Architecture / Mimarlık

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

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Institution Author: search.filters.institutionAuthor.Grobe, Lars OliverSubject: search.filters.subject.Bidirectional Scatter Distribution Function

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Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 12
    Citation - Scopus: 15
    Characterization and Data-Driven Modeling of a Retro-Reflective Coating in Radiance
    (Elsevier Ltd., 2018) Grobe, Lars Oliver
    Retro-reflective coatings applied to blinds of reduced geometric complexity promise to provide view to the outside while effectively controlling solar gains and glare. To characterize the reflection characteristics of such coatings over the entire solar spectrum, a novel extension to a scanning gonio-photometer is developed. The extended instrument is tested and applied to measure a coating's Bidirectional Reflection Distribution Function including the region of the retro-reflected peak. The measured datasets are compiled into a data-driven reflection model for the daylight simulation software RADIANCE. This model is applied to illustrate the coating's effect in a comparison to purely diffuse and specular surface finishes on geometrically identical, flat blinds. Daylight supply, the probability of glare, and solar gains are assessed for an exemplary, South-oriented office under sunny sky conditions. The results indicate the potential of the coating to effectively shade direct sunlight even if applied on blinds with minimalistic geometries. The modeling technique is shown to be a general means to replicate the irregular optical properties of the coating, which cannot be represented by the standard models in daylight simulation software.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 8
    Computational Combination of the Optical Properties of Fenestration Layers at High Directional Resolution
    (MDPI Multidisciplinary Digital Publishing Institute, 2017) Grobe, Lars Oliver
    Complex fenestration systems typically comprise co-planar, clear and scattering layers. As there are many ways to combine layers in fenestration systems, a common approach in building simulation is to store optical properties separate for each layer. System properties are then computed employing a fast matrix formalism, often based on a directional basis devised by JHKlems comprising 145 incident and 145 outgoing directions. While this low directional resolution is found sufficient to predict illuminance and solar gains, it is too coarse to replicate the effects of directionality in the generation of imagery. For increased accuracy, a modification of the matrix formalism is proposed. The tensor-tree format of RADIANCE, employing an algorithm subdividing the hemisphere at variable resolutions, replaces the directional basis. The utilization of the tensor-tree with interfaces to simulation software allows sharing and re-use of data. The light scattering properties of two exemplary fenestration systems as computed employing the matrix formalism at variable resolution show good accordance with the results of ray-tracing. Computation times are reduced to 0.4% to 2.5% compared to ray-tracing through co-planar layers. Imagery computed employing the method illustrates the effect of directional resolution. The method is supposed to foster research in the field of daylighting, as well as applications in planning and design.
  • 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.