Smart Buildings: When Sustainability Meets Information Technology

Dr. Elie Azar
Assistant Professor at Masdar Institute
Abu Dhabi, United Arab Emirates

It is believed that people spend 80 to 90 percent of their life in buildings. As a result, buildings can have a major impact on people’s health, wellbeing, happiness, and productivity. For instance, a healthy work environment has shown to reduce employee’s health problems, reduce absenteeism and turnover, increase work performance, and reduce operation costs for employers.

In parallel, buildings are major contributors to the high energy consumption and carbon emission levels that we are witnessing today. On average, the building sector accounts for 30 to 40 percent of the energy demand of different countries. This ratio exceeds 60 percent for countries such as the United Arab Emirates (UAE), where extreme weather conditions dictate high air conditioning loads.

Multi-layered challenges

In recent years, there have major advancements in building technologies, energy-efficient designs, and green building certifications and labeling programs. In theory, the goal of such initiatives is to optimize building performance along the three pillars of the triple bottom line. In practice, buildings consistently consume more energy than they are designed to, and do not necessarily provide optimal working environment for their occupants. Recent studies in the United States (US) show that even LEED-certified buildings are failing to truly achieve the promised building operation efficiency (LEED: Leadership in Energy and Environmental Design).

A closer evaluation of the performance of buildings highlight common and major inefficiencies at various levels.

At a micro “occupant” level, actions taken by building occupants can have a major impact on the energy consumed by the building. For instance, setting the thermostat temperature at 22˚C instead of 24˚C can increase energy consumption level by more than 10 percent. As another example, a recent study shows that more than half of office equipment are typically left running at night in US commercial buildings. In summary, people actions currently contribute to the common underperformance of buildings, motivating the need for more responsible occupancy energy use patterns.

At a meso “building systems” level, important inefficiencies are also observed in the management and control of different building systems. Here again, studies indicate that facility managers oftentimes fail to monitor, coordinate, and optimize the performance of building systems such as HVAC (Heating, Ventilation, and Air Conditioning).

Clashes and faults in these systems are very common even in green buildings, where advanced and hightech systems might become complex to manage.

At a macro “city” level, a building is seen as an element of a large infrastructure of buildings such as in a community or city. Optimizing the operation of the building stock becomes therefore important, especially to match energy demand with supply from various sources, including renewables such as solar and wind energy. These sources are intermittent by nature, further complicating the task of synchronizing demand with supply.

Smart Buildings

Recent advancements in data gathering, analysis, and communications present new opportunities for the design of more intelligent, or “smarter” buildings.

During operation, smart buildings use information technology to (1) connect and synchronize building sub-systems that typically operate independently, (2) communicate and engage with occupants, and (3) connect and respond to demand-side management strategies through smart grids.

Level 1: Building energy management and automation

Modern buildings have complex electrical and mechanical systems that require a high level of management, maintenance, and control. Furthermore, these systems need to efficiently communicate and work together for optimal building performance. For instance, an air conditioning system can be optimized by (1) obtaining weather data from outdoor sensors to determine how much outside fresh air to use, and (2) by learning about occupancy schedules and movements to reduce the cooling of unoccupied building areas. A Building Management System (BMS), also referred to as Building Automation System (BAS), is a computer-based system that can be used to monitor and control various building systems. It consists of hardware components such as sensors, which collect real-time data from the building, and software programs that analyze this data and translate it to controllers that execute actions for different building systems. The exchange of information is typically achieved through wired and/or wireless communication networks, which can centralize relevant building information and controls in one location for easy access by facility managers. This also facilitates the process of detecting and fixing potential faults in building systems.

Level 2: People

A smart building should engage its occupants to achieve two important goals. The first is to raise occupants’ awareness of energy saving and provide them with the right information to take responsible actions. The second goal is to provide them with a certain level of control over their built environment conditions, helping them maximize their comfort, wellbeing, and productivity.

Starting with the first goal, providing occupants with feedback about their individual and/or group consumption levels has shown to significantly increase sustainability awareness. Typically, a large number of occupants are not aware of the impact of their action on building performance. By communicating such information to them, and coupling it with energy conservation tips and practices, significant amounts of energy can be saved. Furthermore, feedback about the consumption of peers or friends has proven to be the most effective, generating certain social norms that encourage participation and energy savings. In practice, feedback can be provided to occupants from information obtained from a BMS or BAS. This gridsinformation can be communicated by paper (e.g. reports or brochures), by email, or through a real-time interface such as the one shown in the figure below.

As for the second goal, studies indicate that occupants who control their environmental conditions are more comfortable, happier at their jobs, and more productive. Consequently, smart buildings should allow occupants to control some or most of their environmental conditions (e.g. thermal conditions or lighting levels). Furthermore, technologies such as smart thermostats can learn from the historical preferences of occupants, and customize conditions to their specific needs.

Level 3: Smart gridsinformation

The mission of a smart building goes beyond optimizing its individual performance. It expands to optimizing the performance of a group or stock of buildings such as in a city.

This has been made possible due to advancements in smart metering and smart grid technologies. A smart grid is a network of communications, control/automation, and power technologies, characterized by two-way flows of electricity and information between buildings and utility companies. It provides utility companies with real-time data about the energy demand of buildings (mainly from smart meters), and allows them to communicate back strategies and incentives to the building stock to manage total energy demand and time of use.

One such demand-side management strategy is the time-of-use tariff, where electricity costs are raised during peak demand hours. This motivates buildings and companies to shift some of their energy consumption to off-peak hours, helping utilities reduce peak-load generation, which is typically costly and can require expanding existing energy production capacities.

In general, demand-side management strategies have gained significant interest in the industry, especially with the introduction of renewables in the energy mix. Solar and wind energy for instance are highly intermittent, making the task of matching energy supply to demand a very challenging task for utility companies. Thus, detailed monitoring by smart meters, coupled with communication to and from utilities, allows utilities to better control and distribute demand, optimizing the overall performance of the energy infrastructure.

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