Most commercial buildings suffer from a fundamental flaw: the building is the focus rather than the people inside of it. The elements that make a building comfortable, such as lighting and heating, ventilation, and air conditioning (HVAC), are often designed to maintain an occupiable space regardless of the occupants. But, advances in technology combined with a rethinking of how buildings operate hold the promise to provide greater localization and personalization of building systems.
The over-conditioning of buildings creates inefficiencies in building operation. Not only is energy wasted, but comfort is sacrificed. Energy management strategies have long strived to address these inefficiencies through better sensing and control to minimize the delivery of energy consuming services when they aren’t needed. Rather than providing lighting and HVAC to an entire floor of an office building, for example, occupancy sensors can be used to turn off lights and reduce HVAC to unoccupied offices.
Overall, buildings have made great strides at reducing energy consumption, driven both through standards such as ASHRAE 90.1 and the desire of building owners and operators to spend less money on energy.
However, these gains have largely overlooked the efficiency that can be achieved through more localized and personalized operation and have instead focused largely on component-level efficiency. Technological and economical limits on making components operate more efficiently are beginning to necessitate a more fundamental change towards control at the system level. Redesigning systems to provide more personalized and localized control can help drive future efficiency.
Indeed, in this respect, lighting systems provide more localized control than other building systems.
In many localities, occupancy sensors are required to shut off lights when no one is present. Fewer requirements exist for the personalization of lighting, such as the dimming and adjustment of lights to meet what a building occupant wants. Such adjustments can provide further efficiency gains.
Similarly, the evolution of HVAC technology to incorporate strategies such as variable air volume (VAV) or variable refrigerant flow (VRF) systems have marked the beginning of a shift toward more localized heating and cooling. Yet, these approaches still fall short. The area around a person where thermal energy is provided can be shrunk, and the temperature setpoint can be adjusted to ensure that the system maintains individual occupant comfort.
Though temperature and comfort are related, they are not synonymous. HVAC systems are designed to temperature because temperature is easier to measure than comfort. The design temperature is set at a level that most people find acceptable. However, this approach introduces more inefficiency as deviations between a design temperature and a comfortable temperature are often corrected by energy-consuming heaters or fans.
However, new research is changing how localized and personalized HVAC systems are, driven by the Advanced Research Projects Agency – Energy (ARPA-E) of the U.S. Department of Energy. Through its Delivering Efficient Local Thermal Amenities (DELTA) program, ARPA-E is providing $30 million to support 11 project teams developing technologies focused on heating or cooling individuals. Funded research includes several textiles that adjust their thermal properties as well as other devices designed to make building occupants more comfortable; these devices range from vents to chairs to robots.
Though DELTA projects represent promising early-stage technology far from commercialization, several other examples of personalization of building systems are already making inroads in commercial buildings.
The most widespread and decidedly low-tech is the occupant comfort survey that is part of the Leadership in Energy & Environmental Design (LEED) building certification program. To achieve this credit, building operators must implement a program to collect feedback on thermal comfort, acoustics, indoor air quality (IAQ), lighting levels, building cleanliness, and other occupant comfort issues. This process is the first step to ensuring individualized comfort, though it may not translate to any energy efficiency.
At least one company has developed a solution to automate the use of comfort information into building automation systems. Building Robotics, an Oakland-based startup, allows occupants to provide direct feedback via a web or smartphone app, which then changes temperature and airflow accordingly. The result, similar to the localization of heating and cooling provided by DELTA projects, creates a robust system to ensure individualized comfort.
Machine learning is applied to optimize energy consumption while maintaining comfort. However, because Building Robotics leverages existing systems, the opportunity to provide more localized control that does not deliver thermal energy where it is not needed is unavailable.
However, the greater challenge, which spans across any approach to introduce localization or personalization to any building system, is communication and integration. As the frame of the user experience in buildings shifts to be more localized—from a building-level, to a room-level, and ultimately to a human-level—the building system communication network needs to change to support a more complex flow of information. A more localized and personalized approach to the control of building systems requires a vast expansion of the number of devices on a network and coordination between them in order to optimize energy and comfort.
