Evaluating Emerging Spectral Lighting Software: Comparing Measurements of Light Spectrum and Derived Metrics in a One-Room Laboratory Environment with Simulation Results

Abstract

ABSTRACT The goal of this study was to evaluate the use of new spectral simulation tool, Adaptive Lighting for Alertness (ALFA), by comparing software-predicted values of spectral irradiance, illuminance, and equivalent melanopic lux (EML) to corresponding measurements captured in a laboratory environment with light-emitting diode (LED) luminaires. Four lighting conditions were considered by varying the correlated color temperature (CCT) of the LED luminaires. Meter measurements of space geometry, spectral reflectance distribution (SRDs) of materials, and spectral power distribution of luminaires were used as input to the simulation. Simulated spectral irradiance values between 400 and 700 nm were generally within 10% of measured values, with many spectral bands having less than 5% error. Larger mean absolute percent error (MAPE) was observed for the mixed lighting conditions for bands between 420 and 490 nm, which subsequently influenced calculated EML values. Compared to horizontal measurements, vertical measurements were particularly susceptible to additional error through the measurement procedure and measurement equipment.