The responsive city

The key challenges facing our cities

Cities in Europe have undergone many changes during the Covid-19 pandemic. New cycle lanes have appeared where traffic jams used to clog cities' arteries and pollute the air. New plants and trees have been planted where thousands of pedestrians used to endlessly stroll. These small changes are a positive, yet simultaneously reserved response to today’s health and environmental challenges: what we need is a structured response to ensure both human and environmental well-being in the longer term.

The construction and use of the buildings we live and work in currently accounts for 40% of global carbon emissions. By 2050, the European Union has committed to cut these emissions to net zero. At the same time, cities globally will experience a surge in population: two billion people are forecasted to move to urban areas in the same period. By 2030, nearly 9% of the world's population will be living in just 41 megacities (cities with more than 10 million inhabitants). The level of urbanisation in Europe is expected to increase to approximately 80% in 2050. Such an increase in urban population will inevitably be followed by an increase in emissions, unless we change our way of living, moving and working.

Besides the climate crisis, cities are also facing another major challenge: safeguarding urban citizens’ health. The pandemic has highlighted how fragile the health of urban citizens is and has hit hardest in the most thriving global cities. This was not an unexpected event, as other major pandemics had already re-shaped urban environments in the past. Even before the pandemic, poor air quality, water contamination and the lack of green spaces were already recognised as major problems affecting urban dwellers’ health and quality of life.

Climate and health crises in cities are intertwined. A large part of the emissions produced in the use of buildings are due to the end-services needed to ensure adequate levels of indoor environmental quality and hygiene, such as heating a home, cooling and ventilating an office or illuminating a street. On top of this, emissions from transportation are the major pollutants of urban air. This means that tackling the environmental impact of cities without compromising the quality and health of indoor environments in buildings is a key challenge for the well-being of urban populations, especially in the context of a fast-paced urban population growth.

The post-Covid era will see the EU at the forefront of this battle: the proposed recovery package aims to tackle the economic recession caused by Covid-19 by supporting economic investments that enable a digital transition and a green future. This is a great opportunity to re-think and make a shift in the way we design and operate buildings and their components.

The design and operation of cities will need to move from static and unresponsive systems to dynamic, responsive ones. They must be able to vary performance and serve more than one purpose to minimise resource consumption and maximise end-services, adapting in real-time to shifts in demand.

Why shift to a responsive model?

Our way of living, moving and working continuously changes and, accordingly, so do our demands for end-services, spaces and buildings. These demands are therefore intrinsically dynamic and variable. Changes in demand can occur during the same day, such as the need for artificial lighting or transportation; or they can occur seasonally, such as the need for heating and cooling. Other times, our needs change within a larger time-scale, for instance due to disruptive events such as pandemics and environmental calamities, or because of social transformations, such as the increasingly common transition from office-based to smart working. Despite this intrinsic dynamic nature of demands and services, we are still designing and constructing our cities and buildings for one fixed performance in time, one single purpose and, sometimes, even one single use.

The consequences of this mismatch between static design and dynamic demands are visible on several levels. At the city level, we often come across abandoned buildings or unused spaces, which used to be thriving with human activities and now are just left aside, with their embodied energy and carbon unused. Similarly, throughout the Covid-19 pandemic, several office buildings have been left empty for months. These office buildings were not designed to adapt to different functions and occupancy loads in a short time. Even when left unoccupied, it was difficult to switch off their energy consumption without compromising their maintenance and now, if and when smart working remains as a flexible option, we will need to reconsider their use. The lack of recyclability of many manufactured items at the end of their useful life is another example of the same problem: we design buildings thinking at one standard and unchanging use, even if we know that they will not always be able to perform in the required manner.

This lack of a responsive design has an energy and carbon cost, but also a detrimental effect on our well-being and health. Designing for a standard use in time and space also translates into a lack of personalisation, which means that buildings can fail to provide the adequate service at the right time. This is highly evident when we think of the way we design for environmental comfort in buildings, where we use standard models that represent an average need but not the actual need of the occupant. This leads to a waste in energy but also misses opportunities to enhance well-being and prevent health problems such as “sick building syndromes”.

What does a responsive design look like?

Responsive design does not necessarily imply high-tech solutions. The simplest responsive design is the design of an object to serve multiple purposes, which never requires disposal. Many ordinary objects, such as furniture, are designed for multiple purposes. Designing a product so that it can be easily disassembled and reused is an intrinsically responsive attitude. Examples are buildings that are constructed using modular, prefabricated and dry structures. When the component reaches the end of its useful life, a responsive design ensures we can recycle the product. The transition from analogue interfaces to digital touch screens has partially been induced by the same need to allow a flexible re-configuration an infinite number of times. The more complex the function and the end-service one needs to provide, the more complex the technological solution. Responsive design solutions have three main characteristics:

  1. They are sensitive and connected. We need sensors that can read real-time changes in demand and networks to communicate this data.

  2. They have smart controls that can analyse the data and understand patterns and triggers;

  3. They are provided with flexible and variable actuators that can provide a response where and when needed.

The good news is that current advances in sensing technologies, dynamic actuators and automated controls enhanced by Artificial Intelligence (AI), now makes it feasible and cost-effective to design responsive solutions for very complex end-services.

Several cities can already rely on a publicly available wireless network connection and on sensing devices. Local municipalities can get real-time information on many important factors such as air pollution, traffic congestion or occupancy loads. However, cities have the potential to become much more than just instrumented, sensitive and connected spaces. By using AI-enhanced controls, cities can now actually use the data collected by sensors to understand the patterns and the underlying reasons behind these factors. The next step is therefore to become a responsive city, which can also respond effectively to the variation in these important factors, such as increases in electricity consumption, demand for public transport or air pollution. To give an example, in a responsive city we could map the areas with the worst air quality in real time, identify the reasons and patterns, and respond to local surges in pollution with ad-hoc traffic management solutions, such as enforcing a temporary ban on polluting vehicles.

What must the European Union do?

There are still a few obstacles to achieving the required level of responsive behaviour in buildings and cities. Institutions such as the European Union could help address the challenges by improving regulations in the construction sector. Here, three recommendations are proposed:

  1. Regulations and standards need to move from rule-of-thumb and compliance-based design to evidence-based and performance-based design, where the development of responsive performances and automated control decisions are incentivized. When data on real-time performance, weather and occupant preferences was not available, it made sense to establish minimum static benchmark requirements. Now, however, that real-time data on demand and supply is easily attainable, we can set different requirements that are not fixed in time.

  2. Regulators should facilitate the integration of responsive systems across different scales to achieve effective and efficient responsive buildings and cities. For instance, the responsive window and cooling systems must be integrated with the whole building management system. The responsive building must, in turn, be integrated into the district and city scale smart grid. Finally, the single country smart grid must be linked to the European smart grid.

  3. Cities may be getting smarter, but they haven’t changed noticeably, from a user perspective. These responsive solutions must be human-centred. However, there is a lack of interfaces for bridging the users to the AI-enhanced automated controls and understanding their preferences and needs. Buildings need to interact with people, and learn from them. If automated responsive controls are not human-centred, they can’t solve this challenge and they will be sabotaged by building occupants. In the same way, urban citizens will sabotage real-time data collection processes if municipal governments don’t become the guardians of the local data. Local governments must create a framework that empowers urban citizens while also protecting privacy and ensuring that the algorithms used do not discriminate against particular groups of people.

The connected, sensitive, smart city will not solve the current urban climate and health crises if we don’t provide responsive technological solutions that can effectively adapt to shifts in demands at all time scales. More important, is ensuring this is done in a human-centric manner. Ultimately, the lack of understanding of people’s multiple needs, including their privacy protection, is the biggest challenge for responsive technologies to achieve truly clean and efficient solutions. The EU must be at the forefront of human-centred responsive solutions with policies that re-balance our consumptions and demands and allow citizens' well-being to flourish.