摘要
Fiber-optics daylighting system(FODS)demonstrates significant potential for enhancing natural light utilization efficiency while enabling a more continuous visible spectrum illumination to support circadian rhythm regulation.It offers a promising solution for both building energy efficiency and indoor light environment comfort improvement.However,conventional FODS face critical limitations,including low coupling efficiency at the collector-fiber interface and uneven illumination distribution,which impede its practical application.Recent advancements in optical technology present new opportunities for performance optimization of the FODS.Departing from traditional homogenization approaches reliant on optical homogenizers,this study introduces a freeform-caustics-based collector design with discretized energy distribution across the receiving plane.This innovative freeform fiber-optics daylighting system(FFODS)simultaneously addresses localized thermal accumulation and improves coupling efficiency.Furthermore,diffuse transmission materials and a freeform lens are integrated as a dual-functional diffuser to reshaping emitted light and precisely manipulate optical wave fronts,thereby achieving stable and uniform illumination in the targeted area.On this basis,a systematically simulation analysis on the thermal characteristics and photometric performance of the system was conducted.The results validate that the FFODS achieves a 98.5%coupling efficiency with a 126 times reduction in geometric concentration ratio compared to Fresnel lens collector.The diffuser maintains illumination uniformity above 0.8 under bending and adjustment conditions,while realizing 91.5%workspace illumination efficiency in the targeted area.Overall,this novel FFODS provides a transformative technique for advancing conventional FODS with high efficiency and illumination uniformity.
基金
supported by the National Natural Science Foundation of China(Grant No.52478100,No.52425801,No.52130803,No.52408102)
the Natural Science Foundation of Sichuan Province(2024NSFSC0916)
the Natural Science Foundation of Jiangsu Province(BK20241348).
