Evaluation of radiance's <i>genBSDF</i> capability to assess solar bidirectional properties of complex fenestration systems

Molina, Germán; Bustamante, Waldo; Rao, Jiwu; Fazio, Paul; Vera, Sergio

doi:10.1080/19401493.2014.912355

Cited by 34 publications

(9 citation statements)

References 14 publications

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“…Conclusions of these studies are based on daylighting and thermal performance simulations. No experimental studies exist in Chile regarding to thermal and daylighting performance of complex fenestration systems, which includes glazing and shading devices with complex geometries (such as perforated screens, blinds, and curtain rollers) with optical properties highly angular dependent [29]. These types of complex systems are difficult or impossible to be modeled in a simulation tool.…”

Section: Introductionmentioning

confidence: 99%

Solar and Lighting Transmission through Complex Fenestration Systems of Office Buildings in a Warm and Dry Climate of Chile

et al. 2014

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Overheating, glare, and high-energy demand are recurrent problems in office buildings in Santiago, Chile (33°27'S; 70°42'W) during cooling periods. Santiago climate is warm and dry, with high solar radiation and temperature during most of the year. The objective of this paper is to evaluate the thermal and daylighting performance of office buildings transparent faç ades composed of three different complex fenestration systems (CFS). Each CFS contains a different external shading device (ESD): (1) external roller, (2) vertical undulated and perforated screens, and (3) tilted undulated and perforated screens. The study was carried out by in situ monitoring in three office buildings in Santiago, Chile. Buildings were selected from a database of 103 buildings, representing those constructed between 2005 and 2011 in the city. The monitoring consisted of measuring the short wave solar and daylighting transmission through fenestration systemsby means of pyranometers and luxometers, respectively. This paper shows measurements that were carried out during summer period. A good performance is observed in a building with the external roller system. This system-applied to a northwest faç ade-shows a regular and high solar and daylighting control of incoming solar radiation. OPEN ACCESSSustainability 2014, 6 2787The other two ESD systems evidence a general good performance. However, some deficiencies at certain times of the day were detected, suggesting a non-appropriated design.

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Section: Introductionmentioning

confidence: 99%

Solar and Lighting Transmission through Complex Fenestration Systems of Office Buildings in a Warm and Dry Climate of Chile

et al. 2014

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“…Use of such tools may be the only option in cases where the material properties or fenestration system has a scale that is too large to be measured within the narrow beam diameter of the goniophotometer (e.g., repeating elements of a louver system). An open source, ray-tracing tool called genBSDF [Radiance 2010] was developed for this purpose and validated using simulated and field measured data , Molina et al 2015. genBSDF uses a geometric model and transmittance and/or reflectance properties of the basic materials that make up the fenestration system to generate a full BSDF.…”

Section: Generating Bsdfs Using a Geometric Model And Materials Propermentioning

confidence: 99%

Modeling the direct sun component in buildings using matrix algebraic approaches: Methods and validation

Lee

Geisler‐Moroder

Ward³

2018

Solar Energy

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Simulation tools that enable annual energy performance analysis of optically-complex fenestration systems have been widely adopted by the building industry for use in building design, code development, and the development of rating and certification programs for commercially-available shading and daylighting products. The tools rely on a three-phase matrix operation to compute solar heat gains, using as input lowresolution bidirectional scattering distribution function (BSDF) data (10-15° angular resolution; BSDF data define the angle-dependent behavior of light-scattering materials and systems). Measurement standards and product libraries for BSDF data are undergoing development to support solar heat gain calculations. Simulation of other metrics such as discomfort glare, annual solar exposure, and potentially thermal discomfort, however, require algorithms and BSDF input data that more accurately model the spatial distribution of transmitted and reflected irradiance or illuminance from the sun (0.5° resolution).This study describes such algorithms and input data, then validates the tools (i.e., an interpolation tool for measured BSDF data and the five-phase method) through comparisons with ray-tracing simulations and field monitored data from a full-scale testbed. Simulations of daylight-redirecting films, a micro-louvered screen, and venetian blinds using variable resolution, tensor tree BSDF input data derived from interpolated scanning goniophotometer measurements were shown to agree with field monitored data to within 20% for greater than 75% of the measurement period for illuminance-based performance parameters. The threephase method delivered significantly less accurate results. We discuss the ramifications of these findings on industry and provide recommendations to increase end user awareness of the current limitations of existing software tools and BSDF product libraries.

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“…With the scanned detail structure and dimension information, the detailed PDRF geometry model can be built up with the Rhino program, and then the Bidirectional Scattering Distribution Function of the CFS daylight characteristics can be generated using the Radiance genBSDF module, which has been validated by several studies. 14,17,29 With genBSDF , one can output .xml files, which can be read and presented with BSDFViewer . 30 Figure 8 illustrates the incident light and outgoing flux scattering distribution for prism film and prism film plus diffusing layer from BSDFViewer .…”

Section: Methodsmentioning

confidence: 99%

A study of luminous environment with prism daylight redirecting fenestrations in classrooms

Tian

Lin

et al. 2020

Indoor and Built Environment

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This study explored the classroom luminous environment with prism daylight redirecting fenestrations. The differences between the International Commission on Illumination standard sky and the Perez all-weather sky models were analysed. The study described the method of generating a valid bi-directional scattering distribution functions .xml data for the prism daylight redirecting fenestrations. A new evaluation metric, daylight evenness, was proposed to describe indoor illuminance dispersion. Radiance simulation results indicate that at various solar altitude angles, compared with conventional glazing, the micro-prism film and micro-prism with an added diffuse layer on clerestories can improve the space average illuminance levels 23.2% and 18.7% under the International Commission on Illumination sky, as well as 15.4% and 10.6% under the Perez sky, respectively. The analysis results indicate that prism daylight redirecting fenestrations clerestories can improve indoor illuminance uniformity and daylight evenness when the solar altitudes range from 23.8° to 75°. A method combined field questionnaire and high dynamic range image analysis were conducted for discomfort glare study. Adding a diffused layer to the prism film clerestory is expected to alleviate discomfort glare for east- and west-facing prism daylight redirecting fenestrations clerestory with the daylight glare probability reduction of 3.8% to 21.7% at various solar altitudes. The research results present promising advantages of applying prism daylight redirecting fenestrations at classroom clerestories to improve the daylight luminous environment.

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Evaluation of radiance's genBSDF capability to assess solar bidirectional properties of complex fenestration systems

Cited by 34 publications

References 14 publications

Solar and Lighting Transmission through Complex Fenestration Systems of Office Buildings in a Warm and Dry Climate of Chile

Solar and Lighting Transmission through Complex Fenestration Systems of Office Buildings in a Warm and Dry Climate of Chile

Modeling the direct sun component in buildings using matrix algebraic approaches: Methods and validation

A study of luminous environment with prism daylight redirecting fenestrations in classrooms

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