Τhe effect of artificial lighting on both biophilic and human-centric design

Abstract

The indoor environmental quality is very significant as humans spend more than 90% in indoor space. Biophilic design of indoor spaces has become a popular approach in the design of indoor building spaces sector using green walls, especially in offices, leisure and hospitality facilities. So far there exist neither guidelines with the proper Spectral Power Distribution (SPD) except for agricultural applications or intensity levels of lighting nor the proper spectral indices to transform the photopic illuminance to a new type of photometric quantity for biophilic design. On the other hand, for human centric lighting the Equivalent Melatonin Illuminance is already introduced. The aim of paper is to define the appropriate lighting conditions, not only for humans, but also for interior plants. A new metric was introduced for the biophilic design named Equivalent Photosynthetic Illuminance. The new metric was examined for two human-centric lighting luminaires and compared with the corresponding human centric lighting metrics in order to create a lighting design guide for energy-sustainable, biophilic and human-centered lighting. The different SPDs highlighted the counterbalancing impact(s) of such luminaires, between biophilic and human-centered design. The differences concerning their impact on interior lighting design were identified with regards to energy consumption, meaning that the compliance of the lighting conditions to both humans and plants results to higher energy consumption. Depending on the SPD and luminous efficacy of artificial lighting, the additional power density for proper planning of biophilic design can vary from 23.5W/m2 to 52.4W/m2 in the areas in which are applied.