Cal State Sacramento LED Lighting Retrofit Project with Advanced Lighting Controls
The rapid decrease in the cost of LED lighting, as much as 85 percent over the past decade, is having a major impact on the adoption of this promising technology. Across California, campuses are specifying 100-percent LED lighting in many new buildings and piloting LED retrofits in existing buildings, in many cases leading to compelling energy savings. Evidence of this is seen in the two Best Practices Awards from this year, as well as projects recognized in previous years.
The lighting retrofit at Mendocino Hall demonstrates the energy saving opportunity in many older buildings having T-8 fluorescent fixtures and rudimentary lighting controls.
At Cal State Sacramento, an LED retrofit and advanced controls project has reduced lighting by close to 50 percent below Title-24 benchmarks. This work was done in Mendocino Hall, a five-story academic building that houses classrooms, offices and labs. Constructed in 1990, the building had been subsequently retrofit with T-8 fluorescent lamps, electronic ballasts and simple occupancy-based lighting control, and as such is representative of many campus buildings.
Exterior view of Mendocino Hall.
Before the retrofit, the building had occupancy sensors in most offices and classrooms, however that left many spaces such as corridors, stairs and restrooms with lights on 24/7. Although a full building retrofit was preferred, for budget reasons the project team focused the work on these spaces. An important goal of the control upgrade was to connect the building lighting to the existing campus-wide automatic demand response (ADR) system. The system, based on a Tridium building management system, allows building HVAC systems to respond to utility signals by increasing temperature set points and limiting fan speeds.
The project team conducted an analysis of four potential lighting control products, and selected the system from Enlighted for its extensive control for dimming, daylight harvesting, and ability to configure control by zone. The physical elements of the system consist of fixture controllers, wall switches, ceiling-mounted sensors, wireless gateways, and the “Energy Manager,” a local server that provides a web-based user interface to the control network. Many of the elements communicate via a wireless network, reducing wiring requirements, installation cost and potential disruptions from installation. A graphical interface provides highly granular metering and control down to the level of individual fixtures. The ceiling sensors measure occupancy, ambient light and temperature. With the installation of the new controls, lighting levels in Mendocino Hall can now be programmed to respond to ADR signals from its utility, the Sacramento Municipal Utility District (SMUD).
Sample lighting power screen from the Enlighted interface. The two boxes point to lighting reductions in response to signals from the automatic demand response system.
The team installed a total of 333 LED fixtures, including six-inch recessed cans, cove lights, semi-direct pendant lights, and three types of troffer fixtures. Some of the greatest energy savings came from the replacement of 92-watt 2x2 troffers with 18.7-watt LED fixtures, and replacing 300-watt recessed cans with 36.5-watt LED alternatives.
When the project was completed and publicized around campus, it was well received and several departments inquired about having installations in other buildings. Nathaniel Martin, the campus Energy Manager, notes several important considerations for such projects: “Select a general contractor with lighting controls experience, and make sure the project specifications are very clear and direct. In hindsight, some of our lighting control details probably should have been listed in the drawing notes. Another important point is to get the IT department involved early in the process to confirm technology compatibility regarding wireless systems.” As campuses adopt LED lighting and advanced controls, the learning curve for facilities staff may be smoothed by involving experienced consultants and contractors, which can contribute to improved in-house knowledge and experience over time.
Top image copyright Google. Small images copyright Sacramento State.