21 jun StudentTalks: Thaisa Martins about Urban Thermal Comfort
Thaisa is one of the students we had good contacts with during the writing of her thesis, she is a student at the Faculty of Spatial Sciences and she approached us, because she wanted to talk with people from the municipality about her subject. We introduced her to the right people at the municipality and she even got to present her research at one of the Next City seminars at DOT. Here, she talked about climate change and the effects it has on our cities and also presented a model she developed called Urban Thermal Comfort. Read more about the research in this episode of StudentTalks:
Urban Thermal Comfort: The influence of urban design on outdoor temperatures and thermal comfort
In a broad perspective, urban thermal comfort (UTC) means a satisfaction with the temperature in outdoors spaces. This thermal comfort is, therefore, directly influenced by the microclimate and the urban design. This is because the configurations and materials we use in the urban landscape interact with the thermal environment, therefore influencing outdoor temperatures. Public spaces which are thermally comfortable are more attractive and stimulate space use and urban activities.
Thermal comfort is a topic very much explored in the indoor environment. After all, we spend around 80% of our lives indoors, so it is understandable that the longstanding concern is to create homes and working spaces with comfortable temperatures. But why is thermal comfort not yet a concern for outdoor environments? The urban space is our backyard; cities are for people to use and experience, so promoting comfort should be a priority. And within the varied types of comfort (e.g. visual, acoustic) the thermal is the one that most influences our satisfaction with the environment. Climate change and urbanization are, in a global and local scale, enhancing the urban heat: increasing outdoor temperatures diverge cities from the path towards healthy ageing and healthy cities, making public spaces unattractive and triggering space disuse. But how can we avoid this situation?
Indeed, at our homes we can turn on our heater or air conditioning, while the outdoor space is out of one’s control. However, we can create a landscape in our city which copes with the microclimate for promoting Urban Thermal Comfort. The forms in the landscape (e.g. open or semi-enclosed areas, high or shallow buildings) influence shading and wind throughout the streets; landscape materials, according to their properties, retain less or more heat; green and water are capable of promoting a cooling effect; urban design elements (e.g. shading elements and wind buffers) are strategic elements for promoting UTC. The Damsterplein (in the city of Groningen), for instance, is a completely paved open square, with scarce greenery, no water body, scarce shading, scarce furniture and “cold colors” in the landscape (Figure 1).
On one hand, this means that, in very cold days, the cold pavement and the lack of wind buffers in the open square where wind converges tend to trigger a cold stress. On the other hand, in very hot days, the paved ground retains more heat and the lack of shading increases the air temperature, contributing to a heat stress (Figure 2). Such stress can aggravate delicate health conditions (e.g. heart problems), being a concern to elderly people. UTC strategies for the Damsterplein could involve the use of more greenery in connection with leisure equipment, being a shallow water body also an alternative for a more efficient cooling effect (Figures 3-5). Because there is a parking garage underneath the square, the use of robust trees is not feasible. However, the existing set of trees can be extended, or even artistic elements could be inserted, for providing more shading on the square.
Developing UTC strategies requires creativity in the urban design. Over time, the urban landscape must be flexible and managed in a way that thermal comfort is continuously promoted through seasonal and long-term temperature changes. Importantly, the approach to UTC in urban design and planning practice requires urban policies to provide the basis and encourage UTC awareness and implementation. Framing this relationship between urban design and microclimate, planning practice and urban policies, a conceptual model was developed for assisting urban planners, designer and decision makers in promoting UTC (Figure 6).
In this model, there are four key dimensions: (1) inclusion (how to include UTC in urban policies and urban design?); (2) implementation (what mechanisms are important for implementing UTC?); (3) design (what features in urban design which influence UTC?); (4) adaptability (how to manage urban design over time for continuously promote UTC?). This framework suggests key abstract and practical aspects to urban policies and urban design for promoting UTC. The conceptual model of UTC strategies, as a tool for urban policies and urban design, can contribute for creating more comfortable and healthier cities. This means enhancing urban life by means of prioritizing wellbeing and liveability for the people.