Page 128 - Zero Net Energy Case Study Buildings-Volume 1

CASE STUDY NO. 6
CLASSROOM & OFFICE BUILDING
112
Zero Net Energy Case Study Buildings: Volume 1
Post-Occupancy Adjustments to Lower Energy Use: Lighting Systems
Adjustment of the Lighting Control System Operation
The experience with the Classroom & Office Building followed that of the Science & Engineer- ing Building I. Namely, the post-commissioning issues with lighting were the same: during early occupancy of this building, there was also a lack of connection between the campus BMS and the building’s lighting control systems. As in the case of the HVAC system, it was discovered that schedule changes programmed into the campus BMS did not affect the building lighting controls. With the correction to this problem, UC Merced staff were able to tune the building operation to the room schedules and reduce the energy use through setbacks and light level reductions.
These setbacks were established in the Classroom & Office Building for the auditoriums, con- ference rooms and classrooms. The lighting in private office spaces is controlled by local mo- tion and infrared occupancy sensors. Each lighting zone is part of a “scheduling area”, which includes the HVAC equipment components related to the same space or room. In this way, the lighting and HVAC are linked by the control system and operate together to serve the space.
The lighting control logic for the common area spaces is as follows:
1. Lighting is strictly scheduled on and off. This is a basic approach in public spaces such as hallways and lobbies. Local manual switches are overridden to be inactive during the scheduled occupied period.
2. Lighting is scheduled occupied, but not turned on. The lights only turn on if someone enters the zone and uses a manual light switch. The lights then remain on until the end of the scheduled period, when all lights turn off. This is a typical operation in classrooms and conference rooms, where users have complete control of the lights. Manual light switches can also override the unoccupied schedule for one-hour increments; the link to the HVAC system signals a ramp-up of space conditioning for the override period.
3. Lighting is scheduled to turn on at sunset and off when the schedule expires. This type of schedule is used in zones at the building perimeter with a large amount of daylight. Manual light switches can override the schedule for one-hour increments.
Exterior lighting is set to operate on a sunset-to-sunrise schedule. The time at which each of these events occurs is updated daily.