کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
262610 | 504043 | 2015 | 13 صفحه PDF | دانلود رایگان |
• Reducing energy consumption caused by artificial lighting and air-conditioning.
• Providing uniform redirected sunlight with stable sunlight area.
• Redirecting 70% sunlight toward ceiling 7 m far at 40–70° solar elevation angles.
• Reducing 82% transmittance and increasing 6 times reflectance in IR region.
Air-conditioning and artificial lighting consume over 50% of the energy in a building. Decreasing thermal loading and introducing sunlight into a building can effectively save electricity and reduce greenhouse effect. This study reports a design for a passive prismatic sunlight-redirecting microstructure coupled with infrared (IR) insulation. The infrared insulation is an anti-reflection nanostructure with a silver thin film. The base design uses a quadrangular prism with a 45° vertex angle and a height and pitch of 50 μm to direct the high intensity sunlight deep into the room; unfortunately, this design produces harmful glare, and the area lighted by the redirected sunlight drifts as the varies sunlight during the day. The prism is further modified using an inclined-curved complex, which has 18.3 μm pitch and 20.91 μm height. The curved plane can diffuse the sunlight into a wide-angle exiting sunlight beam, which provides uniform sunlight with a stable daylighting area. The experimental results show that the daylighting redirection efficiency reaches 70% at solar elevation angles of 40–70° and that the daylighting area can reach up to 7 m deep into the room. The average transmittance is lower than 15.46%, and the reflectance is higher than 75.64% at infrared wavelengths.
Journal: Energy and Buildings - Volume 90, 1 March 2015, Pages 114–126