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Harvesting light reaps energy savings for ASU's Hayden Library

August 22, 2012

Before ASU Facilities Development and Management began adding light controls to Hayden Library, the manual switches which previously controlled all seven floors and lights were left on 24 hours a day, seven days a week, except for weekend hours. 

Now, thanks to the Sustainability Initiative Revolving Fund (SIRF) project, which began in May, ASU's Hayden Library is looking at major energy savings.

"With the advent of lighting controls we now have the ability to have the lights turn off in any unoccupied area," said Robert W. Vandling, technology support analyst coordinator and Hayden project manager. "Many areas in the library are unoccupied during the evening and early morning hours, particularly the stacks. The lights switch on automatically when someone enters the controlled space."

Based upon a controlled test performed last year on the second floor, it is expected that the electrical consumption for lighting will be reduced by 43 percent. At the current electrical rate, this equates to an annual cost savings of approximately $45,500, and a pay back of less than four years from project completion.

Using wireless technology for the occupancy sensors has greatly simplified installation since no electrical wiring is necessary. These sensors are powered through light-harvesting technology that reduces maintenance and operational costs. The sensors communicate with relays that are wired into the zoned lighting circuits and a gateway device is installed that allows the lighting control system to communicate with ASU’s building management system. As changes to the space occur over time due to use, remodels and occupancy, this technology remains readily adaptable.

The lighting-controls project is one of many that are moving ASU closer towards its goal of carbon neutrality by 2025.

To learn more about SIRF and how to submit a SIRF proposal, visit: or email: