The most recent targets of the university's search for greater energy efficiency are campus parking structures and lots.
"Our parking facilities are, for the most part, unoccupied, and the lights are on 24/7," Phillips says. "We thought that would offer a good opportunity to take advantage of LED technology and incorporate into that lighting controls."
The previous lighting system featuring 150-watt high-pressure sodium lamps had not presented problems but instead simply represented an opportunity, she says, adding, "We just wanted to not have the lights on all the time. We did a survey and found that our parking facilities are only occupied about 3-5 percent of the time, so it's a huge opportunity to either turn the lights off or lower the light level when they're unoccupied. High-pressure sodium is not a source that can be turned on and off based on occupancy."
In preparation for the retrofit, Phillips conducted a test to narrow down the product options and help ensure the effectiveness of the LEDs.
"We basically brought in different fixtures from different manufacturers and ran a test in the lower level of one of our parking facilities, and we took readings before and after. We took different occupancy sensors, and even different technologies — fluorescent, induction, LEDs," she says. "We did a preliminary study, and from there we hired an outside consultant to take the study further, then manage the project and construction."
Phase one of the project, which started in December 2012 and finished in April 2013, involved three parking structures. The largest is the Oak Street Ramp, with 2,181 spaces and 928 LED lighting fixtures. The Church Street garage has 237 spaces and 146 fixtures, and the Northrop Garage has 74 spaces and 50 fixtures.
"The plan is to go across campus and do all parking ramps, garages, and even open lots. We're just getting ready to start phase two, which will be five parking garages and 1,700 fixtures. Phase three will wrap up the project. That has four additional garages and about 125 parking lots." All work is scheduled to finish by June 2015.
Phase one cost the department $860,000 for fixtures, labor, and controls, and it has paid dividends already.
"We've seen some great results so far," Phillips says. "We've been able to save 30 percent, which is actually higher than anticipated. Within that 30 percent, about half of it was due to the controls. We haven't had any feedback, and with lighting, no feedback is good feedback."
Lighting Retrofits at University of Minnesota Deliver Energy Savings
Parking Structures Frequent Target of LED Opportunities
Stairwells, Hallways Other Sources of LED Installations
Benefits and Challenges Presented by LED Retrofits
A Closer Look Online Exclusive: The University of Minnesota's Lighting Retrofits
