Integrated Performance of an Automated Venetian Blind/Electric Lighting System in a Full-Scale Private Office
Comprehensive results are presented from a full-scale testbed of a prototype automated venetian blind/lighting system installed in two unoccupied, private offices in Oakland, California. The dynamic system balanced daylight against solar heat gains in real-time, to reduce perimeter zone energy use and to increase comfort. This limited proof-of-concept test was designed to work out practical "bugs" and refine design details to increase cost effectiveness and acceptability of this innovative technology for real-world applications. We present results from 14 months of tuning the system design and monitoring energy performance and control system operations. For this southeast-facing office, we found that 1-22% lighting energy savings, 13-28% cooling load reductions, and 13-28% peak cooling load reductions can be achieved by the dynamic system under clear sky and overcast conditions year round, compared to a static, partly closed blind with the same optimized daylighting control system. These energy savings increase if compared to conventional daylighting controls with manually-operated blinds. Monitored data indicated that the control system met design objectives under all weather conditions to within 10% for at least 90% of the year. A pilot human factors study indicated that some of our default control settings should be adjusted to increase user satisfaction. With these adjustments, energy savings will decrease. The final prototype design yielded a 10-year simple payback for this site. If mechanical system downsizing opportunities and qualitative improvements to worker's comfort are included, this innovative technology could be more cost effective. Marketing information for commercializing this technology is given.