Methodology for the optimization of artificial lighting considering both visual and non-visual effects

¹ Lighting Laboratory, School of Electrical & Computer Engineering, National Technical University of Athens, Iroon Polytechneiou 9, Zografou Campus, 15780, Athens, Greece
² School of Applied Arts and Sustainable Design, Hellenic Open University, Parodos Aristotelous 18, Patras, 26335, Greece
³ Department of Architecture, University of Thessaly, Greece

^* Corresponding author: madias@mail.ntua.gr

Abstract

The effect of light on human physiology as well as its non-image forming effects have been known for several years. An important milestone in understanding the non-visual effects of light was the discovery of a new type of photoreceptor namely the intrinsically photosensitive retinal ganglion cells, or ipRGCs which play a vital role in the human circadian system. The non-visual effects of light are the following: regulation of melatonin secretion, circadian entrainment and modification of body temperature. With the advent of solid-state lighting, it is possible to precisely regulate the spectral power distribution of artificial lighting, so as to favour the human circadian rhythm. The scope of this paper is to present a conceptual methodology for the evaluation of artificial lighting systems with regards to visual, circadian effects and their energy consumption. In other words, this paper aims to outline an assessment process for lighting designers by elaborating not only on the visual aspects of each lighting system but also the melanopic effects and its energy efficiency.