Climate Sensitive Urban Design Using A Feedback Loop
PYRO
A CLIMATE BASED DESIGN ASSISTANT
Outdoor Thermal Comfort is one of the crucial factors that determines the perceived quality of urban open spaces for the sustainable design of cities (Emmanuel, 2016). Since the last decade, comfort is being increasingly used in conjunction with health to define well-being in the built environment. Extreme urban temperature, which is a direct impact of the resilience of built form against climate, tends to increase energy consumption owing to a high rate of heating and cooling energy driven processing. This stresses on the importance of regulating the effects of built form on the environment.
Since built form has a direct impact on the quality of outdoor open spaces, favorable urban microclimate modification or conservation of the existing climatic conditions can be achieved by context appropriate, climate-sensitive design. Unlike the one glove fits all design strategy, the current scenario calls for a more nuanced urban form finding process where designers and planners instead of being providers become facilitators, ceding design control and allowing a larger audience to participate in the design process. For this, I developed an interactive design widget “PYRO” that uses a fluid performance feedback based on climate simulation metrics to allow users to determine the best possible design solution for different contexts.
PYRO in Mumbai
Performance of Form
I conducted a study to analyzing the impact of built form on its context and consequently propose an alternate urban design method using PYRO. As part of the study I picked an affluent residential neighborhood in suburban Mumbai. The precinct has several gated housing societies and private open spaces. Unfortunately, the street pavements and a nearby beach are the only available open spaces that are truly public in nature. This issue of inequitable distribution of inhabitable outdoor spaces was a cause of concern and needed immediate design/planning solution.
Through my study, I propose a scenario where a reconfiguration of built form in the precinct opens up pockets of public spaces with controlled microclimates. These spaces are intertwined with the urban fabric in a way to create a more inclusive neighborhood. These spaces will be connected by urban alleys and thoroughfares, thus, engendering an open space network within the precinct.
To test this model, I selected a city block in the heart of the precinct. The site supported programs such as a school, a junior college, a multipurpose hall and a private event space. The idea was to redevelop the site by reconfiguring the massing in such a way that it opened up pockets of inhabitable public spaces. PYRO would be used to iterate between multiple design solutions and test its performance for this context.
Climate Analysis
Mumbai experiences a warm and wet climate according to the Koppen Geiger climate classification. Along with summer and winter seasons spanning four months each, the city experiences a stark monsoon season from June to September which is marked by warm temperatures and high humidity. In such a climate, vibrant and comfortable outdoor spaces are important resources which, I believe, will support the city in its test against the threat of climate change.
UTCI (Universal Thermal Climate Index), which determines perceived temperature and the corresponding thermal stress was used as the main metric to gauge outdoor thermal comfort. Four categories were create based on the presence or absence of solar and wind exposure. These categories were tested against a target UTCI temperature of 26°C for the summer season (Mar-Sept) and 23°C for the winter season (Oct-Feb) for optimal thermal comfort and consequently, the best strategy for all hours of a year was suggested in order to assist the designer/planner.
This data was then used in a combined sun path and wind rose diagram to get direction specific design strategies for the intervention. This would help in determining the building orientation and height range.
The new open spaces would be used as school playgrounds, event spaces and public plazas; supporting activities such as running, exercising, walking and sitting. However, due to different operating hours of these programs and hence, corresponding activities, the ideal location for these was identified based on the simulations. For example, energy intensive activities like running and exercising should be avoided in spaces identified to have a high probability of thermal stress.
Design Logic
The proposal seeks to redevelop the plot, retaining some of the existing programs, while trying to explore opportunities to integrate public spaces like public plazas, urban alleys and thoroughfares with these private programs.
The design logic was to allow maximum design flexibility by using simple drawing tools. Basic design elements like lines are used to define urban alleys and thoroughfares, circles are used to define public plazas and a direction vector is used to represent the wind direction. Users could create open spaces and control the amount of solar and wind exposure these spaces experienced by means of altering the built form orientation and height. Area and climate simulation metrics would constantly dictate design and compare it to the existing design. Users would also be able to compare multiple design options to choose the most viable solution for this context.
Climate Simulation Feedback Loop
Climate simulations were integrated in PYRO’s user interface so that users could test the performance of their design through a feedback loop. The open spaces were tested against the total sunlight hours received and solar exposure. The sky view percentage for building facades was also measured to check for dimly lit spaces. This would consequently help users measure the amount of diffused light entering the building through the façade which in turn would help in calculating the daylight factor, a metric used to design indoor spaces based on daylighting.
To test the effect of wind exposure on the site, wind simulations from INFRARED was used. It is simulation software developed by the City Intelligence Lab which uses next-generation AI driven platforms to carry out extremely complex wind simulations. As a result it indicated the type of activities that could be performed in different parts of the site.
A New Design Process
I believe that a successful design considers climate and other context driven factors at an early design stage rather than squeezing it in as an afterthought to render the design “contextual”. A climate based feedback loop lends users flexibility in design and allows them to explore multiple design options and test them against different performance metrics at an early stage. Using PYRO, the status quo design process of achieving the perfect design, an aftermath of the “starchitects’” whim, is replaced by an egalitarian process which allows freedom of exploration.
