Enhancing Natural Daylight Capture by Optimizing the Geometry of Tubular Light Guides Equipped with Optical Lenses

Effective use of natural lighting significantly contributes to indoor environmental quality, energy savings, health, and comfort. Tubular Light Guides (TLGs) represent one technique for maximizing the exploitation of natural daylight. Their purpose is to capture sunlight and bring it into a room. However, conventional TLGs have limited light-capturing efficiency under overcast conditions and at low to moderate solar elevation angles, resulting in insufficient indoor illuminance distribution. The objective of this paper is to improve the efficiency of natural light capture by optimizing the geometry of TLGs integrated with an optical lens, representing a new TLG design. A comparative experimental investigation was conducted using two identical small-scale rooms equipped with different TLG configurations. The light distribution performance of the TLGs was compared under both cloudy and sunny conditions through these performance tests. The experimental results show that the modified TLG design achieved higher indoor illuminance performance than the conventional configuration. It was observed that the enhanced TLG improved the performance of capturing and redirecting light into the living space by an average of ۴۰% under an overcast sky and ۶۰% under sunny conditions. In addition, biconvex and biconcave lenses enabled better light penetration under different weather conditions and at different times, providing better visual comfort and energy savings. Finally, the fabricated TLG can improve the utilization efficiency of natural daylight in buildings, offering an eco-friendly indoor illumination scheme and helping to reduce carbon emissions.

کلیدواژه ها:

Daylight ، Energy Saving ، Lenses ، Natural Lighting ، TLGs