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Title: Modelling Complex Fenestration Systems using physical and virtual models

Abstract

Physical or virtual models are commonly used to visualize the conceptual ideas of architects, lighting designers and researchers; they are also employed to assess the daylighting performance of buildings, particularly in cases where Complex Fenestration Systems (CFS) are considered. Recent studies have however revealed a general tendency of physical models to over-estimate this performance, compared to those of real buildings; these discrepancies can be attributed to several reasons. In order to identify the main error sources, a series of comparisons in-between a real building (a single office room within a test module) and the corresponding physical and virtual models was undertaken. The physical model was placed in outdoor conditions, which were strictly identical to those of the real building, as well as underneath a scanning sky simulator. The virtual model simulations were carried out by way of the Radiance program using the GenSky function; an alternative evaluation method, named Partial Daylight Factor method (PDF method), was also employed with the physical model together with sky luminance distributions acquired by a digital sky scanner during the monitoring of the real building. The overall daylighting performance of physical and virtual models were assessed and compared. The causes of discrepancies between the daylightingmore » performance of the real building and the models were analysed. The main identified sources of errors are the reproduction of building details, the CFS modelling and the mocking-up of the geometrical and photometrical properties. To study the impact of these errors on daylighting performance assessment, computer simulation models created using the Radiance program were also used to carry out a sensitivity analysis of modelling errors. The study of the models showed that large discrepancies can occur in daylighting performance assessment. In case of improper mocking-up of the glazing for instance, relative divergences of 25-40% can be found in different room locations, suggesting that more light is entering than actually monitored in the real building. All these discrepancies can however be reduced by making an effort to carefully mock up the geometry and photometry of the real building. A synthesis is presented in this article which can be used as guidelines for daylighting designers to avoid or estimate errors during CFS daylighting performance assessment. (author)« less

Authors:
;  [1]
  1. Solar Energy and Building Physics Laboratory (LESO-PB), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)
Publication Date:
OSTI Identifier:
21305741
Resource Type:
Journal Article
Journal Name:
Solar Energy
Additional Journal Information:
Journal Volume: 84; Journal Issue: 4; Conference: International Conference CISBAT 2007; Other Information: Elsevier Ltd. All rights reserved; Journal ID: ISSN 0038-092X
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; COMPUTERIZED SIMULATION; DAYLIGHTING; BUILDINGS; PERFORMANCE; WINDOWS; ERRORS; COMPARATIVE EVALUATIONS; VISIBLE RADIATION; GLAZING MATERIALS; SCALE MODELS; OUTDOORS; CONFIGURATION; RECOMMENDATIONS; SENSITIVITY ANALYSIS; PHOTOMETRY; Virtual models

Citation Formats

Thanachareonkit, Anothai, and Scartezzini, Jean-Louis. Modelling Complex Fenestration Systems using physical and virtual models. United States: N. p., 2010. Web. doi:10.1016/J.SOLENER.2009.09.009.
Thanachareonkit, Anothai, & Scartezzini, Jean-Louis. Modelling Complex Fenestration Systems using physical and virtual models. United States. https://doi.org/10.1016/J.SOLENER.2009.09.009
Thanachareonkit, Anothai, and Scartezzini, Jean-Louis. 2010. "Modelling Complex Fenestration Systems using physical and virtual models". United States. https://doi.org/10.1016/J.SOLENER.2009.09.009.
@article{osti_21305741,
title = {Modelling Complex Fenestration Systems using physical and virtual models},
author = {Thanachareonkit, Anothai and Scartezzini, Jean-Louis},
abstractNote = {Physical or virtual models are commonly used to visualize the conceptual ideas of architects, lighting designers and researchers; they are also employed to assess the daylighting performance of buildings, particularly in cases where Complex Fenestration Systems (CFS) are considered. Recent studies have however revealed a general tendency of physical models to over-estimate this performance, compared to those of real buildings; these discrepancies can be attributed to several reasons. In order to identify the main error sources, a series of comparisons in-between a real building (a single office room within a test module) and the corresponding physical and virtual models was undertaken. The physical model was placed in outdoor conditions, which were strictly identical to those of the real building, as well as underneath a scanning sky simulator. The virtual model simulations were carried out by way of the Radiance program using the GenSky function; an alternative evaluation method, named Partial Daylight Factor method (PDF method), was also employed with the physical model together with sky luminance distributions acquired by a digital sky scanner during the monitoring of the real building. The overall daylighting performance of physical and virtual models were assessed and compared. The causes of discrepancies between the daylighting performance of the real building and the models were analysed. The main identified sources of errors are the reproduction of building details, the CFS modelling and the mocking-up of the geometrical and photometrical properties. To study the impact of these errors on daylighting performance assessment, computer simulation models created using the Radiance program were also used to carry out a sensitivity analysis of modelling errors. The study of the models showed that large discrepancies can occur in daylighting performance assessment. In case of improper mocking-up of the glazing for instance, relative divergences of 25-40% can be found in different room locations, suggesting that more light is entering than actually monitored in the real building. All these discrepancies can however be reduced by making an effort to carefully mock up the geometry and photometry of the real building. A synthesis is presented in this article which can be used as guidelines for daylighting designers to avoid or estimate errors during CFS daylighting performance assessment. (author)},
doi = {10.1016/J.SOLENER.2009.09.009},
url = {https://www.osti.gov/biblio/21305741}, journal = {Solar Energy},
issn = {0038-092X},
number = 4,
volume = 84,
place = {United States},
year = {Thu Apr 15 00:00:00 EDT 2010},
month = {Thu Apr 15 00:00:00 EDT 2010}
}