Lighting the Way for the Future

Did you forget to turn out the light in your office when you left for lunch yesterday? What about leaving the light on in the hall as you rushed out of the house this morning? No big deal, right? Well Bryan Hilson, an undergraduate who worked in the Hybrid Solar Lighting Group at Oak Ridge National Laboratory (ORNL) might disagree. Hilson, who attends Central Piedmont Community College in Charlotte, N.C., spent the summer conducting solar lighting research at ORNL through the Department of Energy’s (DOE) Higher Education Research Experience Program.

Bryan Hilson inspects a large-core optical fiber that—in new hybrid solar lighting systems—will carry concentrated sunlight into buildings.

Lighting in residential and commercial buildings consumes close to one-fifth of all electricity used in the U.S. each year. Hybrid Solar Lighting Group research is aimed at developing and commercializing new hybrid solar lighting systems that more than double the efficiency and affordability of solar energy in commercial buildings by simultaneously separating and using different portions of the solar energy spectrum for different purposes like lighting and power generation.

In other words, the group is researching how to use sunlight to more efficiently light buildings. Their research has shown that in commercial buildings lighting consumes more electric energy than any other use, accounting for more than a third of all electricity consumed for commercial use in the U.S. Lighting consumes so much electricity in part because it is inefficient, converting only 25 percent of electricity used into light. The other 75 percent of this energy is used to generate the illuminating heat that increases the need for air-conditioning.

The hybrid solar lighting system uses roof-mounted concentrators to collect and separate the visible and infrared portions of sunlight. “You essentially pump sunlight inside,” said Hilson. The visible portion is distributed through fiber optic cables to hybrid luminaries, fixtures that contain electric lamps and fiber optics for sunlight distribution. The infrared radiation portion of the sunlight is directed to a cell that converts this radiation into electricity that can be directed to other uses in the building.

Hilson has focused a lot of his research on the hybrid luminaire control system. “Basically, we needed to develop a way to control the artificial light in a hybrid system, so that when the sun is shining the artificial lights are dim and when skies are gray the artificial lights are bright,” he explained. He has also been working on understanding the sunlight collectors and the solar tracking hardware and software systems.

Although Hilson did not consider any day a “typical” day on the job, throughout the summer he practiced all the steps of the scientific method—researching background information on light systems and electronic controls, proposing ideas based on that research, experimenting with those ideas, evaluating the results, and drawing conclusions.

Hilson worked at ORNL for a 22-week Summer Higher Education Research Experience (HERE) under his mentor, Duncan Earl, and project lead, Jeff Muhs. Hilson has also participated at ORNL in the 10-week Community College Institute program sponsored by DOE’s Office of Science. These programs, administered by ORISE, are designed to complement academic programs by utilizing the unique resources of ORNL to enhance science, mathematics, engineering, and technology education, and encourage careers in science and technology while at the same time contributing to the Lab’s mission.

Hilson definitely agrees that his experiences shaped his career goals. “My interest was electronics engineering technology until I entered this program. Now I know that electronics engineering technology is really just implementation, and electrical engineering is more of the research and design of systems, which is what I want to do. I would not have known this had I not gone through these programs.”