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Author Ho, C.Y.; Lin, H.T.; Huang, K.Y.
Title A Study on Energy Saving and Light Pollution of LED Advertising Signs Type Journal Article
Year 2011 Publication Applied Mechanics and Materials Abbreviated Journal Amm
Volume 121-126 Issue Pages 2979-2984
Keywords Advertising Sign; LED; Light Trespass; Luminance Limit; Saving Energy; Vertical Illuminance; *Lighting
Abstract Lighting advertising signs not only play an important role in outdoor lighting environment in Taiwan, but also become the main factor of energy consumption in urban areas at night. Light-emitting diode (LED) has been gradually used in advertising signs due to its advantages. However, in order to be conspicuous and legible in the daytime, signs that are excessively bright may result in considerable light pollution and energy waste at nighttime. Therefore, this research aims to measure the luminance of LED signs and traditional internally lighted signs, and analyze the light trespass from each signage. Based on the research results, the energy consumption from a LED full color screen is 12 times more than a traditional internally lighted sign per day. Statistically, all kinds of LED signs are much higher than traditional internally lighted signs in the percentage of excessive brightness and average luminance value. As for the light trespass, since the vertical illuminance on facade facing the signs increases with the increase of the sign area or the decrease of the distance between the sign and the facade, the vertical illuminance on facade facing the signs would exceed the limit of CIE even if the luminance of the signs achieves the standard of CIE in terms of the general conditions in Taiwan. This happens to LED full color screens in particular and thus results in considerable obtrusive light. To sum up, in order to reduce unnecessary energy consumption and improve the nighttime lighting quality for outdoor environment, this research recommends the luminance limitation for light dimming of LED advertising signs should refer to the zoning, time period, and sign area.
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Series Volume Series Issue Edition
ISSN 1662-7482 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 126
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Author Kyba, C.C.M.; Hänel, A.; Hölker, F.
Title Redefining efficiency for outdoor lighting Type Journal Article
Year 2014 Publication Energy & Environmental Science Abbreviated Journal Energy Environ. Sci.
Volume 7 Issue 6 Pages 1806
Keywords *Lighting; outdoor lighting; luminous efficiency; lighting standards; public policy; illuminance; street lighting
Abstract Improvements in the luminous efficiency of outdoor lamps might not result in energy savings or reductions in greenhouse gas emissions. The reason for this is a rebound effect: when light becomes cheaper, many users will increase illumination, and some previously unlit areas may become lit. We present three policy recommendations that work together to guarantee major energy reductions in street lighting systems. First, taking advantage of new technologies to use light only when and where it is needed. Second, defining maximum permitted illuminances for roadway lighting. Third, defining street lighting system efficiency in terms of kilowatt hours per kilometer per year. Adoption of these policies would not only save energy, but would greatly reduce the amount of light pollution produced by cities. The goal of lighting policy should be to provide the light needed for any given task while minimizing both the energy use and negative environmental side effects of the light.
Address Leibniz Institute of Freshwater Ecology and Inland Fisheries, Germany
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ISSN 1754-5692 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 244
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Author Narendran, N.; Freyssinier, J.; Zhu, Y.
Title Energy and user acceptability benefits of improved illuminance uniformity in parking lot illumination Type Journal Article
Year 2015 Publication Lighting Research and Technology Abbreviated Journal Lighting Res. & Tech.
Volume 48 Issue 7 Pages 789-809
Keywords Lighting; parking lots; uniformity; light distribution; illuminance; LED
Abstract This study set out to understand the benefits of improved illuminance uniformity in parking lots in terms of user perception and acceptability, as well as energy use, and to demonstrate that light-emitting diodes (LEDs) can achieve uniform distributions more efficiently than traditional light sources. The results from a field evaluation showed that more uniform illuminance distributions are favourably perceived by people in terms of goodness of illumination, ability to see around and at a distance, and perception of safety -- all of this at a much lower average horizontal illuminance. Thus, improving uniformity alone can translate into lower energy use and potential for less glare and light pollution. Optical modelling showed that LEDs have a much greater potential to efficiently produce uniform illuminance distributions than larger light sources such as high pressure sodium or metal halide.
Address Lighting Research Center, 21, Union Street, Troy, NY 12180, USA; narenn2@rpi.edu
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Publisher SAGE Place of Publication Editor
Language English Summary Language English Original Title
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Notes Approved no
Call Number IDA @ john @ Serial 1184
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Author Prayag, A.S.; Najjar, R.P.; Gronfier, C.
Title Melatonin suppression is exquisitely sensitive to light and primarily driven by melanopsin in humans Type Journal Article
Year 2019 Publication Journal of Pineal Research Abbreviated Journal J Pineal Res
Volume 66 Issue 4 Pages e12562
Keywords Human Health; melatonin suppression; melanopic illuminance
Abstract INTRODUCTION: Light elicits a range of non-visual responses in humans. Driven predominantly by intrinsically photosensitive retinal ganglion cells (ipRGCs), but also by rods and/or cones, these responses include melatonin suppression. A sigmoidal relationship has been established between melatonin suppression and light intensity, however photoreceptoral involvement remains unclear. METHODS AND RESULTS: In this study, we first modelled the relationships between alpha-opic illuminances and melatonin suppression using an extensive dataset by Brainard and colleagues. Our results show that 1) melatonin suppression is better predicted by melanopic illuminance compared to other alpha-opic illuminances, 2) melatonin suppression is predicted to occur at levels as low as ~1.5 melanopic lux (melanopsin-weighted irradiance 0.2 muW/cm(2)), 3) saturation occurs at 305 melanopic lux (melanopsin-weighted irradiance 36.6 muW/cm(2)). We then tested this melanopsin-weighted illuminance response model derived from Brainard and colleagues' data and show that it predicts equally well melatonin suppression data from our laboratory, although obtained using different intensities and exposure duration. DISCUSSION: Together, our findings suggest that melatonin suppression by monochromatic lights is predominantly driven by melanopsin, and that it can be initiated at extremely low melanopic lux levels in experimental conditions. This emphasizes the concern of the non-visual impacts of low light intensities in lighting design and light-emitting devices. This article is protected by copyright. All rights reserved.
Address Lyon Neuroscience Research Center, Integrative Physiology of the Brain Arousal Systems, Waking team, Inserm UMRS 1028, CNRS UMR 5292, Universite Claude Bernard Lyon 1, Universite de Lyon, F-69000, Lyon, France
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Language English Summary Language Original Title
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ISSN 0742-3098 ISBN Medium
Area Expedition Conference
Notes PMID:30697806 Approved no
Call Number GFZ @ kyba @ Serial 2186
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Author Rea, M.S.; Bullough, J.D.; Brons, M.S.
Title Spectral considerations for outdoor lighting: Designing for perceived scene brightness Type Journal Article
Year 2014 Publication Lighting Research and Technology Abbreviated Journal Lighting Res. & Tech.
Volume 47 Issue 8 Pages 909-919
Keywords Public Safety; outdoor lighting; photopic; photopic illuminance; human vision; metrics; task lighting; parking lots
Abstract Photopic illuminance is the photometric metric used today for specifying parking lot lighting levels. The photopic luminous efficiency function does not represent the spectral sensitivity of the perceived scene brightness of parking lots. Sources with a greater proportion of short-wavelength radiation will be seen as brighter for the same photopic illuminance. Moreover, the psychological benefit of providing people with a sense of safety and security in a parking lot is better correlated with the perceived brightness of the parking lot than with its photopic illuminance. Because photopic illuminance is not predictive of the psychological benefit expected from the parking lot lighting system, electric energy will be unnecessarily wasted if specifications are based upon this metric. Specifying parking lot lighting with a benefit metric based upon perceived scene brightness could reduce electric power requirements as well as the amount of radiant energy reflecting from the pavement and escaping into the night sky. A method of equating brightness for different spectral power distributions is provided.
Address Lighting Research Center, Rensselaer Polytechnic Institute, Troy, New York, USA
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Notes Approved no
Call Number IDA @ john @ Serial 1074
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