Daylighting design for healthy environments: Analysis of educational spaces for optimal circadian stimulus

The human biological clock, also known as circadian rhythm, is mainly synchronized by the light perceived, specifically short-wavelength. Insufficient access to daylight or equivalent electric lighting can compromise human health and well-being. The effect of light on the circadian rhythm is greater in children and adolescents than in adults, making lighting design for classrooms important for good circadian entrainment for students. This research shows the results of circadian stimulus autonomy, that is to say, the percentage of days during the year when circadian stimulus is above a minimum threshold in typical classroom designs. Circadian stimulus, promoted by either natural or electric lighting, is quantified. The venue studied has a window of variable size, position and orientation, as well as different reflectance values of the inner surfaces for a classroom under three typical sky conditions. As deduced from the results, the reflectance of the environment has a noticeable effect on circadian entrainment, as well as on the spectral distribution of the light source. The results also serve to compare the impact of architectural design parameters on promoting good circadian rhythm for students.