Annual Performance Metrics for Photosensor controlled Daylight-Responsive Lighting Control systems

摘要

Modern daylighting software programs are capable of performing sophisticated simulations of photosensor controlled lighting systems. The analysis of these simulations can be used to make more informed design decisions. This paper presents a multi-stage analytical approach for evaluating factors such as photosensor mounting location, control algorithm, and calibration strategies. The authors suggest amendments to the correlation coefficient method employed in prior studies by proposing the application of a critical point. Two additional metrics, based on Root Mean Square Error (RMSE) and Annual Energy Savings, are introduced. Collectively, these measures can be used to evaluate spaces with complex geometries, selected photosensor equipment and control-algorithms, and non-standard lighting systems. For the sample classroom space analyzed in this research, an RMSE analysis was found be a better predictor of the annual system performance than a correlation coefficient-based analysis. A RMSE analysis was also observed to be a much better predictor of the control system's relative energy savings. A calibration condition that limits the number of overdimming hours to 2% is suggested for use with the RMSE metric.