PNNL

The days are growing shorter, and some of us are beginning to decorate for the holidays.

At this time of year, it's easy to have a greater appreciation for light. But, for researchers at the Department of Energy's Pacific Northwest National Laboratory, the quest for advanced, efficient lighting technologies is a year-round pursuit.

With more than 20 years of work in this area, PNNL has one of the strongest lighting research capabilities in the country. On behalf of DOE's Building Technologies Office, our scientists and engineers conduct laboratory and field studies that influence the development of new lighting technologies. Their research also is illuminating light-related phenomena, including color and vision science.

At PNNL's Lighting Metrology Laboratory, researchers use a spherical chamber 2 meters in diameter to gather photometric data — verifying the light output and spectral characteristics of light bulbs and other lighting products.

This nationally accredited test laboratory also evaluates how lighting products respond to high-temperature conditions and how light performance changes over time. For example, years ago, our researchers tested early light-emitting diodes (LEDs) for flicker, collecting data that shaped industry standards and, more recently, validated the accuracy of today's flicker meters.

Today, researchers at PNNL's new Connected Lighting Test Bed in Portland are studying innovative approaches to lights that do more than just brighten a room. These "connected lighting systems" integrate sensors and information technologies with lighting to create intelligent devices that can automatically adjust color and light levels, sense when people are present, monitor energy usage in real time, and communicate with building management systems.

PNNL is testing the potential for connected lighting systems to offer higher quality, more responsive and more efficient lighting, as well as exploring how they could become a platform for new products. For example, lights could be used to improve space utilization, report maintenance needs and track physical assets and inventory. And because these lights are connected to the internet and other networks, PNNL also assesses cybersecurity vulnerabilities and how to address them.

Beyond the lab, PNNL researchers develop testing methodologies and evaluate lighting technologies in real-world settings. PNNL led the development of a new way to test and measure the color rendering capabilities of light sources, such as LEDs, that can be tuned to different points on the spectrum, something that earlier industry standards failed to capture.

Working from a common standard opens new possibilities in lighting science, including ways to evaluate people's preferences and the physiological effects of lighting. In one study, people were asked to evaluate how colorful objects appeared in 50 different LED lighting scenes. Most people like colors — especially the reds in food — to appear vibrant and saturated, like they do in bright daylight.

With results like these and the help of new standards, future LED lights can be tuned to maximize color quality, efficiency and efficacy.

In another study at Swedish Hospital's Behavioral Health Unit in Seattle, PNNL evaluated lighting designed to reduce disorientation and sleep disruption among patients.

During facility renovation, architects used their ability to vary the intensity and spectrum of LEDs to design a system that emulates the way sunlight changes throughout the day from sunrise to sunset. The varying light provides patients visual cues about whether they should be waking, up and about, or settling down for the night. PNNL scientists measured the light output and interviewed the staff to analyze energy use and interpret the data related to physiological effects.

So the next time you turn on a light, think about how far we have come from Edison's early incandescent bulbs — and know that PNNL researchers are hard at work on the lighting systems of the future.

And as the holiday season approaches, our wish is that your days may be both merry and bright.