Case study: Lighting control panel upgrade provides dramatic improvement for a university
Lander University in Greenwood, S.C., relied on a programmable relay-based system installed in the mid-1980s to provide energy-saving scheduled control of lighting and equipment for its most vital buildings. The system was in need of an upgrade.
Lander University in Greenwood, S.C., relied on a programmable relay-based system installed in the mid-1980s to provide energy-saving scheduled control of lighting and equipment for its most vital buildings.
While the system, which controlled the learning center, cultural center, student center, and athletic complex, served its purpose initially, the controls had become antiquated and unreliable. After experiencing numerous disruptions to classes and events, engineers at the state university set out to research replacement options. The school’s engineering services department personnel priced equipment and installation costs, and eventually found a solution.
For less than 10% of the cost of a new system, they could refurbish the existing panels to create a modern control system. The university could significantly extend the life of its capital equipment and avoid sending materials to a landfill. Additionally, the upgrade would take much less time than a full replacement.
After more than 20 years of service and numerous undocumented modifications, the original control system was only about 75% functional. Some relays had failed on; the lights were operational, but power was wasted. The time required to program the system for special events was prohibitive, and the process was risky, because the disk drive needed to load even a single change was unreliable and obsolete. And because of staff turnover, no one really understood the system.
Campus engineers need reliable controls that are easy to program. An early adopter of scheduled control, Lander University is among one of the most energy-efficient campuses in the state, as reported by the South Carolina Energy Office. In addition to lighting, the relays power water-source heat pumps and other electrical devices, so careful scheduling is truly central to conservation efforts.
The newly retrofitted system allows Internet protocol control of all the panels. Engineers can create and modify schedules for equipment and lighting in individual spaces including common areas, classrooms, labs, and offices. To maximize energy savings, engineers programmed most of the lighting for manual-on, using previously installed low-voltage switches, and scheduled-off. Certain overrides are available, but engineers now prefer to adjust the control schedule as needed.
“Normally equipment and lighting goes off around 5 p.m., but for special events or seminars, we can have just one specific area turn off at 9 p.m., for example,” said staff engineer Ralph Jenkins. “It used to be a nightmare to do this, but with the new scheduling software it’s easy. The system has lots of bells and whistles and is very user-friendly.”
Engineers finished the panel upgrade during spring break in 2007 so that there was no disruption to classes or other events. Lander engineering personnel performed the work themselves under the direction of a technician, and so they became more familiar with the system and will better be able to service it in the years ahead.
The upgrade process involved replacing the main control card in each panel with a new card and thoroughly testing and inspecting the panel. Any failed relays were replaced. Additionally, the bulky old controller was replaced with a small dataline power supply to power the low-voltage controls. Wiring was run for a data communications link and the WebLink, and scheduling is now performed in a convenient location on a PC.
Retrofitting the old relay system allowed Lander University to continue using the portion of the controls with the longest service life while replacing parts that were obsolete. Because the panels themselves did not have to be replaced, installation costs were minimal, and the project didn’t require the services of an outside contractor.
The controls have been brought back to 100% operation and the existing system has been fully documented. Strict control of energy use, which in 2004 was a scant 67.42 kBtu/sq. ft—well below the state average of 123.93 kBtu/sq. ft for campuses with housing—is now much easier and the staff expects to be able to achieve additional savings in the future using the many options afforded by the new controls.
For more about lighting controls from Watt Stopper/Legrand, click here .