Dual-Loop Photosensor Control System for Daylight Harvesting: West Sacramento Walmart
To maximize the respective benefits of open- and closed-loop systems, and minimize their limitations, the California Lighting Technology Center (CLTC) developed a dual-loop photosensor control system for skylight applications. The system features a control algorithm that monitors the open- and closed-loop photosensors and controls the electric light to provide the designed light level. It also automatically recalibrates nightly to adjust to long-term changes to the interior space. Results show the dual-loop technology delivers more consistent lighting and greater energy savings.