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The effects of direct sunlight on light shelf performance under tropical sky

As daylight is dynamic, there is no one common solution for all scenarios. Understanding of sky conditions is the fundamental to effective daylighting. It is more critical in tropical climate where the sky is predominantly intermediate with inconsistent presence of direct sunlight (DSL). Thereby, da...

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Main Authors: Lim, Yaik-Wah, Ahmad, Mohd Hamdan
Format: Article
Published: SAGE Publications Ltd 2015
Subjects:
NA9000-9284 City planning
Online Access:http://eprints.utm.my/id/eprint/58930/
http://dx.doi.org/10.1177/1420326X14536066
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spelling my.utm.589302021-09-02T12:49:04Z http://eprints.utm.my/id/eprint/58930/ The effects of direct sunlight on light shelf performance under tropical sky Lim, Yaik-Wah Ahmad, Mohd Hamdan NA9000-9284 City planning As daylight is dynamic, there is no one common solution for all scenarios. Understanding of sky conditions is the fundamental to effective daylighting. It is more critical in tropical climate where the sky is predominantly intermediate with inconsistent presence of direct sunlight (DSL). Thereby, daylighting performances of several light shelf configurations were experimented with physical scaled model under actual tropical sky conditions. External illuminance and indoor work plane illuminance (WPI) levels were measured concurrently in a reference model and a test model for comparisons. Daylight ratio or daylight factor and WPI uniformity ratio were computed for analysis. From the results, different optimum cases were identified for various sky conditions. Light shelves performed the best under intermediate sky with DSL from low angle. The highest improvement in WPI at deep room area and WPI uniformity were 24.87% and 364.96%, respectively. The performances of light shelves under overcast sky were better than light shelf under intermediate sky without DSL. This paper concluded that designing light shelf by responding to changeable sky conditions and DSL is more crucial than considering the façade orientations. Dynamic light shelf was proposed to configure the optimum cases for each tropical sky conditions. SAGE Publications Ltd 2015 Article PeerReviewed Lim, Yaik-Wah and Ahmad, Mohd Hamdan (2015) The effects of direct sunlight on light shelf performance under tropical sky. Indoor And Built Environment, 24 (6). pp. 788-802. ISSN 1420-326X http://dx.doi.org/10.1177/1420326X14536066 10.1177/1420326X14536066
institution Universiti Teknologi Malaysia
building UTM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknologi Malaysia
content_source UTM Institutional Repository
url_provider http://eprints.utm.my/
topic NA9000-9284 City planning
spellingShingle NA9000-9284 City planning
Lim, Yaik-Wah
Ahmad, Mohd Hamdan
The effects of direct sunlight on light shelf performance under tropical sky
description As daylight is dynamic, there is no one common solution for all scenarios. Understanding of sky conditions is the fundamental to effective daylighting. It is more critical in tropical climate where the sky is predominantly intermediate with inconsistent presence of direct sunlight (DSL). Thereby, daylighting performances of several light shelf configurations were experimented with physical scaled model under actual tropical sky conditions. External illuminance and indoor work plane illuminance (WPI) levels were measured concurrently in a reference model and a test model for comparisons. Daylight ratio or daylight factor and WPI uniformity ratio were computed for analysis. From the results, different optimum cases were identified for various sky conditions. Light shelves performed the best under intermediate sky with DSL from low angle. The highest improvement in WPI at deep room area and WPI uniformity were 24.87% and 364.96%, respectively. The performances of light shelves under overcast sky were better than light shelf under intermediate sky without DSL. This paper concluded that designing light shelf by responding to changeable sky conditions and DSL is more crucial than considering the façade orientations. Dynamic light shelf was proposed to configure the optimum cases for each tropical sky conditions.
format Article
author Lim, Yaik-Wah
Ahmad, Mohd Hamdan
author_facet Lim, Yaik-Wah
Ahmad, Mohd Hamdan
author_sort Lim, Yaik-Wah
title The effects of direct sunlight on light shelf performance under tropical sky
title_short The effects of direct sunlight on light shelf performance under tropical sky
title_full The effects of direct sunlight on light shelf performance under tropical sky
title_fullStr The effects of direct sunlight on light shelf performance under tropical sky
title_full_unstemmed The effects of direct sunlight on light shelf performance under tropical sky
title_sort effects of direct sunlight on light shelf performance under tropical sky
publisher SAGE Publications Ltd
publishDate 2015
url http://eprints.utm.my/id/eprint/58930/
http://dx.doi.org/10.1177/1420326X14536066
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score 13.211869

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