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Advances in Civil Engineering
Volume 2018, Article ID 2028065, 9 pages
Research Article

Development and Performance Evaluation of Light Shelves Using Width-Adjustable Reflectors

1The Graduate School of Techno Design, Kookmin University, Seoul 02707, Republic of Korea
2Department of Architecture, Graduated School, Kookmin University, Seoul 02707, Republic of Korea
3School of Architecture, Kookmin University, Seoul 02707, Republic of Korea

Correspondence should be addressed to Janghoo Seo;

Received 11 December 2017; Accepted 29 January 2018; Published 1 April 2018

Academic Editor: Geun Y. Yun

Copyright © 2018 Heangwoo Lee et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In recent years, there has been an increase in the consumption of energy for lighting purposes, which has led to an increase in the number of studies being conducted on this subject. Most studies have focused on light shelves, which are daylighting systems used for reducing the lighting energy required for the interiors of buildings. However, the existing light shelves cannot actively deal with external environmental factors, which often lead to an infringement of the right to light during the night when the performance of the light shelf deteriorates. Therefore, in this study, we propose a light shelf with a width-adjustable reflector and verify its validity using a testbed. The reflector of the proposed light shelf system is modularized so that the length can be adjusted in stages. The optimum width of the light shelf is calculated in terms of the energy reduction and uniformity ratio improvement, and the obtained optimum width is varied depending on the season. We find that the width-adjustable reflector can save 20% and 21.6% more lighting energy than light shelves with fixed reflector widths of 0.3 m and 0.6 m, respectively.