Optimized lighting energy consumption for non-visual effects: A case study in office spaces based on field test and simulation

Abstract

Recently, the non-visual effects of the light environment have received increasing attention. Some standards have proposed evaluation metrics for non-visual effects in office spaces to ensure the health and well-being of occupants. Non-visual metrics are new requirements for indoor light environments, whose impacts on lighting adjustment and ultimate lighting energy performance are currently unknown. Therefore, this study aimed to present a workflow to obtain optimal light outputs considering non-visual lighting requirements, in addition to traditional visual requirements. This workflow was implemented to calculate the annual lighting energy consumption under different light correlated color temperatures (CCTs), daylight conditions, and standard requirements for an actual office scenario. As deduced from the results, adding non-visual requirements may significantly increase the lighting energy consumption by 57 %. Furthermore, daylight and light with a higher CCT are beneficial for non-visual energy-saving. The additional non-visual requirements will not increase the lighting energy consumption under favorable daylight conditions. The 5500 K light can save up to 20 % of the annual lighting power consumption than the 4000 K light. The presented workflow and conclusions contribute to engineering office environments with enhanced lighting, better circadian stimulus, and improved office lighting energy efficiency.