Please use this identifier to cite or link to this item:
http://hdl.handle.net/10397/78287
Title: | The impact of room surface reflectance on corneal illuminance and rule-of-thumb equations for circadian lighting design | Authors: | Cai, WJ Yue, JG Dai, Q Hao, LX Lin, Y Shi, W Huang, YY Wei, MC |
Issue Date: | 2018 | Source: | Building and environment, 15 Aug. 2018, v. 141, p. 288-297 | Abstract: | Recently, corneal illuminance attracts much attention because it is closely related to important functions of indoor lighting. Especially, applying circadian light in the built environment places a challenging requirement on indirect corneal illuminance. In this work, rule-of-thumb equations are proposed to guide circadian lighting design: (i) for artificial lighting, E-cor,E-avg ((i)) = (Phi/C-1). rho/(1-rho'), where E-cor,E-avg (i) is the average indirect corneal illuminance at standing or sitting positions, Phi is the initial flux from luminaires, C-1 is a constant comparable to the total room surface area, rho is the reflectance of the surface where the first reflection occurs, and rho' is the area weighted average of surface reflectance; and (ii) for daylighting, E-cor,E-avg (i) = C-2 . WWR . rho/(1-rho'), where C-2 is a constant, and WWR represents the window-to-wall ratio. The equations above are validated by comparing against numerical simulation data obtained with the Radiance software. For artificial lighting simulation, various combinations of room surface reflectance, initial light distribution, and WWR are investigated; and for daylighting simulation, different combinations of surface reflectance, WWR, and geographic location are analyzed. The good fits to simulation data indicate that the proposed simple equations can provide reasonably accurate results for quick feedback at the field. It is also demonstrated that room surface reflectance has a dominant impact on indirect corneal illuminance. The approach of improving surface reflectance is more favorable than increasing luminaire flux or expanding window area, and therefore should be the recommended approach to achieve quality and efficient circadian lighting. | Keywords: | Corneal illuminance Surface reflectance Circadian lighting Daylight Lighting quality |
Publisher: | Pergamon Press | Journal: | Building and environment | ISSN: | 0360-1323 | EISSN: | 1873-684X | DOI: | 10.1016/j.buildenv.2018.05.056 | Rights: | © 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/) The following publication Cai, W., Yue, J., Dai, Q., Hao, L., Lin, Y., Shi, W., . . . Wei, M. (2018). The impact of room surface reflectance on corneal illuminance and rule-of-thumb equations for circadian lighting design. Building and Environment, 141, 288-297 is available at https://dx.doi.org/10.1016/j.buildenv.2018.05.056 |
Appears in Collections: | Journal/Magazine Article |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
Cai_Room_Corneal_Illuminance.pdf | 2.86 MB | Adobe PDF | View/Open |
Page views
200
Last Week
1
1
Last month
Citations as of Apr 14, 2024
Downloads
202
Citations as of Apr 14, 2024
SCOPUSTM
Citations
57
Citations as of Apr 19, 2024
WEB OF SCIENCETM
Citations
49
Last Week
0
0
Last month
Citations as of Apr 18, 2024
Google ScholarTM
Check
Altmetric
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.