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User acceptance studies for LED office lighting: light spectrum and correlated colour temperature

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Bhusal, Pramod, Dr., Aalto University, Department of Electrical Engineering and Automation, Finland
dc.contributor.author Islam, Mohammad Shahidul
dc.date.accessioned 2015-03-05T10:00:37Z
dc.date.available 2015-03-05T10:00:37Z
dc.date.issued 2015
dc.identifier.isbn 978-952-60-6120-7 (electronic)
dc.identifier.isbn 978-952-60-6119-1 (printed)
dc.identifier.issn 1799-4942 (electronic)
dc.identifier.issn 1799-4934 (printed)
dc.identifier.issn 1799-4934 (ISSN-L)
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/15268
dc.description.abstract During the last decade, lighting technology based on light-emitting diodes (LEDs) has advanced rapidly and is paving the way for the application of LED lighting in offices. Two experiments were carried out to study user preference for different LED light spectra and correlated colour temperature (CCT), and to determine user acceptance for LED office lighting. In a lighting booth experiment, twenty one different LED spectral power distributions (SPDs) were realised considering colour quality scale (CQS) gamut area scale Qg, CQS Colour preference scale Qp, feeling of contrast index (FCI) along with the CIE colour rendering index (CRI) at the CCTs of 2700K, 4000K, and 6500K. The observers evaluated the lit scenes under different light spectra at 500 lux for different factors such as brightness, visual comfort, and pleasantness. The observers preferred the LED SPDs which had higher values of a reference-based metric (Qp) or higher values of an area-based metric (Qg). The chromaticity difference (Duv) values also influenced the user preference of the light spectra. The observer preferred the CCT of 4000K and 6500K to the CCT of 2700K at 500 lux. The findings of the lighting booth experiment were used as the base line for the office room experiment where six different LED SPDs were realised at the CCTs of 4000K and 6500K considering Qp, Qg, and FCI. The observers evaluated the lit environments under different SPDs for brightness, visual comfort, glare, and pleasantness of colour of light along with other lighting aspects at illuminance levels of 300 lux and 500 lux. At 4000K, the observers preferred the LED light spectra which had higher values of Qp and Qg to the fluorescent lamps in the office environment at 500 lux. The preferred LED SPDs had negative Duv values, whereas the fluorescent lamp had positive Duv values. The observers preferred the CCT of 4000K to 6500K, under which the observers felt more comfortable and found the colour of light more pleasant than under 6500K at 500 lux. It was also found that the lit environment should be able to provide good quality lighting for visibility and the observers should feel visually comfortable in that lit environment if the illuminance level is varied. The results indicate the need to develop LED light spectra for office lighting considering Qp and Qg with negative Duv values within the recommended limit. As the Duv values affected the observers' preferences, colour of white light should be characterised not only by CCT but also by Duv values. en
dc.format.extent 53 + app. 98
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher Aalto University en
dc.publisher Aalto-yliopisto fi
dc.relation.ispartofseries Aalto University publication series DOCTORAL DISSERTATIONS en
dc.relation.ispartofseries 33/2015
dc.relation.haspart [Publication 1]: Islam, M; Dangol, R; Hyvärinen, M; Bhusal, P; Puolakka, M; Halonen, L. 2013. Investigation of user preferences for LED lighting in terms of light spectrum. Lighting Research and Technology, volume 45, issue 6, pages 641-665. DOI: 10.1177/1477153513475913
dc.relation.haspart [Publication 2]: Dangol, R; Islam, M; Hyvärinen, M; Bhusal, P; Puolakka, M; Halonen, L. 2013. Subjective preferences and colour quality metrics of LED light sources. Lighting Research and Technology, volume 45, issue 6, pages 666-688. DOI: 10.1177/1477153512471520
dc.relation.haspart [Publication 3]: Islam, M; Dangol, R; Hyvärinen, M; Bhusal, P; Puolakka, M; Halonen, L. User acceptance studies for LED office lighting: lamp spectrum, spatial brightness and illuminance level. Lighting Research and Technology, first published on December 17, 2013 as DOI: 10.1177/1477153513514425.
dc.relation.haspart [Publication 4]: Dangol, R; Islam, M; Hyvärinen, M; Bhusal, P; Puolakka, M; Halonen, L. User acceptance studies for LED office lighting: Preference, naturalness and colourfulness. Lighting Research and Technology, first published on December 6, 2013 as DOI: 10.1177/1477153513514424.
dc.subject.other Electrical engineering en
dc.title User acceptance studies for LED office lighting: light spectrum and correlated colour temperature en
dc.type G5 Artikkeliväitöskirja fi
dc.contributor.school Sähkötekniikan korkeakoulu fi
dc.contributor.school School of Electrical Engineering en
dc.contributor.department Sähkötekniikan ja automaation laitos fi
dc.contributor.department Department of Electrical Engineering and Automation en
dc.subject.keyword light emitting diode en
dc.subject.keyword spectra en
dc.subject.keyword office lighting en
dc.subject.keyword colour rendering en
dc.subject.keyword correlated colour temperature en
dc.subject.keyword preference en
dc.subject.keyword acceptance en
dc.identifier.urn URN:ISBN:978-952-60-6120-7
dc.type.dcmitype text en
dc.type.ontasot Doctoral dissertation (article-based) en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.contributor.supervisor Halonen, Liisa, Prof., Aalto University, Department of Electrical Engineering and Automation, Finland
dc.opn Khanh, Tran Quoc, Prof., Technical University of Darmstadt, Germany
dc.contributor.lab Lighting Unit en
dc.rev Hanselaer, Peter, Prof., University of Leuven, Belgium
dc.rev Parkkinen, Jussi, Prof., University of Eastern Finland, Finland
dc.date.defence 2015-03-30
local.aalto.digifolder Aalto_64723
local.aalto.formfolder 2015_03_05_klo_10_15
local.aalto.archive yes
local.aalto.digiauth ask


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