Written by Gregory Miller
Why do we need Smart Cities?
By 2050, there will be around 9 billion people on earth, 67% of whom will live in growing urban areas.
Worryingly from a sustainability perspective, urban areas have disproportionately large ecological footprints and the urbanization required to house growing urban populations is hugely resource-intensive. In fact, the building sector, with its reliance on energy-intensive materials such as concrete and steel, uses around 40% of global primary energy consumption and is responsible for around 36% of total CO2 emissions.
The ecological footprint of cities is therefore huge, and a growing environmental problem. To counter this problem, the power of technology is shaping the agenda in direct response and by 2021, the smart building technology sector is forecasted to be worth $US 24.73 billion. Technology, after all, can not only fundamentally change the urban landscape, but also the way we behave within it. In the future, many hope technology will also change the way cities ‘behave’. And this, in terms of sustainability, is the key to smart cities. In the future, schools, hospitals, museums, cars, buildings, farms and virtually everything in between may operate remotely and responsively in a connected system that maximizes efficiency.
So, are Smart Cities the Answer?
Smart technology is seen by many to be key for a transition to a low-carbon economy and the solution to many of our environmental problems – such as energy inefficiency, congestion, food scarcity, and urban population growth. At the heart of it is the Internet of Things (IoT) and the ability of everything to connect.
In more specific terms, IoT relates to internet connectivity and it considered revolutionary precisely because it involves connectivity on a level that is unimaginable until now. It enables not only machines to be connected, but also objects, people and even living organisms. This means almost everything could be made ‘smart’, from manufacturing processes to the growing of food (and everything in between). Not only that, but connectivity is not dependent on size. In fact, sensors so small they are invisible to the naked eye could make access to the internet virtually limitless in scope, scale and reach.
Despite the potential, smart technology in cities remains undeveloped, so data on the effectiveness of schemes relating to efficiency gains is limited. However, in Singapore, the Smart Nation program, consisting of technologies to reduce energy consumption, has begun monitoring consumers and collecting data on both domestic and corporate buildings. It is claimed by the HBD (Housing and Development Board) that these technologies – including smart fans, solar power, water-recycling smart lighting will generate energy savings of around 40% (in terms of lighting). Homes will also be digitally equipped with sensors and motion detectors and in a joint study by the HDB and Energy Market Authority Singapore (EMA) showed a reduction of energy consumption by 20% after implementing the Home Energy Management System (HEMS).
Smart technology is being used in many cities around the world such as Singapore, Amsterdam, and Barcelona. In Amsterdam for example, a smart city collective now has nearly 7,000 members and organizes events, projects such as City-zen, school visits, etc. City-zen is a joint initiative by Amsterdam and Grenoble and the new urban energy project with projects including residential refits, heating and cooling, monitoring, and smart grids. With 20 innovations, they aim to save 35,000 tonnes of CO2 per year. Examples of the smart technologies they are using include:
- Smart Electric Thermal Storage (SETS) which is being used to replace traditional night storage heaters in 1250 homes across Ireland, Germany, and Latvia. SETS can be designed for smart grid installation and is an easy potential replacement technology for the current 14 million homes in the EU that are electrically heated with standard heaters. SETS have been shown to offer:
- 20% efficiency gain compared to night storage heaters
- Increased Comfort – more control over target temperature and less heat leakage
- VivaCité tool (multi-energy monitoring interface) in the Mistral Program in Grenoble, which is incorporating smart grid connectivity into the retrofit of 3 towers built in 1967. Inhabitants will ‘co-construct their own well-being indicators’ and benefit from controlled district heat recovery ventilation. The stated energy savings deliverable: 64 kWhEP/year.m2 (-50%)
HVAC (heating, ventilation and air conditioning) typically form the bulk of a building’s energy needs and in industrial buildings especially, the way HVAC systems are operated significantly impact the energy efficiency of the building. Currently, all buildings are said to waste at least 10% of their energy. Optimizing HVAC equipment is, therefore, a sustainability priority and can be achieved by applying methods such as dynamic programming and genetic algorithm (GA) optimization to maximize thermal comfort and minimize cost. In one study of the cost-effectiveness of this approach, the use of energy from PV and storage was assessed by controlling the indoor temperature measurements restricted in low, medium, and high HVAC operating modes. Demand response was used in conjunction with a linear model of temperature evolution, developed by correlating past values of temperature with HVAC equipment turned on/off at instances in time. The study proved that costs could be reduced with respect to a ‘standard’ thermostat use in two different ToU pricing schemes.
Demand response can also use a model predictive control framework to determine optimal control profiles of HVAC systems. This approach, which has also been studied under controlled conditions, uses a non-linear autoregressive neural network configuration which models the thermal behavior of a building zone, simulating HVAC control strategies in line with demand response signal. The approach in question considered existing on-site energy generation and storage systems with night set-up, demand-limiting and pre-cooling HVAC control strategies and formed the optimal control problem as a MINLP (mixed-integer non-linear problem). The levels for zone temperature and power consumption were then able to be reliably predicted – leading to the following cost savings: 14.25% to 15.26% for demand-limiting and optimal control (without energy generation and storage) and 30.95% for optimal control (when combined with energy generation and storage).
Smart cities are based on the premise that everything benefits from being connected – the idea that the more ‘smart’ it becomes, the more sustainable it can be (energy-efficient) and the happier residents (or visitors/workers) will become. Demand response is an example of this – it changes the way buildings consume power in a way that embraces the connectivity paradigm of the smart city. Consumption of power can be remotely controlled by the real-time exchange of data, enabling reduced peak loads (by spreading demand), better integration of unpredictable renewable energy sources, and improved smart storage and distribution of excess power within smart grids. Demand response utilizes technology like smart meters and enables smart consumption of power, e.g. maximizing use during peak renewable production. Interestingly, however, this is not necessarily about reducing energy use per se. Instead, optimized systems could better be described as those which optimize how and where electricity is produced and how it is used or stored.
Smart buildings may rise from scratch, or be redeveloped. Torre Europa in Madrid is an example of just such a building. Recently reformed, it now stands as one of the world’s smartest tall buildings. Its control center analyses data from all areas of each floor and monitors occupancy levels in real-time. This enables not only heating or air conditioning to be optimized, but also cleaning and maintenance. Also controlled are the 14 elevators and all lighting. The result has been significant gains in efficiency, recognized by the Council of Tall Buildings and Urban Habitat (CTBUH) which awarded Torre Europa the 2019 award for the best high-rise building renovation.
Smart skyscrapers like Torre Europa are iconic buildings which shape the identity of entire countries. However, they can be extremely resource-intensive, so to achieve sustainability goals, their construction and planning also need to become significantly more efficient. Digitized planning enables this transition. An example is Dubai. Urban planners were brought into the city with the aim of attracting new talent to the city. Digitized planning enabled the planners to divide the city into zones of shared interests or features, such as Dubai for banking, Dubai for health and medical services, Dubai for leisure, and so on. Each of these sectors was ‘branded’ within an infrastructure designed around the needs of professionals and companies operating in their sector of interest.
Digitized planning involves smart model-based processes which enable cities to be envisioned in a virtual, real-time space. It extends the application of smart technology to the actual design, planning, and construction of extended and connected urban environments and it can, therefore, turn localized planning events into smarter and more integrated process in which city-wide or even nationwide resources are pooled. And this, in a nutshell, encapsulates the potential of smart technology to radically transform the urban landscape; it is the promise of a seamless transition from both the top-down and the bottom-up of a digitized network of complete connectivity which makes decisions in a way that maximizes efficient use of resources and minimizes environmental impacts.
Gregory Miller is a writer with DO Supply (https://www.dosupply.com) who covers Robotics, Artificial Intelligence and Automation. When not writing, he enjoys hiking, rock climbing and opining about the virtues of coffee.
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