The essence of lighting design is layering, or introducing general, task and accent lighting to a space. In a conference room, we might have downlights for general, a pendant over the table for task, wall washers and the presentation zone and accent lighting on artwork.
Introducing controls dramatically increases application flexibility. With a keypad, various visual scenes can be programmed and recalled, as each separately controlled layer responds with different brightness levels.
The lighting choices above would be considered good design, but it requires multiple luminaires of various types with a control function partly dependent on human intervention. Rensselaer Polytechnic Institute (RPI) asked the question, What if a smaller system of lighting equipment could produce the distribution and intensity/spectral control to realize a large number of scenes and wellness recipes automatically enacted based on occupancy?
Let’s look at how such a scenario might work in a building. Imagine entering our hypothetical conference room, only this time it lacks discernible controls and is illuminated by a small number of visible luminaires. The lighting system detects where you are and what tasks you and others are performing and then smoothly adjusts output, spectrum and emission pattern to optimize comfort, productivity and circadian function. For example, a troffer mounted over the table provides a focused, high light level for task work, and then automatically transitions to more diffuse lighting for a meeting.
“Just as the vision of a self-driving car will include an embedded expert driver, we are developing the concept of an embedded lighting designer for autonomous lighting systems,” said Robert Karlicek, professor and director of the Center for Lighting Enabled Systems and Applications (LESA) at RPI. “Our research testbed will explore delivering the ‘right light when and where needed,’ where optimized lighting will require no occupant intervention.”
The concept, which he calls spatially tunable lighting, is being developed by LESA researchers in a joint research effort funded by the Department of Energy. LED manufacturer Lumileds, San Jose, Calif., is providing the beam-steerable, color-tunable light engines, RPI’s LESA and Center for Architecture Science and Ecology are providing the sensing and control algorithms and Dallas-based architectural firm HKS Inc. is providing the design simulations and tools. The completed system will be deployed in LESA’s Smart Conference Room for calibration and performance evaluation during 2022 and will serve as a testbed for continuing development.
The aim is to address three main interior lighting challenges: fixed-profile luminaires cannot dynamically place lighting, only precisely where it’s needed, tracking occupants with passive infrared sensors doesn’t provide accurate activity specifications for added energy savings and the emerging use of color-tunable luminaires makes human control over the systems even harder.
LESA’s goal is more versatile and flexible luminaires that are seamlessly and intelligently responsive. The greater precision and flexibility of steering light beams to deliver the emission profiles of two or more individual fixed-profile luminaires would result in significant potential energy and lighting installation savings. The sensing, Karlicek noted, will provide precise occupancy and traffic information to other services such as HVAC, security, smart power distribution, space use and more, building up to a smart building.
Such a solution will likely be installed similarly as standard lighting, though there’d be little or no room for substitution or relocation of luminaires and sensors. Commissioning would be more intensive, completed prior to installation using virtual reality (VR) software. Post-installation tuning would also be evaluated using VR or augmented reality software. Users may need time to adapt to it.
Certainly, such a solution would impose a higher cost for its advanced capabilities, requiring users to match it with the right applications. The question is: If they build it, will the industry embrace it?
“We see the early adopters being in commercial and healthcare facilities, where activity-driven illumination profiles can save energy, adjust spectral power distributions with defined vertical illuminance profiles and make the occupant data needed to achieve that level of lighting control available to a wider set of ‘sentient building’ operations,” Karlicek said.
While higher-end applications may drive some demand, a more significant driver may be intelligent buildings looking for the right lighting system.
As the LED revolution nears its practical limit of efficacy and achieves mass adoption, the lighting industry is looking ahead to possible scenarios for the future of light. Luminaires that are fully controllable down to beam spread and coupled with advanced sensing networks are developing as a possible contender, and as a player in the future of intelligent buildings.