Architecture / Mimarlık

Permanent URI for this collectionhttps://hdl.handle.net/11147/24

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Author: search.filters.author.Wittkopf, StephenPublication Index: search.filters.publicationIndex.Scopus

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  • Article
    Citation - Scopus: 3
    Climate Based Daylight Simulations With Evaldrc - Analysis of Daylight Redirecting Components
    (TU Delft Open, 2017) Bauer, Carsten; Kazanasmaz, Zehra Tuğçe; Wittkopf, Stephen
    The new calculation tool EvalDRC enhances current strategies for the simulation of Daylight Redirecting Components (DRCs). It is built upon RADIANCE as a core simulation engine and uses the daylight coefficient method, climate based sky models for annual simulations, and daylight metrics for data reduction. Contribution Photon Mapping is introduced as a new method for physically correct DRC simulation. Further new features are: separate True Sun Coefficients for a less approximated, more accurate treatment of the sun contribution and monthly breakdowns of the Spatial Daylight Autonomy, and Annual Sunlight Exposure metrics for more detailed information about DRC performance over the course of the year. To show the versatility of the tool, two application studies were carried out in which either measured Bidirectional Scattering Distribution Functions (BSDF) or detailed geometry models were used for the DRC simulation. © This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. Author(s) hold their copyright without restrictions.
  • Article
    Citation - Scopus: 8
    High-Resolution Data-Driven Models of Daylight Redirection Components
    (TU Delft Open, 2017) Grobe, Lars Oliver; Wittkopf, Stephen; Kazanasmaz, Zehra Tuğçe
    Daylight Redirecting Components (DRCs) guide daylight to zones with insufficient daylight exposure. They reduce energy demand for lighting, heating and cooling, and improve visual and thermal comfort. The data-driven model in Radiance is a means to model DRCs in daylight simulation. Rather than internal optical mechanisms, their resulting Bidirectional Scattering Distribution Function (BSDF) is replicated. We present models of two DRCs that are generated from measurements. The impact of the following three necessary steps in the generation of data-driven models from measured BSDF shall be evaluated: 1) interpolation between measurements at sparse sets of incident directions; 2) extrapolation for directions that cannot be measured; 3) application of a directional basis of given directional resolution. It is shown that data-driven models can provide a realistic representation of both DRCs. The sensitivity to effects from interpolation differs for the two DRCs due to the varying complexity of their BSDFs. Due to the irregularity of the measured BSDFs, extrapolation is not reliable and fails for both tested DRCs. Different measurement and modeling protocols should be applied to different class systems, rather than aiming at a common low-resolution discretization.
  • Article
    Citation - WoS: 40
    Citation - Scopus: 51
    Three Approaches To Optimize Optical Properties and Size of a South-Facing Window for Spatial Daylight Autonomy
    (Elsevier Ltd., 2016) Kazanasmaz, Zehra Tuğçe; Grobe, Lars Oliver; Bauer, Carsten; Krehel, Marek; Wittkopf, Stephen
    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 films' 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 films' potential to improve the performance of windows with reduced WWR.