Evaluating Energy Efficiency and Colorimetric Quality of Electric Light Sources Using Alternative Spectral Sensitivity Functions

Abstract

Photometric and colorimetric quantities are calculated using spectral luminous efficiency and color matching functions (CMFs), respectively. Past studies highlighted the limitations of the standard sensitivity functions based on visual experiments conducted over a century ago. There have been new alternatives proposed, but the effect of the proposed alternatives functions on energy efficiency, and the colorimetric quality of light sources has rarely been investigated. It is reasonable to assume that updating photometric and colorimetric calculation procedures will make significant impacts on the characterization of electric light sources. Here, the impact of six luminous efficiency functions and six CMFs on luminous efficacy of radiation and chromaticity calculations were analyzed. Results indicate a significant effect of alternative functions on luminous efficacy of radiation (LER), chromaticity coordinates (CIE 1931 x,y and CIE 1976 u′,v′) and Duv. The biggest impact was caused by the change in the visual field of view (2-degree vs. 10-degree observer), highlighting the importance of visual field size for color and luminosity function. Updating the standardized luminous efficiency function may impact the performance characterization of electric light sources, but cost-benefit analysis should be studied to understand the broad impacts.

Keywords

• lighting quality
• energy efficiency
• luminous efficacy
• indoor environment
• sustainability
• light sources