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Senior Scientist or Principal Investigator
01 May 2012 - 30 August 2021
Research or Laboratory Scientist
01 December 2008 - 01 May 2010
My primary research interest is daylight, being one way to make controlled use of solar energy in buildings. I am employing computational simulation, in particular the ray-tracing and photon mapping algorithms implemented in Radiance, as well as optical measurements to develop and test models. My research focuses on the evalutation of market-available products and the development of novel daylighting techniques, but also includes the study and reconstruction of daylight in historical sciences.
The irregular reflection and transmission properties of innovative fenestration allow the redirection, selectively admittance, or blocking of solar irradiation based on its incident direction. Compared to systems that implement adaptivity by mechanical transformations, such tailored light scattering reduces the complexity of installation, operation, and maintenance as well as the impact on outward view and the aesthetical appearance of buildings. Examples of such fenestration techniques (e.g., light redirecting films and Venetian blinds featuring irregular reflection properties) are presented with their gonio-photometrically measured scattering properties. Techniques to model optically complex fenestration to support product development and planning are presented. Effects on daylight availability, glare, and solar gains are demonstrated. Preliminary results indicate the potential to control and modulate rather than to block irradiation through the design of buildings aiming at high comfort and energy efficiency.
Lars Oliver Grobe. Irregular Light Scattering Properties of Fenestration for Comfortable and Energy-Efficient Buildings. International Journal of Digital Innovation in the Built Environment 2021, 10, 1 -16.
AMA StyleLars Oliver Grobe. Irregular Light Scattering Properties of Fenestration for Comfortable and Energy-Efficient Buildings. International Journal of Digital Innovation in the Built Environment. 2021; 10 (2):1-16.
Chicago/Turabian StyleLars Oliver Grobe. 2021. "Irregular Light Scattering Properties of Fenestration for Comfortable and Energy-Efficient Buildings." International Journal of Digital Innovation in the Built Environment 10, no. 2: 1-16.
A Bidirectional Scattering Distribution Function (BSDF) describes how light from each incident direction is scattered (reflected and transmitted) by a simple or composite surface, such as a window shade. Compact, tabular BSDFs may be derived via interpolation, discretization and/or compression from goniophotometer measurements. These data-driven BSDFs can represent any measurable distribution to the limits of their tabulated resolution, making them more general than parametric or analytical BSDFs, which are restricted to a particular class of materials. However, tabulated BSDFs present a trade-off between higher sampling loads versus lower directional accuracy during simulation. Low-resolution BSDFs (e.g., Klems basis) may be adequate for calculating solar heat gains but fall short when applied to daylight glare predictions. The tensor-tree representation moderates this trade-off using a variable-resolution basis, providing detail where needed at an acceptable cost. Independently, a peak extraction algorithm isolates direct transmission from any tabular BSDF, enabling high-resolution beam radiation and glare analysis through transmitting systems with a “vision” component. Our data-driven BSDF methods were validated with a pilot study of a fabric shade installed in an outdoor, full-scale office testbed. Comparisons between measurement and simulation were made for vertical illuminance, specular and near-specular transmission, and daylight glare probability. Models based on high resolution BSDF measurements yielded superior results when accounting for anisotropy compared to isotropic models. Models with higher resolution produced more accurate source luminance data than low-resolution models. Further validation work is needed to better characterize generality of observed trends from this pilot study.
Gregory J. Ward; Taoning Wang; David Geisler-Moroder; Eleanor S. Lee; Lars O. Grobe; Jan Wienold; Jacob C. Jonsson. Modeling specular transmission of complex fenestration systems with data-driven BSDFs. Building and Environment 2021, 196, 107774 .
AMA StyleGregory J. Ward, Taoning Wang, David Geisler-Moroder, Eleanor S. Lee, Lars O. Grobe, Jan Wienold, Jacob C. Jonsson. Modeling specular transmission of complex fenestration systems with data-driven BSDFs. Building and Environment. 2021; 196 ():107774.
Chicago/Turabian StyleGregory J. Ward; Taoning Wang; David Geisler-Moroder; Eleanor S. Lee; Lars O. Grobe; Jan Wienold; Jacob C. Jonsson. 2021. "Modeling specular transmission of complex fenestration systems with data-driven BSDFs." Building and Environment 196, no. : 107774.
This white paper summarizes the current state of the art in the field of measurement and simulation characterization of daylighting systems by bidirectional scattering distribution functions (BSDFs) and provides recommendations broken down by classes of systems and use cases.
David Geisler-Moroder; Eleanor S. Lee; Gregory Ward; Bruno Bueno; Lars O. Grobe; Taoning Wang; Bertrand Deroisy; Helen Rose Wilson. BSDF Generation Procedures for Daylighting Systems. BSDF Generation Procedures for Daylighting Systems 2021, 1 .
AMA StyleDavid Geisler-Moroder, Eleanor S. Lee, Gregory Ward, Bruno Bueno, Lars O. Grobe, Taoning Wang, Bertrand Deroisy, Helen Rose Wilson. BSDF Generation Procedures for Daylighting Systems. BSDF Generation Procedures for Daylighting Systems. 2021; ():1.
Chicago/Turabian StyleDavid Geisler-Moroder; Eleanor S. Lee; Gregory Ward; Bruno Bueno; Lars O. Grobe; Taoning Wang; Bertrand Deroisy; Helen Rose Wilson. 2021. "BSDF Generation Procedures for Daylighting Systems." BSDF Generation Procedures for Daylighting Systems , no. : 1.
A novel façade element is presented that forms a symbiosis between an enhanced box-type window, a closed cavity façade, and a Trombe wall. This hybrid, transparent-opaque façade element features an absorbing water tank, that is installed behind a controlled shading device toward the cavity of a non-ventilated Double Skin Façade in the parapet section. To evaluate the potential impact on building performance, a transient simulation model is developed in Modelica and calibrated by comparison with measurements on a prototype. The effect of the absorbing thermal storage on heat transfers under solar radiation is analyzed in comparison to (i) conditions excluding solar radiation and (ii) an empty tank. An evaluation for four European cities demonstrates that the annual heating demand can be reduced by more than 4.2% and cooling demand by at least 6.6% compared to a façade without thermal storage. The effect is explained not only by the increased thermal mass, but also by the effective modulation of solar gains by the controlled absorbing storage. The dampening of heat flow fluctuations and the control of solar gains is a promising means to reduce the installed power of HVAC (heating/ventilating/air conditioning) installations.
Thomas Wüest; Lars Grobe; Andreas Luible. An Innovative Façade Element with Controlled Solar-Thermal Collector and Storage. Sustainability 2020, 12, 5281 .
AMA StyleThomas Wüest, Lars Grobe, Andreas Luible. An Innovative Façade Element with Controlled Solar-Thermal Collector and Storage. Sustainability. 2020; 12 (13):5281.
Chicago/Turabian StyleThomas Wüest; Lars Grobe; Andreas Luible. 2020. "An Innovative Façade Element with Controlled Solar-Thermal Collector and Storage." Sustainability 12, no. 13: 5281.
With the advent of window glass, its optical properties arise as one important factor in the illumination, and thereby the visual perception, of Roman architecture. Computational simulation allows to reconstruct the daylight illumination of buildings with known geometrical configuration if the scattering properties of window glass can be replicated. We describe a method to generate data-driven models of Roman window glass based on precise gonio-photometric measurements of archaeological finds. The method is employed to model four exemplary glass finds in the context of a simplified architectural scene, demonstrating the potential to support research in building history and archaeology focused on building techniques, lighting concepts, and perception with accurate and reliable photometric data.
Lars Oliver Grobe; Andreas Noback; Franziska Lang. Data-Driven Modelling of Daylight Scattering by Roman Window Glass. Journal on Computing and Cultural Heritage 2020, 13, 1 -20.
AMA StyleLars Oliver Grobe, Andreas Noback, Franziska Lang. Data-Driven Modelling of Daylight Scattering by Roman Window Glass. Journal on Computing and Cultural Heritage. 2020; 13 (1):1-20.
Chicago/Turabian StyleLars Oliver Grobe; Andreas Noback; Franziska Lang. 2020. "Data-Driven Modelling of Daylight Scattering by Roman Window Glass." Journal on Computing and Cultural Heritage 13, no. 1: 1-20.
Stephen Wasilewski; Lars Oliver Grobe; Jan Wienold; Marilyne Andersen. A critical literature review of spatio-temporal simulation methods for daylight glare assessment. 2019, 7, 1 .
AMA StyleStephen Wasilewski, Lars Oliver Grobe, Jan Wienold, Marilyne Andersen. A critical literature review of spatio-temporal simulation methods for daylight glare assessment. . 2019; 7 (1):1.
Chicago/Turabian StyleStephen Wasilewski; Lars Oliver Grobe; Jan Wienold; Marilyne Andersen. 2019. "A critical literature review of spatio-temporal simulation methods for daylight glare assessment." 7, no. 1: 1.
Data-driven modelling provides a general means to represent optically complex fenestration in daylight simulation by its Bidirectional Scattering Distribution Function (BSDF). Radiance employs the tensor tree as a compact data structure to store the BSDF at high directional resolution. The application of such models under sunny sky conditions is, however, computationally demanding, since the density of stochastic backward samples must match the BSDF resolution. The bidirectional Photon Map is proposed to rapidly forward-sample the BSDF, starting from the known sun direction. Its exemplary application shows a potential speed-up of ≥ 98% when compared to backward ray-tracing.
Lars O Grobe. Photon mapping to accelerate daylight simulation with high-resolution, data-driven fenestration models. Journal of Physics: Conference Series 2019, 1343, 012154 .
AMA StyleLars O Grobe. Photon mapping to accelerate daylight simulation with high-resolution, data-driven fenestration models. Journal of Physics: Conference Series. 2019; 1343 (1):012154.
Chicago/Turabian StyleLars O Grobe. 2019. "Photon mapping to accelerate daylight simulation with high-resolution, data-driven fenestration models." Journal of Physics: Conference Series 1343, no. 1: 012154.
Visual comfort assessments employing luminance-based metrics rely on efficient CBDM techniques for image synthesis. Data-driven BSDF models allow to isolate internal light paths in optically CFS from CBDM. Bidirectional photon mapping is proposed for the efficient sampling of such models in the calculation of the direct solar component in CBDM. The method allows accurate image synthesis for visual comfort assessments with only two calculation steps, achieving comparable accuracy as the established but complex 5PM. The validity of the approach is confirmed by comparison with backward ray-tracing. Its exemplary application to compare two CFS in terms of glare control demonstrates the importance to achieve reconcilability of conflicting targets such as view and glare control in daylighting.
Lars Oliver Grobe. Photon-mapping in Climate-Based Daylight Modelling with High-resolution BSDFs. Energy and Buildings 2019, 205, 109524 .
AMA StyleLars Oliver Grobe. Photon-mapping in Climate-Based Daylight Modelling with High-resolution BSDFs. Energy and Buildings. 2019; 205 ():109524.
Chicago/Turabian StyleLars Oliver Grobe. 2019. "Photon-mapping in Climate-Based Daylight Modelling with High-resolution BSDFs." Energy and Buildings 205, no. : 109524.
Data-driven models replicate the irregular Bidirectional Scattering Distribution Functions (BSDFs) of optically Complex Fenestration Systems in daylight simulation. RADIANCE employs the tensor tree to store the BSDF at high directional resolution. Its application in backward ray-tracing is however challenging, since the density of stochastic samples must match the model resolution. BSDF proxy and peak extraction address this problem, but are limited to cases when either the fenestration geometry, or the shape and direction of the transmission peak are known. Photon Mapping is proposed to efficiently sample arbitrary BSDFs from the known sun direction. The existing implementation in RADIANCE is extended to account for light sources and their reflections in the field of view, that are of particular importance for visual comfort assessments. The method achieves a high degree of accordance with ray-tracing, and reduces simulation times by ≈95% with data-driven models of high resolution. Abbreviations: BRT: Backward Ray-Tracing; BSDF: Bidirectional Scattering Distribution Function; CBDM: Climate-Based Daylight Modelling; CFS: Complex Fenestration System; DGI: Daylight Glare Index; DGP: Daylight Glare Probability; FPM: Five Phase Method; GPGPU: General Purpose Graphics Processing Unit; LCP: Laser Cut Panel; OoC: Out-of-Core; PM: Photon Mapping; RMSE: Root Mean Squared Error
Lars O. Grobe. Photon mapping in image-based visual comfort assessments with BSDF models of high resolution. Journal of Building Performance Simulation 2019, 12, 745 -758.
AMA StyleLars O. Grobe. Photon mapping in image-based visual comfort assessments with BSDF models of high resolution. Journal of Building Performance Simulation. 2019; 12 (6):745-758.
Chicago/Turabian StyleLars O. Grobe. 2019. "Photon mapping in image-based visual comfort assessments with BSDF models of high resolution." Journal of Building Performance Simulation 12, no. 6: 745-758.
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.
Lars O. Grobe. Characterization and data-driven modeling of a retro-reflective coating in Radiance. Energy and Buildings 2017, 162, 121 -133.
AMA StyleLars O. Grobe. Characterization and data-driven modeling of a retro-reflective coating in Radiance. Energy and Buildings. 2017; 162 ():121-133.
Chicago/Turabian StyleLars O. Grobe. 2017. "Characterization and data-driven modeling of a retro-reflective coating in Radiance." Energy and Buildings 162, no. : 121-133.
Lars O. Grobe; Tuğçe KAZANASMAZ; Burçin Hanci Geçit; Zeynep Sevinç; Gülce Altinkaya; Gizem Aksakarya; Meltem Ergin; Yasemin Öztürk. Scale-Model And Simulation-Based Assessments For Design Alternatives Of Daylight Redirecting Systems In A Side-Lighting Educational Room. METU JOURNAL OF THE FACULTY OF ARCHITECTURE 2017, 1 .
AMA StyleLars O. Grobe, Tuğçe KAZANASMAZ, Burçin Hanci Geçit, Zeynep Sevinç, Gülce Altinkaya, Gizem Aksakarya, Meltem Ergin, Yasemin Öztürk. Scale-Model And Simulation-Based Assessments For Design Alternatives Of Daylight Redirecting Systems In A Side-Lighting Educational Room. METU JOURNAL OF THE FACULTY OF ARCHITECTURE. 2017; ():1.
Chicago/Turabian StyleLars O. Grobe; Tuğçe KAZANASMAZ; Burçin Hanci Geçit; Zeynep Sevinç; Gülce Altinkaya; Gizem Aksakarya; Meltem Ergin; Yasemin Öztürk. 2017. "Scale-Model And Simulation-Based Assessments For Design Alternatives Of Daylight Redirecting Systems In A Side-Lighting Educational Room." METU JOURNAL OF THE FACULTY OF ARCHITECTURE , no. : 1.
Marek Krehel; Lars O. Grobe; Stephen Wittkopf. A hybrid data-driven BSDF model to predict light transmission through complex fenestration systems including high incident directions. Journal of Facade Design and Engineering 2017, 4, 79 -89.
AMA StyleMarek Krehel, Lars O. Grobe, Stephen Wittkopf. A hybrid data-driven BSDF model to predict light transmission through complex fenestration systems including high incident directions. Journal of Facade Design and Engineering. 2017; 4 (3-4):79-89.
Chicago/Turabian StyleMarek Krehel; Lars O. Grobe; Stephen Wittkopf. 2017. "A hybrid data-driven BSDF model to predict light transmission through complex fenestration systems including high incident directions." Journal of Facade Design and Engineering 4, no. 3-4: 79-89.
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.
Lars Oliver Grobe. Computational Combination of the Optical Properties of Fenestration Layers at High Directional Resolution. Buildings 2017, 7, 22 .
AMA StyleLars Oliver Grobe. Computational Combination of the Optical Properties of Fenestration Layers at High Directional Resolution. Buildings. 2017; 7 (4):22.
Chicago/Turabian StyleLars Oliver Grobe. 2017. "Computational Combination of the Optical Properties of Fenestration Layers at High Directional Resolution." Buildings 7, no. 4: 22.
For the systematic development of a small-scale daylight-redirecting louver system the impact of manufacturing on light scattering characteristics has to be quantified, localized and understood. In this research, the accordance of the measured scattering distributions of a de-facto production sample V1 with the computed predictions based on its design geometry V2 are quantified for selected incident light directions. A metric describing the global accordance of distributions is adapted to quantify their overall difference. A novel metric of local accordance allows further analysis. A particular low global accordance between V1 and V2 is found for an incident elevation θi=35∘. To test the hypothesis that this result can be explained by observed geometric deviations, a simulation model V3 replicating these is compared to the design. The hypothesis is supported by the resulting high degree of accordance. The low local accordance for individual outgoing light directions indicates geometric non-uniformity of the sample V1. This method has been found useful for product development and quality assurance. Beyond their application in the proposed method, global and local accordance have potential applications in all fields of light scattering measurements.
Andreas Noback; Lars O. Grobe; Stephen Wittkopf. Accordance of Light Scattering from Design and De-Facto Variants of a Daylight Redirecting Component. Buildings 2016, 6, 30 .
AMA StyleAndreas Noback, Lars O. Grobe, Stephen Wittkopf. Accordance of Light Scattering from Design and De-Facto Variants of a Daylight Redirecting Component. Buildings. 2016; 6 (3):30.
Chicago/Turabian StyleAndreas Noback; Lars O. Grobe; Stephen Wittkopf. 2016. "Accordance of Light Scattering from Design and De-Facto Variants of a Daylight Redirecting Component." Buildings 6, no. 3: 30.
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.
Tuğçe Kazanasmaz; Lars Oliver Grobe; Carsten Bauer; Marek Krehel; Stephen Wittkopf. Three approaches to optimize optical properties and size of a South-facing window for spatial Daylight Autonomy. Building and Environment 2016, 102, 243 -256.
AMA StyleTuğçe Kazanasmaz, Lars Oliver Grobe, Carsten Bauer, Marek Krehel, Stephen Wittkopf. Three approaches to optimize optical properties and size of a South-facing window for spatial Daylight Autonomy. Building and Environment. 2016; 102 ():243-256.
Chicago/Turabian StyleTuğçe Kazanasmaz; Lars Oliver Grobe; Carsten Bauer; Marek Krehel; Stephen Wittkopf. 2016. "Three approaches to optimize optical properties and size of a South-facing window for spatial Daylight Autonomy." Building and Environment 102, no. : 243-256.
Roland Schregle; Lars Oliver Grobe; S. Wittkopf. An out-of-core photon mapping approach to daylight coefficients. Journal of Building Performance Simulation 2016, 9, 620 -632.
AMA StyleRoland Schregle, Lars Oliver Grobe, S. Wittkopf. An out-of-core photon mapping approach to daylight coefficients. Journal of Building Performance Simulation. 2016; 9 (6):620-632.
Chicago/Turabian StyleRoland Schregle; Lars Oliver Grobe; S. Wittkopf. 2016. "An out-of-core photon mapping approach to daylight coefficients." Journal of Building Performance Simulation 9, no. 6: 620-632.
Daylight redirecting components (DRCs) are characterised by complex transmissive and reflective behaviour that is difficult to predict accurately largely due to their highly directional scattering, and the caustics this produces. This paper examines the application of progressive photon mapping as a state of the art forward raytracing technique to efficiently simulate the behaviour of such DRCs, and how this approach can support architects in assessing their performance. Progressive photon mapping is an iterative variant of static photon mapping that effects noise reduction through accumulation of results, as well as a reduction in bias inherent to all density estimation methods by reducing the associated bandwidth at a predetermined rate. This not only results in simplified parametrisation for the user, but also provides a preview of the progressively refined simulation, thus making the tool accessible to non-experts as well. We demonstrate the effectiveness of this technique with an implementation based on the Radiance photon mapping extension and a case study involving retroreflecting prismatic blinds as a representative DRC.
R. Schregle; L. Grobe; S. Wittkopf. Progressive photon mapping for daylight redirecting components. Solar Energy 2015, 114, 327 -336.
AMA StyleR. Schregle, L. Grobe, S. Wittkopf. Progressive photon mapping for daylight redirecting components. Solar Energy. 2015; 114 ():327-336.
Chicago/Turabian StyleR. Schregle; L. Grobe; S. Wittkopf. 2015. "Progressive photon mapping for daylight redirecting components." Solar Energy 114, no. : 327-336.
The church of Hagia Sophia – from the Greek: □γία Σοϕία, “Holy Wisdom” – built on the orders of Emperor Justinianis from 532 to 537 (AD) is the most important building of an era which is generally characterised as the decline of the ancient world and the beginning of the mediaeval times. The building is well considered to be one of the most outstanding masterpieces of architecture in the world having an extensive influence on European and islamic architecture in general.
Oliver Hauck; Andreas Noback; Lars Oliver Grobe. Computing the “Holy Wisdom”. Contributions in Mathematical and Computational Sciences 2012, 3, 205 -216.
AMA StyleOliver Hauck, Andreas Noback, Lars Oliver Grobe. Computing the “Holy Wisdom”. Contributions in Mathematical and Computational Sciences. 2012; 3 ():205-216.
Chicago/Turabian StyleOliver Hauck; Andreas Noback; Lars Oliver Grobe. 2012. "Computing the “Holy Wisdom”." Contributions in Mathematical and Computational Sciences 3, no. : 205-216.
This paper presents a novel method to study how well non-imaging daylight collectors pipe diffuse daylight into long horizontal funnels for illuminating deep buildings. Forward ray tracing is used to derive luminous intensity distributions curves (LIDC) of such collectors centered in an arc-shaped light source representing daylight. New photometric characteristics such as 2D flux, angular spread and horizontal offset are introduced as a function of such LIDC. They are applied for quantifying and thus comparing different collector contours.
Stephen Wittkopf; Lars Oliver Grobe; David Geisler-Moroder; Raphaël Compagnon; Jérôme Kämpf; Friedrich Linhart; Jean-Louis Scartezzini. Ray tracing study for non-imaging daylight collectors. Solar Energy 2010, 84, 986 -996.
AMA StyleStephen Wittkopf, Lars Oliver Grobe, David Geisler-Moroder, Raphaël Compagnon, Jérôme Kämpf, Friedrich Linhart, Jean-Louis Scartezzini. Ray tracing study for non-imaging daylight collectors. Solar Energy. 2010; 84 (6):986-996.
Chicago/Turabian StyleStephen Wittkopf; Lars Oliver Grobe; David Geisler-Moroder; Raphaël Compagnon; Jérôme Kämpf; Friedrich Linhart; Jean-Louis Scartezzini. 2010. "Ray tracing study for non-imaging daylight collectors." Solar Energy 84, no. 6: 986-996.
The development of advanced materials for facades aims to achieve higher energy efficiency of buildings. Successful application of these materials depends on the availability of reliable characterization data. While data derived from integrated measurements of transmission and reflection is widely available, it does not allow to characterize the angular dependence of the performance of such materials. The Bidirectional Reflection-Transmission Distribution (BRTD) can be measured by commercially available Gonio-Photometers and, complimenting integrated transmittance and reflectance, allows the assessment of facade materials and thus supports both their development and application. Validation of the obtained data is crucial to back these measurements. Integration of validation procedures into the operation of a characterization laboratory allowing a well-defined approach to quality control is presented for a range of typical material and sample types: * consistency checks of measurement data * cross-checking of integrated material properties derived from BRTD data with integrating sphere measurements * round-robin comparison between laboratories using comparable devices The results of of these first measurements are discussed. Potential to further improve the availability of reliable angular resolved characterization data for the building sector is identified.
Lars Oliver Grobe; Stephen Wittkopf; Peter Apian-Bennewitz; Jacob C. Jonsson; Mike Rubin. Experimental validation of bidirectional reflection and transmission distribution measurements of specular and scattering materials. Photonics Europe 2010, 7725, 772510 .
AMA StyleLars Oliver Grobe, Stephen Wittkopf, Peter Apian-Bennewitz, Jacob C. Jonsson, Mike Rubin. Experimental validation of bidirectional reflection and transmission distribution measurements of specular and scattering materials. Photonics Europe. 2010; 7725 ():772510.
Chicago/Turabian StyleLars Oliver Grobe; Stephen Wittkopf; Peter Apian-Bennewitz; Jacob C. Jonsson; Mike Rubin. 2010. "Experimental validation of bidirectional reflection and transmission distribution measurements of specular and scattering materials." Photonics Europe 7725, no. : 772510.