CIE x050-PO005 PDF

This paper introduces an efficient daylighting technology designed to enhance lighting conditions in deep interior spaces of multi-story buildings without increased solar heat gains. This passive horizontal solar light pipe redirects sunlight effectively to distances ranging from 5 m to 10 m from the facade. Photometric measurements conducted over the course of a year demonstrate that the system consistently delivers illuminance levels exceeding 300 lux for 9 hours (9:00-18:00) under clear and partly cloudy skies, and for 4 hours under overcast sky conditions (when the exterior global horizontal illuminance exceeds 18-20 klux). Under clear sky conditions, illuminance values surpassing 1,000 lux are achieved between 10:30 and 16:30. The light pipe ensures consistent illuminance levels ranging from 300 lux to 3,000 lux throughout the year, resulting in energy savings during peak electricity demand periods. It provides the necessary daily doses of bright light to entrain circadian rhythms of occupants.