@article{97,
  keywords = {BSDF, daylight, radiance, redirection, sDA, window design},
  author = {Tuğçe Kazanasmaz and Lars Grobe and Carsten Bauer and Marek Krehel and Stephen Wittkopf},
  title = {Three approaches to optimize optical properties and size of a South-facing window for spatial Daylight Autonomy},
  abstract = {This study presents optimization approaches by a recent Climate-Based-Daylight-Modeling tool, EvalDRC, to figure out the necessary area for a daylight redirecting micro-prism film (MPF) while minimizing the glazing area. The performance of a window in terms of spatial Daylight Autonomy (sDA) is optimized by its geometry and optical properties. Data implemented in simulation model are gathered through on-site measurements and Bidirectional-Scattering Distribution Function (BSDF) gonio-measurements. EvalDRC based on Radiance with a data driven model of the film's BSDF evaluates the window configurations in the whole year. The case to achieve an sDA of at least 75% is a South-facing window of a classroom in Switzerland. A window zone from 0.90 m to 1.80 m height provides view to the outside. The upper zone from 1.80 m to 3.60 m is divided into six areas of 0.30 m height in three optimization approaches including the operation of sunshades as well. First, the size of the clear glazing is incrementally reduced to find the smallest acceptable window-to-wall ratio (WWR). Second, micro-prism films are applied to an incrementally varying fraction the initial glazed area to determine the minimum film-to-window ratio (FWR). Finally, both approaches are combined for a minimum FWR and WWR. With clear glazing and WWR of 75%, the sDA of 70.2% fails to meet the requirements. An sDA of 86.4% and 80.8% can be achieved with WWR 75%, FWR 1/9 and WWR 50%, FWR 1/2 respectively. The results demonstrate the film's potential to improve the performance of windows with reduced WWR.},
  year = {2016},
  journal = {Building and Environment},
  volume = {102},
  chapter = {243},
  pages = {243-256},
  month = {June},
  issn = {0360-1323},
  url = {http://www.sciencedirect.com/science/article/pii/S0360132316300956},
  doi = {10.1016/j.buildenv.2016.03.018},
  language = {eng},
}