Feasibility study on a novel daylighting system with embedded micro compound parabolic concentrators (CPCs)

A novel glazing system consisting of a polymer layer with embedded micro compound parabolic concentrators (CPCs), which is attached to a glass pane of glazing, is proposed. It aims to reduce the energy consumption due to cooling in buildings, provide daylighting, and maintain the transparent view. In the present work, the daylighting system is modelled for ray-tracing simulation, and the angular-dependent transmittance at the azimuth angle of 0 degrees is calculated. Structural characterization is conducted using optical microscope for the microstructures which serve as support for the reflective thin films of a micro CPC. Based on self-shading effect of a microstructure, facet-selective deposition of Aluminum with various thickness has been achieved by physical vapor deposition. Spectral measurement has been used to characterize the optical properties of the Aluminum thin films. Diffraction effect with respect to the thin film thickness on the transmission of linear micro-CPCs arrays is investigated by a monochromatic laser beam and visual observation. The results of the present work provides the reference for the optimization of the transmittance of the deposited thin film for a micro CPC, in order to achieve the desired optical property.