Study on Daylight and Electric Light Combination Modes in Classrooms from the Perspective of Rhythm Health:Assessment,Optimization Tools and Application

XU Junli; TONG Diehong

doi:10.3969/j.issn.1000-0232.2024.12.005

Abstract：With growing awareness of"healthy China",there is an increasing demand for healthy building design.For adolescents,insufficient lighting can disrupt the stability of circadian rhythms,posing long-term risks to their physical and mental health.Few studies have discussed the combination modes of daylight and electric light,and non-visual threshold requirements are often overlooked.A light environment that simply meets the visual effect threshold cannot satisfy people's more extensive health demands.It is necessary to use the quantitative indicator melanopic EDI of non-visual effect to explore classroom light environments. In this study,a simulation model of a typical classroom lighting environment in Suzhou was constructed through DIALux evo software.The variation laws of melanopic EDI across classroom seating areas and its compliance under daylight and a combination of daylight and electric lighting were analyzed.Results showed that the rhythmic stimulation level in the classroom under daylight was not a constant value from a temporal perspective.Spatially,the classrooms exhibited higher rhythmic stimulation levels in the northern areas and lower levels in the southern areas.Although turning on electric lighting can improve the rhythmic stimulation level in classrooms,there are still uneven rhythmic stimulation levels,which shall be further studied. This analysis led to the development of an optimization tool and process of the light environment using the spectral characteristics of light sources for a reasonable allocation of daylight and electric lighting in classrooms for"different periods"and"different regions",aiming to increase the design efficiency of the light environment in classrooms.Finally,the combined daylight and electric lighting mode was applied to a typical classroom in Suzhou during cloudy days in winter,verifying the tool process's feasibility and effectiveness.After the optimization,PUS,4h of the seating area in classrooms increased from 45.83％to over 75％,significantly enhancing the non-visual effects of the light environment in classrooms. This study optimizes the combination of daylight and electric lighting in classrooms through simulation assessments,optimization tools and applications;proposes the corresponding control strategies;and summarizes paths to improve adolescents'rhythmic health.Research results provide an idea of how to control rhythmic lighting in classroom space.This lays a theoretical reference for selecting daylight and electric lighting combinations in classroom space and facilitates the extensive applications of nonvisual light environmental design to classroom space.