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Author (down) Tewolde, F.T.; Lu, N.; Shiina, K.; Maruo, T.; Takagaki, M.; Kozai, T.; Yamori, W.
Title Nighttime Supplemental LED Inter-lighting Improves Growth and Yield of Single-Truss Tomatoes by Enhancing Photosynthesis in Both Winter and Summer Type Journal Article
Year 2016 Publication Frontiers in Plant Science Abbreviated Journal Front Plant Sci
Volume 7 Issue Pages 448
Keywords Plants; LED; fruit quality; lighting period; photosynthesis; plant factory; single-truss tomato; supplemental lighting; yield
Abstract Greenhouses with sophisticated environmental control systems, or so-called plant factories with solar light, enable growers to achieve high yields of produce with desirable qualities. In a greenhouse crop with high planting density, low photosynthetic photon flux density (PPFD) at the lower leaves tends to limit plant growth, especially in the winter when the solar altitude and PPFD at the canopy are low and day length is shorter than in summer. Therefore, providing supplemental lighting to the lower canopy can increase year-round productivity. However, supplemental lighting can be expensive. In some places, the cost of electricity is lower at night, but the effect of using supplemental light at night has not yet been examined. In this study, we examined the effects of supplemental LED inter-lighting (LED inter-lighting hereafter) during the daytime or nighttime on photosynthesis, growth, and yield of single-truss tomato plants both in winter and summer. We used LED inter-lighting modules with combined red and blue light to illuminate lower leaves right after the first anthesis. The PPFD of this light was 165 mumol m(-2) s(-1) measured at 10 cm from the LED module. LED inter-lighting was provided from 4:00 am to 4:00 pm for the daytime treatments and from 10:00 pm to 10:00 am for the nighttime treatments. Plants exposed only to solar light were used as controls. Daytime LED inter-lighting increased the photosynthetic capacity of middle and lower canopy leaves, which significantly increased yield by 27% in winter; however, photosynthetic capacity and yield were not significantly increased during summer. Nighttime LED inter-lighting increased photosynthetic capacity in both winter and summer, and yield increased by 24% in winter and 12% in summer. In addition, nighttime LED inter-lighting in winter significantly increased the total soluble solids and ascorbic acid content of the tomato fruits, by 20 and 25%, respectively. Use of nighttime LED inter-lighting was also more cost-effective than daytime inter-lighting. Thus, nighttime LED inter-lighting can effectively improve tomato plant growth and yield with lower energy cost compared with daytime both in summer and winter.
Address Center for Environment, Health and Field Sciences, Chiba University, Kashiwa, Japan; Department of Biological Sciences, Faculty of Science, The University of Tokyo, Japan
Corporate Author Thesis
Publisher Frontiers Media S.A. Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1664-462X ISBN Medium
Area Expedition Conference
Notes PMID:27092163; PMCID:PMC4823311 Approved no
Call Number IDA @ john @ Serial 1434
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Author (down) 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 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 (down) Tähkämö, L.; Räsänen, R.-S.; Halonen, L.
Title Life cycle cost comparison of high-pressure sodium and light-emitting diode luminaires in street lighting Type Journal Article
Year 2016 Publication The International Journal of Life Cycle Assessment Abbreviated Journal Int J Life Cycle Assess
Volume 21 Issue 2 Pages 137-145
Keywords Economics; Lighting
Abstract Purpose

Cities and municipalities are facing a great challenge in 2015 when the widely used high-pressure mercury lamps are banned from the European Union market. This results to approximately 18 million lamps to be changed to other light source technologies suitable for outdoor lighting. The most probable replacement technologies are high-pressure sodium and light-emitting diode luminaires. The article provides economic information for the cities and municipalities to use when making the decision on the choice of technology.

Methods

A life cycle cost analysis was conducted for the high-pressure sodium and light-emitting diode luminaires including the investment costs, operating costs and residual value over 30-year time frame. The investment costs included the purchase prices of all parts, freight and installation costs. The operating costs accounted for the energy and maintenance costs, and the residual value was calculated using the 25 % estimate of the initial purchase price. The approach of the calculation considered only the luminaires to be installed; the scope of the study excluded the previous installations, which may contain any light source technology or be inexistent. The analysis excluded the poles, wiring and other infrastructure. A sensitivity analysis additionally studied six scenarios, in which relevant calculation parameters were changed.

Results and discussion

The life cycle cost analysis of the two road lighting luminaire technologies showed that the HPS luminaire was normally a more economical solution compared to the light-emitting diode (LED) luminaire. The total life cycle costs of the HPS luminaire were 45 % lower than those of the LED luminaire per kilometre. However, the scenarios in the sensitivity analysis indicated that there were circumstances where the cost-efficiency of the LED luminaire was particularly improved. In order for the LED technology to become fully competitive against the HPS technology, several scenarios have to take place simultaneously. The life cycle costs of the LED luminaire were reduced compared to the HPS luminaire by increased electricity price, exclusion of spot replacements, reduced purchase price and modularity of the LED luminaire.

Conclusions

Despite the greater luminous efficacy, the LED luminaire was found to have greater life cycle costs compared to the HPS luminaire. However, the LED technology is expected to become more economical in the future due to the development in luminous efficacy, improved product quality, reduction in the purchase price and the enhanced competition in the LED segment. Despite the unfavourable cost structure, the LED technology offers other benefits, such as lighting controls and colour characteristics.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0948-3349 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kyba @ Serial 1725
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Author (down) Tapia Ayuga, C.; Sánchez de Miguel, A.; Zamorano Calvo, J.
Title LICA-UCM lamps spectral database Type Report
Year 2015 Publication unpublished Abbreviated Journal
Volume Issue Pages
Keywords Lighting; Instrumentation; technical report; Madrid; Spain; spectroscopy; spectra
Abstract Spectra of the lamps that are used for public lighting and ornamental purposes have been obtained with a portable spectrograph around Madrid city. The database is presented in this report along with a description of the procedures.
Address Grupo UCM de Astrofísica Extragaláctica e Instrumentación Astronómica, Madrid
Corporate Author Thesis
Publisher Place of Publication Madrid Editor
Language English Summary Language Original Title
Series Editor Series Title LICA Reports Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium PDF
Area Expedition Conference
Notes Request to add by CK even though non-peer-reviewed Approved no
Call Number IDA @ john @ Serial 1094
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Author (down) Takemura, Y.; Ito, M.; Shimizu, Y.; Okano, K.; Okano, T.
Title Adaptive light: a lighting control method aligned with dark adaptation of human vision Type Journal Article
Year 2020 Publication Scientific Reports Abbreviated Journal Sci Rep
Volume 10 Issue 1 Pages 11204
Keywords Human Health; Vision; Lighting
Abstract Light exposure before sleep causes a reduction in the quality and duration of sleep. In order to reduce these detrimental effects of light exposure, it is important to dim the light. However, dimming the light often causes inconvenience and can lower the quality of life (QOL). We therefore aimed to develop a lighting control method for use before going to bed, in which the illuminance of lights can be ramped down with less of a subjective feeling of changes in illuminance. We performed seven experiments in a double-blind, randomized crossover design. In each experiment, we compared two lighting conditions. We examined constant illuminance, linear dimming, and three monophasic and three biphasic exponential dimming, to explore the fast and slow increases in visibility that reflect the dark adaptation of cone and rod photoreceptors in the retina, respectively. Finally, we developed a biphasic exponential dimming method termed Adaptive Light 1.0. Adaptive Light 1.0 significantly prevented the misidentification seen in constant light and effectively suppressed perceptions of the illuminance change. This novel lighting method will help to develop new intelligent lighting instruments that reduce the negative effect of light on sleep and also lower energy consumption.
Address The Smart Life Science Institute, ACROSS, Waseda University, Tokyo, Japan. okano@waseda.jp
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
Area Expedition Conference
Notes PMID:32641723; PMCID:PMC7343865 Approved no
Call Number GFZ @ kyba @ Serial 3050
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