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Daylight Harvesting: Overhaul for Outmoded Technology
May 26, 2011
By Joyce Hui
Conservation and expansion are intertwined concepts that are fundamental to the Physical Plant & Capital Planning Services at the University of Western Ontario. Physical Plant staff is constantly brainstorming and researching methods to conserve energy by expanding on sustainable initiatives across campus.
Notably, HVAC/IAQ technologist, Steve Mackay, has piloted a daylight harvesting initiative that allows dimming controls and light circuit metering in the nine-storey Social Sciences Building (SSC), home to Western’s largest faculty and one of the largest Social Science faculties in Canada. This provides an effective means of capitalizing on natural resources while reducing energy costs and consumption.
“We save money, we save the environment, and we live and model what we teach to students – our future world leaders,” says Gitta Kulczycki, Vice-President, Resources & Operations at Western. “Not too many things can do all that.”
The lighting control initiative was inspired by an earlier energy reduction project that implemented controls for the baseboard heaters in the SSC building’s office spaces. It focused on nine circuits on the fourth floor, and demonstrated successful results of 29.6% in energy savings over a 24-hour operating time period and 46% during peak time periods, exceeding the original goal of 15 to 20% energy savings during a full day and 30% during peak hours. Subsequently, the completion of floors one to nine involved control of 80 circuits, or approximately 450 individual baseboard units.
To apply this concept to the building’s lighting system, T12 fluorescent lights with magnetic ballasts were retrofitted with T8 lamps with electronic ballasts. Since the building houses more than 6,000 undergraduates and 400 graduate students, the lighting alterations were carried out in the evening when occupancy was sparse. The majority of the work on the controls was performed through electrical closets on each floor so that lectures in classrooms and meetings in offices were not interrupted in any way.
Simply retrofitting of the T8 lamps delivers a nominal saving of 30%. However, in combination with dimming controls, the T8 lamps operate at only 40% of full power during the daytime when natural light serves as the dominant source of light energy. That results in a 60% energy saving during daytime levels and 80% savings during off-peak hours.
Based on review of available technologies, the lighting control methodology has also expanded to the elevator lobbies of every floor through the use of power line carriers. The control technology continues to be upgraded to further expand the results and to maximize the potential of the sustainable initiative.
The combined baseboard heating and lighting control technology will result in a 2.8-year simple payback. The expansion of the system to the remaining areas in the complex and implementation of wider control strategies will lower this value over the coming months.
Additionally, energy management software will soon allow anyone to see and monitor meter readings on-line – a scenario that Mackay looks forward to as educational tool and potential stimulus for conservation. “Once people see how much energy we’re using every day, and everybody’s going to know in their building how much energy is used, I think they’re going to be astonished,” he predicts.
That’s in keeping with Western’s commitment to creating a sustainable environment, plus using space thoughtfully and responsibly to preserve the beauty and integrity of its campus.
Joyce Hui is a student in the faculty of Media, Information and Technoculture at University of Western Ontario, who has just completed a communications internship with Western’s Physical Plant & Capital Planning Services. For more information see the web site at www.uwo.ca.
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