Interviews + Opinion, Research

RPI’s Bob Karlicek on Spatially Tunable Lighting

For an upcoming article in Electrical Contractor Magazine, I recently had the opportunity to interview Bob Karlicek, Ph.D., Professor of Electrical, Computer and Systems Engineering at Rensselaer Polytechnic Institute, Director of the Center for Lighting Enabled Systems and Applications, co-Director of the Energy, Built Environment and Smart Systems Institute at Rensselaer. The topic: spatially tunable lighting, which LightNOW first reported on here. Transcript follows.

DiLouie: What is spatially tunable lighting?

Karlicek: Spatially tunable lighting creates the ability to digitally alter the light emitting properties of a luminaire directionally and spectrally, to customize lighting profiles for given tasks. For example, imagine a troffer that could provide task lighting at a table, and then digitally adapt for more diffuse lighting for a meeting. Furthermore, the lighting system would know which tasks needed which lighting profiles, and digitally adjust the profile as needed.

DiLouie: What is the rationale behind its development? What is the market need, and what are the benefits?

Karlicek: The rationale is twofold: energy savings by providing only the right amount of illumination for a given occupancy scene, and lighting installation cost savings by installing a beam steerable light fixture that can deliver the beam profiles of two or more individual fixed profile light fixtures.

DiLouie: LESA is currently developing a solution with Lumileds, CASE, and HKS. What is the research goal?

Karlicek: The research goal of this DOE BTO funded project is to build a testbed to validate the energy savings and human factors considerations (circadian lighting, comfort with adaptive lighting) with a lighting system that can operate autonomously, sensing the occupant positions and estimating the type of activity, and then delivering only the required amount of illumination with the desired beam profile and spectral characteristics for the task at hand.

DiLouie: What’s different between this type of lighting solution and the most advanced solutions currently offered?

Karlicek: First and foremost, there aren’t many digitally steerable lighting solutions on the market and those that are use motors or have limited beam steering capability. Second, lighting control systems still suffer from “human in the loop” challenges. As tunable lighting for wellness gets more complicated, occupant control will require too much knowledge for mere mortals to be able to operate them properly. Our research testbed will explore delivering the “right light when and where needed,” where optimized lighting will require no occupant intervention.

DiLouie: If realized, SCULPT will present a “sentient” lighting system that is intuitively responsive to occupants without direct intervention. Is similar research being undertaken for other systems such as HVAC, which would allow a “sentient” building?

Karlicek: That would be the goal of this program, adding lighting to the list of building systems that operate autonomously. Even more importantly, the sensing systems needed for the SCULPT lighting will provide precise occupancy and activity information to other building services like HVAC, security, smart power distribution, space utilization, and so on, making broader building sentience more attainable.

DiLouie: What applications do you see as early adopters for this type of solution?

Karlicek: 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.

DiLouie: Do you see adoption ultimately being driven primarily by lighting applications (which can become part of smart buildings) or by overall smart buildings (which will pull lighting into it)?

Karlicek: This is a great question, and in reality, we believe that the smart building operations would benefit the most and provide the best return on investment, and steerable, tunable lighting would be an important fringe benefit. It will really be the high fidelity, privacy preserving occupant activity estimation capabilities for the sentient building that will drive adoption.

DiLouie: Imagining a future product, what would be different for electrical contractors? Would this be more or less difficult to specify, install, and commission? Would there be any new opportunities?

Karlicek: We expect that specifications would be set out by architects and lighting designers, and there would be no room for substitution of either the specified fixtures and their location, or the distributed sensor networks that enable autonomous operation. The commissioning operation would likely be different, with simulations and testing having been performed ahead of installation using virtual reality (VR) software, with field changes also being evaluated using VR. Commissioning post installation would be performed as it is now, but would be aided with augmented reality (AR) systems.

DiLouie: What would a typical user experience look like under this type of solution?

Karlicek: Initially, the users might need to get used to lighting that changes as they move and change their activities. We are curious about what user acceptance of spatially and spectrally adaptive lighting will look like. While we are not currently looking to build machine learning and artificial intelligence into the control system, future versions of SCULPT would likely incorporate those capabilities, so the illumination adaptability would get more comfortable for the user over time.

DiLouie: If you could tell the entire electrical industry only one thing about spatially tunable lighting, what would it be?

Karlicek: LEDs are continuing to unleash a broad range of new lighting technologies that will require continuous training of the experts that specify, install and maintain lighting systems. We are just at the tip of the iceberg.

DiLouie: Is there anything else that you’d like to add about this topic?

Karlicek: If we can have autonomous, self-driving cars and trucks, we can certainly achieve autonomous, high quality spatially and spectrally adjustable lighting that knows what lighting is needed where and when. That is what we aim to show.

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Craig DiLouie


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