forms of the urban pergola with stakeholders, such as municipalities, entrepreneurs, citizens, students, and researchers all from different disciplines. The desired outcome of this workshop is a joint proposal for implementing urban pergolas that can meet the versatile needs of cities and thereby make cities more liveable.
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Small urban water bodies, like ponds or canals, are often assumed to cool their surroundings during hot periods, when water bodies remain cooler than air during daytime. However, during the night they may be warmer. Sufficient fetch is required for thermal effects to reach a height of 1–2 m, relevant for humans. In the ‘Really cooling water bodies in cities’ (REALCOOL) project thermal effects of typical Dutch urban water bodies were explored, using ENVI-met 4.1.3. This model version enables users to specify intensity of turbulent mixing and light absorption of the water, offering improved water temperature simulations. Local thermal effects near individual water bodies were assessed as differences in air temperature and Physiological Equivalent Temperature (PET). The simulations suggest that local thermal effects of small water bodies can be considered negligible in design practice. Afternoon air temperatures in surrounding spaces were reduced by typically 0.2 °C and the maximum cooling effect was 0.6 °C. Typical PET reduction was 0.6 °C, with a maximum of 1.9 °C. Night-time warming effects are even smaller. However, the immediate surroundings of small water bodies can become cooler by means of shading from trees, fountains or water mists, and natural ventilation. Such interventions induce favorable changes in daytime PET.
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Het veranderende klimaat is vooral in binnensteden zichtbaar door de hoge mate van verstening die hier te vinden is. Juist op deze plekken zijn er weinig oplossingen voor hittestress en wateroverlast mogelijk, omdat de ruimte boven en onder de grond vaak beperkt is. In dit onderzoek werkten de Hanzehogeschool en The Leaf vof in een consortium met ondernemers en publieke organisaties aan het ontwikkelen van een oplossing voor deze problemen: de Leaf. Een ‘Leaf’ is een groene pergola die meerdere thema’s als hittestress, wateroverlast, biodiversiteit en circulariteit combineert in één oplossing. Het primaire doel van dit onderzoek was om de effectiviteit, haalbaarheid en rendabiliteit van een Leaf in de praktijk te toetsen. Daarvoor is een design thinking aanpak gevolgd, waarin verschillende methoden zijn gebruikt om onderzoeks- en ontwerpstappen te doorlopen. De uiteindelijke ontwerpen zijn uitgewerkt in fysieke prototypes met verschillende karakteristieken die vervolgens op hun effectiviteit zijn getest en vergeleken. Het onderzoek is met een interdisciplinair team van studenten en onderzoekers uitgevoerd, met ondersteuning van verschillende experts uit de praktijk.
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