Office of the Vice President for Global Communications

Friday, March 11, 2011

New wireless lighting control system to save energy, costs

The university will test an energy-savings lighting technology that also enhances safety and visibility with a pilot project in the Hill Street parking structure adjacent to the Stephen M. Ross School of Business.


The new LimeLight system, developed by a Michigan company, makes use of a sophisticated computerized management system that allows individual lights to be turned off and on by program settings, motion sensors and photocells.

"We are thrilled to introduce this new breed of lighting system to the campus community," says Steve Dolan, executive director of Parking & Transportation Services. "The LimeLight system automatically reacts to the lighting needs in any given location to enhance both the safety and energy efficiency of our structures."

The system works like it would for a homeowner, where a motion detector turns on an outside light as the homeowner's car approaches the garage.

In this case, the 231 lighting fixtures in the 473-space parking structure can be controlled in several ways.

Lights can be controlled through computer programming. Each lighting fixture is assigned to a lighting group and the typical schedule for those lights is set based on the facility's typical use patterns.

Motion sensors also control the lighting fixtures. When motion is detected, the sensors override the programming to activate groups of lights.

For example, once turned off for the night, the lights would turn on as an employee, working late, starts walking toward his or her vehicle. Lights would continue to illuminate the path of the vehicle as it exits the darkened parking structure. The lights would turn off after 15 minutes of inactivity.

Photocells sense ambient lighting levels and activate alternate programs that turn off individual lamps. This is known as light harvesting.

"The sensors will detect when natural light is available and activate other programming that selectively turns off lights," says Diane DeLaTorre, associate director for parking operations and maintenance at PTS. "When it becomes darker, normal programming resumes. This feature will save energy and the life expectancy of the lamps."

The Hill Street location was selected as the first test site because the lighting system there was obsolete. The old lighting fixtures used 250 watts compared with the new technology, which uses a 102-watt fluorescent fixture.

"The old fixtures produced insufficient light levels (by current standards), resulting in dark areas, and were operationally inefficient. With LimeLight we were able to achieve improved lighting and also gain significant operational efficiency," DeLaTorre says.

The new pilot project is consistent with the university's overall efforts to reduce energy. Earlier this year, the university announced that its Planet Blue operations team building program decreased overall energy use on campus by 14 percent — avoiding $5.2 million in costs — in 67 buildings on the Ann Arbor campus during the last year.

"Our Parking and Transportation team is very focused on finding ways to reduce operating costs in all aspects of our operation. Depending on how aggressive we are with using the features of the LimeLight system, we can expect energy savings associated with running the lights of up to 40 percent. It's a great example of how using technology can help PTS with its fiduciary and sustainable responsibilities," Dolen says.

The total cost of the project was $550,000. University officials say the energy-savings technology cost approximately $100,000, and should pay for itself in two to three years.

The university will review the success of the pilot in coming months to determine whether to convert other structures to the energy-saving lighting system.