01627nas a2200157 4500008004100000245007200041210006900113260001800182300001100200490000700211520110000218100002501318700002101343700002701364856007801391 1997 eng d00aAdvanced Optical Daylighting Systems: Light Shelves and Light Pipes0 aAdvanced Optical Daylighting Systems Light Shelves and Light Pip aCleveland, OH a91-1060 v263 a
We present two perimeter daylighting systems that passively redirect beam sunlight further from the window wall using special optical films, an optimized geometry, and a small glazing aperture. The objectives of these systems are (1) to increase daylight illuminance levels at 4.6-9.1 m (15-30 ft) from the window aperture with minimum solar heat gains and (2) to improve the uniformity of the daylighting luminance gradient across the room under variable solar conditions throughout the year. The designs were developed through a series of computer-assisted ray-tracing studies, laser visualization techniques, and photometric measurements and observations using physical scale models. Bi-directional illuminance measurements in combination with analytical routines were then used to simulate daylight performance for any solar position, and were incorporated into the DOE-2.1E building energy analysis computer program to evaluate energy savings. Results show increased daylight levels and an improved luminance gradient throughout the year compared to conventional daylighting systems.
1 aBeltran, Liliana, O.1 aLee, Eleanor, S.1 aSelkowitz, Stephen, E. uhttps://facades.lbl.gov/publications/advanced-optical-daylighting-systems