"The space stays bright and comfortable throughout the day and evening with no effort and is reducing library operating costs," said Julie Farnsworth, director of Pleasanton Library Services.
Pleasanton made it a priority to replace or upgrade the lighting in all of its public buildings as part of its Climate Action Plan, and the 30,300-square-foot library, built in 1987, was chosen for the first upgrade because it used the most energy.
The installation was done by Adura Technologies, a company out of San Francisco that specializes in wireless lighting controls and energy management systems.
"The Adura Wireless Lighting Control System offers a great solution to the unusual challenges presented by libraries," said Mark Golan, Adura CEO. "Adura's proven technology is nimble enough to meet the lighting needs of a public facility with multiple uses."
Libraries have difficultly using lighting controls, such as occupancy sensors, because the sensors typically have to be hard wired to the fixtures they control and tall shelving often interferes with their effectiveness.
The Pleasanton library's controls previously were limited to three main switches that controlled most of the building's lighting, and there were no timers or automation. Despite several skylights, large windows and different use of the library at different times by staff and patrons, the library's 661 lights were on from when the first staff arrived in the morning until the last person left at night -- approximately 13 hours a day, seven days a week.
Adura's lighting control system uses photocells to make the most use of daylight by detecting when it dims as well as detecting occupancy for a gradual transition from full light to no light. Smart scheduling allows for whether the library is fully occupied or only the staff is there, and with task tuning, the new lamps are set at 80 percent of maximum, which can be adjusted as fixtures age.
With the new system, the high bookshelves in the library are no longer a lighting issue because the wireless mesh network allows lights to receive input from multiple sensors and also for sensors to control multiple lights.
Adura also trained the library staff to use the new system and software that controls it.
"Watching our lighting energy use fluctuate from between 30% and 70% throughout the day, compared to our previous usage, shows that it is really working," said Chris Rizzoli, Pleasanton Supervisor of Support Services.
Rizzoli noted that energy use and individual fixture light output are displayed on the Adura Enterprise Application, which can be accessed from the Internet.
"The on-screen data allows us to track our daily usage and know exactly where problems occur in real-time," he said.
The project took about one month to complete, at a cost of $166,000, which will be recouped in just over six years. The library's electricity cost the city approximately $46,000 each year before the upgrades; the new system savings is estimated at $21,100 annually.
The city received a PG&E rebate of $4,800 and a rebate of $25,500 from the Energy Technology Assistance Program (ETAP), which is part of the Energy Upgrade California program.
"We are happy with the project, and the patrons enjoy excellent lighting at a lower cost," said Library Director Farnsworth.
The library serves just under 1 million visitors each year.