Field validation of data-driven BSDF and peak extraction models for light-scattering fabric shades

Shading and daylighting systems affect cooling, heating, and lighting energy use by modulating solar radiation through the building façade. Characterizing shading systems holistically and accurately helps designers and engineers evaluate shading systems to achieve energy and non-energy performance g...

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Vydáno v:Energy and buildings Ročník 262; s. 112002
Hlavní autoři: Wang, Taoning, Lee, Eleanor S., Ward, Gregory J., Yu, Tammie
Médium: Journal Article
Jazyk:angličtina
Vydáno: Lausanne Elsevier B.V 01.05.2022
Elsevier BV
Elsevier
Témata:
Accuracy
Adaptation
Algorithms
Angular resolution
Bidirectional scattering distribution function
Building energy efficiency
Complex fenestration systems
Data reduction
Daylighting
Discomfort glare
Distribution functions
Energy
ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
Energy consumption
Fabrics
Field of view
Glare
Illuminance
Incident radiation
Interpolation
Luminance
Mathematical analysis
Radiation
Ray tracing
Scattering
Shades
Shading
Solar energy
Solar radiation
Systems analysis
Tensors
Textiles
Windows
Workflow
Bidirectional scattering distribution function
Daylighting
Complex fenestration systems
Fabrics
Windows
Building energy efficiency
Textiles
Discomfort glare
ISSN:0378-7788, 1872-6178
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Shrnutí:Shading and daylighting systems affect cooling, heating, and lighting energy use by modulating solar radiation through the building façade. Characterizing shading systems holistically and accurately helps designers and engineers evaluate shading systems to achieve energy and non-energy performance goals. These complex fenestration systems can be modeled using Bidirectional Scattering Distribution Functions (BSDF), which map incident radiation to hemispherical distributions of outgoing radiation. Data-driven, tabulated BSDFs are derived from interpolated goniophotometer measured data, then sampled during the raytracing calculation. A peak extraction (PE) algorithm was developed to circumvent limits in BSDF angular resolution, where the specular peak is extracted during simulation by evaluating the BSDF in the through direction and surrounding region. The objective of this study was to validate this measurement and modeling workflow using field monitored data from a full scale testbed with eleven installed fabrics of different weaves, openness factors, and colors and assess the accuracy of the workflow under different adaptation and contrast conditions. Test conditions were limited to clear sky conditions with the sun in the field of view. Results showed that, for tensor tree datasets, vertical illuminance, solar luminance (2.5° apex), and daylight glare probability (DGP) were predicted to within a mean bias error (MBE) error of −456 lx (−12.3%), −3.46e5 (−38.4%), and −0.042 (−7.8%) when full PE occurred. With a binary classification of glare/ no glare, DGP was predicted accurately with a true positive rate of 0.98 and true negative rate of 1.0 using tensor tree data and less accurately with Klems BSDF data, particularly for cases of no glare. The workflow may be of insufficient accuracy to distinguish borderline performance between fabrics using the four-point glare scale, particularly under low adaptation, high contrast daylit conditions. Errors were due to reductions in peak shape and intensity across the BSDF interpolation and data reduction workflow. Future work is needed to better preserve measurement fidelity during interpolation and sampling, which in turn will improve PE performance.
Bibliografie:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 14
AC02-05CH11231
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office
ISSN:0378-7788
1872-6178
DOI:10.1016/j.enbuild.2022.112002