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Author Femia, N.; Fortunato, M.; Vitelli, M.
Title Light-to-Light: PV-Fed LED Lighting Systems Type Journal Article
Year 2013 Publication IEEE Transactions on Power Electronics Abbreviated Journal IEEE Trans. Power Electron.
Volume 28 Issue 8 Pages 4063-4073
Keywords light-to-light systems; outdoor lighting; lighting technology; LED; LED lighting; photovoltaics; PV
Abstract This paper discusses the principle of operation, dynamic modeling, and control design for light-to-light (LtL) systems, whose aim is to directly convert the sun irradiation into artificial light. The system discussed in this paper is composed by a photovoltaic (PV) panel, an LED array, a dc-dc converter dedicated to the maximum power point tracking of the PV panel and a dc-dc converter dedicated to drive the LEDs array. A system controller is also included, whose goal is to ensure the matching between the maximum available PV power and the LED power by means of a low-frequency LEDs dimming. An experimental design example is discussed to illustrate the functionalities of the LtL system.
Address Dipt. di Ing. Elettron. e Ing. Inf., Univ. of Salerno, Salerno, Italy
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ISSN 0885-8993 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 331
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Author Tähkämö, L.; Ylinen, A.; Puolakka, M.; Halonen, L.
Title Life cycle cost analysis of three renewed street lighting installations in Finland Type Journal Article
Year 2012 Publication The International Journal of Life Cycle Assessment Abbreviated Journal Int J Life Cycle Assess
Volume 17 Issue 2 Pages 154-164
Keywords LED; LED lighting; Life cycle costs; Light-emitting diode; Payback time; Road lighting; Street lighting
Abstract Purpose

Outdoor lighting is facing major changes due to the EU legislation on ecodesign of energy-related products, such as the ban of high-pressure mercury (HPM) lamps widely used in outdoor lighting. This article presents life cycle costs (LCC) of three examples of replacing HPM lamps in street lighting in Finland. The purpose of the article is to assess how the development of light-emitting diode (LED) technology affects LCCs and how the division of LCCs differentiates in the cases.

Methods

Two of the cases change from HPM lamps to high-pressure sodium (HPS) lamps. In the third one, HPM lamps are replaced by LED luminaires. LED technology predictions of price and luminous efficacy are included in different scenarios. The calculations consider investment and operating costs and residual value.

Results and discussion

Each replacement reduces the energy costs approximately by half compared to the original HPM lamp luminaires. Energy costs dominate the LCCs of the HPS lamp installations while investment cost is the dominating one in LED luminaire case. The changes from HPM to HPS technology have payback times lower than 9 years, while changing to LED luminaires is not economic. However, the electricity price is low in this case. The payback times of LED installations can be as low as 6 years if the luminaires are installed in 2015 and an average electricity price is used.

Conclusions

The LCCs of real-life case studies cannot be directly compared, since their luminous properties vary. There is a need for a method for including luminous properties in LCC calculations.
Address Lighting Unit, School of Electrical Engineering, Aalto University, P.O. Box 13340, 00076, Aalto, Finland
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title (up) Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0948-3349 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 332
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Author Rabaza, O.; Galadi-Enriquez, D.; Estrella, A.E.; Dols, F.A.
Title All-sky brightness monitoring of light pollution with astronomical methods Type Journal Article
Year 2010 Publication Journal of Environmental Management Abbreviated Journal J Environ Manage
Volume 91 Issue 6 Pages 1278-1287
Keywords *Astronomy; Calibration; *Environmental Pollutants; *Light
Abstract This paper describes a mobile prototype and a protocol to measure light pollution based on astronomical methods. The prototype takes three all-sky images using BVR filters of the Johnson-Cousins astronomical photometric system. The stars are then identified in the images of the Hipparcos and General Catalogue of Photometric Data II astronomical catalogues, and are used as calibration sources. This method permits the measurement of night-sky brightness and facilitates an estimate of which fraction is due to the light up-scattered in the atmosphere by a wide variety of man-made sources. This is achieved by our software, which compares the sky background flux to that of many stars of known brightness. The reduced weight and dimensions of the prototype allow the user to make measurements from virtually any location. This prototype is capable of measuring the sky distribution of light pollution, and also provides an accurate estimate of the background flux at each photometric band.
Address Department of Civil Engineering, University of Granada, Severo Ochoa Str. s/n, 18071 Granada, Spain. ovidio@ugr.es
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title (up) Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0301-4797 ISBN Medium
Area Expedition Conference
Notes PMID:20199844 Approved no
Call Number IDA @ john @ Serial 192
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Author Duriscoe, D.M.; Luginbuhl, C.B.; Moore, C.W.
Title Measuring Night-Sky Brightness with a Wide-Field CCD Camera Type Journal Article
Year 2007 Publication Publications of the Astronomical Society of the Pacific Abbreviated Journal Publ Astron Soc Pac
Volume 119 Issue 852 Pages 192-213
Keywords light pollution; light at night; skyglow; monitoring; measurement; CCD
Abstract We describe a system for rapidly measuring the brightness of the night sky using a mosaic of CCD images obtained with a low-cost automated system. The portable system produces millions of independent photometric measurements covering the entire sky, enabling the detailed characterization of natural sky conditions and light domes produced by cities. The measurements are calibrated using images of standard stars contained within the raw data, producing results closely tracking the Johnson V astronomical standard. The National Park Service has collected hundreds of data sets at numerous parks since 2001 and is using these data for the protection and monitoring of the night-sky visual resource. This system also allows comprehensive characterization of sky conditions at astronomical observatories. We explore photometric issues raised by the broadband measurement of the complex and variable night-sky spectrum, and potential indices of night-sky quality.
Address
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ISSN 0004-6280 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 193
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Author Schnitt, S.; Ruhtz, T.; Fischer, J.; Hölker, F.; Kyba, C.C.M.
Title Temperature stability of the sky quality meter Type Journal Article
Year 2013 Publication Sensors (Basel, Switzerland) Abbreviated Journal Sensors (Basel)
Volume 13 Issue 9 Pages 12166-12174
Keywords *Artifacts; Atmosphere/*analysis; Environmental Monitoring/*instrumentation; Equipment Design; Equipment Failure Analysis; Photometry/*instrumentation; Reproducibility of Results; Sensitivity and Specificity; Temperature; *Transducers; Sky Quality Meter; SQM
Abstract The stability of radiance measurements taken by the Sky Quality Meter (SQM)was tested under rapidly changing temperature conditions during exposure to a stable light field in the laboratory. The reported radiance was found to be negatively correlated with temperature, but remained within 7% of the initial reported radiance over a temperature range of -15 degrees C to 35 degrees C, and during temperature changes of -33 degrees C/h and +70 degrees C/h.This is smaller than the manufacturer's quoted unit-to-unit systematic uncertainty of 10%,indicating that the temperature compensation of the SQM is adequate under expected outdoor operating conditions.
Address Institute for Space Sciences, Freie Universitat Berlin, Carl-Heinrich-Becker-Weg 6-10, Berlin 12165, Germany. christopher.kyba@wew.fu-berlin.de
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title (up) Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1424-8220 ISBN Medium
Area Expedition Conference
Notes PMID:24030682; PMCID:PMC3821345 Approved no
Call Number IDA @ john @ Serial 194
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