scholarly journals On the Technical Performance Characteristics of Horticultural Lamps

2021 ◽  
Vol 3 (4) ◽  
pp. 716-727
Author(s):  
Timothy J. Shelford ◽  
Arend-Jan Both
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Performance Characteristics ◽  
Plant Production ◽  
Sufficient Information ◽  
Light Emitting ◽  
Led Lighting ◽  
Technical Performance ◽  
Lighting Systems ◽  
Greenhouse Growers

Recent advances in light emitting diode (LED) technology have provided exciting opportunities for plant lighting applications, and it is expected that LED lighting will soon overtake the still common use of high-intensity discharge (HID) lighting technology. Because LED lighting offers novel capabilities, extensive research is needed to identify optimal lighting practices for the large number of crops grown by commercial greenhouse growers. Plant scientists and growers facing decisions about plant lighting systems do not always have sufficient information about lamp performance characteristics. In this paper, we reported on various technical performance characteristics for 18 lamp types commonly used for plant production, and compared these characteristics with the characteristics of sunlight. The results showed a substantial range of performance characteristics, highlighting the importance of a careful assessment before selecting a light source for horticultural applications. The data presented in this paper can be used to assess the suitability of a specific light source for a particular horticultural application.

scholarly journals A New Capacitor-Less Buck DC-DC Converter for LED Applications

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Munir Al-Absi ◽  
Zainulabideen Khalifa ◽  
Alaa Hussein
Keyword(s):  
Light Emitting Diode ◽  
Switching Frequency ◽  
Led Driver ◽  
Light Emitting ◽  
Led Lighting ◽  
Full Load ◽  
Lighting Systems

In this paper, a new capacitor-less DC-DC converter is proposed to be used as a light emitting diode (LED) driver. The design is based on the utilization of the internal capacitance of the LED to replace the smoothing capacitor. LED lighting systems usually have many LEDs for better illumination that can reach multiple tens of LEDs. Such configuration can be utilized to enlarge the total internal capacitance and hence minimize the output ripple. Also, the switching frequency is selected such that a minimum ripple appears at the output. The functionality of the proposed design is confirmed experimentally and the efficiency of the driver is 85% at full load.

scholarly journals A method to estimate savings of led lighting instalation in public buildings: The case study of secondary schools in Serbia

2017 ◽  
Vol 21 (6 Part B) ◽  
pp. 2931-2943 ◽  
Author(s):  
Mladen Josijevic ◽  
Dusan Gordic ◽  
Dobrica Milovanovic ◽  
Nebojsa Jurisevic ◽  
Nikola Rakic
Keyword(s):  
Cost Reduction ◽  
Light Emitting Diode ◽  
Electric Energy ◽  
Light Flux ◽  
Electricity Consumption ◽  
Maintenance Cost ◽  
Light Emitting ◽  
Led Lighting ◽  
Lighting Systems

This paper examines the potentials of saving electric energy in school lighting by replacing the existent systems of lighting with more adequate ones which are based on light-emitting diode technology. Our primary goal is to present the methodology used in this analysis since it can be used to determine potential savings in lighting systems of any public building. We have performed the detailed analysis of nine high schools located in Kragujevac, Serbia. The first step was to collect the data about the numbers and types of systems utilized, as well as about the habits of their users. This has revealed the share of electricity consumption for lighting in total electricity consumption. The replacements for each existent light source have been proposed taking into consideration the projected value of light flux depending on the purpose of each room. The calculations of potential savings through the replacement of lighting systems have been conducted taking into consideration not only the savings in electric energy but also the savings made through the maintenance cost reduction. Based on the results, the potential savings range from 53-62% while the payback period for the analysed schools is about four years in average.

scholarly journals The effect of new LED lighting systems on the colour of modern paints

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Valentina Pintus ◽  
Ferenc Szabó ◽  
Renáta Gazdag-Kéri ◽  
Dávid Noel Tóth ◽  
Róbert Nagy ◽  
...  
Keyword(s):  
Near Infrared ◽  
Light Emitting Diode ◽  
Linseed Oil ◽  
Colour Change ◽  
Halogen Lamp ◽  
Light Emitting ◽  
Led Lighting ◽  
Optimization Parameters ◽  
Lighting Systems ◽  
Set Up

AbstractThis research focuses on the investigation of the effect of a new light emitting diode (LED)-lighting system which reproduces indoor museum conditions, on some self-made art paint colours (acrylic-, alkyd-, and linseed oil-based paints) often used in modern-contemporary art. A halogen lamp representing a traditional light source for museum lighting was also considered. Lighting-set-up and lighting optimization parameters were considered while Ultraviolet/Visible/Near Infrared (UV/Vis/NIR) spectrophotometry was used for investigating the colour change of the paint samples. Univariate analyses allowed determining the highest effect of the lighting systems on the linseed oil binder and ultramarine blue PB29 mixture upon ageing, according to the highest total colour change ΔE*ab. In a more specific and detailed way, variance analyses not only demonstrated the strong correlation between the type of binder and pigment used for the paint samples with the colour variation, but also showed that the short-wavelength blue LEDs influenced the change along the yellow–blue b* axis of the yellow and blue samples, whereas the halogen lamp mostly had an impact towards the red–green a* axis of mostly the green specimens.

Using Brainwaves and Eye Tracking to Determine Attention Levels for Auto-Lighting Systems

2015 ◽  
Vol 19 (5) ◽  
pp. 611-618
Author(s):  
Junzo Watada ◽  
◽  
Yung-Chin Hsiao ◽  
Hanayuki Kitagawa
Keyword(s):  
Eye Tracking ◽  
Light Emitting Diode ◽  
Visual Awareness ◽  
Light Emitting ◽  
Led Lighting ◽  
Lighting Technology ◽  
Car Accidents ◽  
Lighting Systems ◽  
The Relationship ◽  
Daytime Running Light

To prevent car accidents, it should be possible for pedestrians and other drivers to detect oncoming vehicles. Many car accidents are caused because persons are not aware of approaching traffic, and this applies especially to visual awareness. The daytime running light (DRL) and the third braking light (TBL) were developed to significantly increase the visibility of vehicles, and their effectiveness has been verified through numerous studies. Usage of light-emitting diode (LED) lighting technology has also become popular in auto-lighting systems because of its advantages of energy efficiency, long life, and stylish appearance. However, LED lighting technology is very different from conventional incandescent or high-intensity discharge (HID) lighting technology. In this paper, we determine the effectiveness of LEDs as DRLs and TBLs. We measure human attention levels by observing brainwaves and performing eye-tracking experiments that shows the relationship between the theory of attention, brainwaves, and eye tracking. The results obtained show that it is feasible to evaluate automotive exterior lighting using the attention levels of subjects.

Rational Basis for Light Emitting Diode Street Lighting Retrofit Luminaire Selection

2021 ◽  
pp. 036119812110038
Author(s):  
Jennifer A. Brons ◽  
John D. Bullough ◽  
Daniel C. Frering
Keyword(s):  
Light Emitting Diode ◽  
Light Output ◽  
Limited Range ◽  
Street Lighting ◽  
Light Emitting ◽  
Led Lighting ◽  
The Road ◽  
Lighting Systems ◽  
On The Road ◽  
Lighting Retrofit

Many municipalities are beginning to undertake efforts to retrofit their existing high pressure sodium (HPS) street lighting with LED (light emitting diode) luminaires. Unlike HPS lighting systems, which are available in a limited range of standard wattages and configurations, LED street lighting systems vary widely in wattage and physical configuration. Moreover, the technological performance of LED lighting continues to improve, whereas HPS is a mature technology with substantial improvements unlikely in the future. To develop a sound basis for selecting LED lighting systems for retrofit street lighting, photometric simulation calculations under a range of pole spacing, road width and luminaire wattage were performed. The results indicated that LED luminaires can have substantially lower wattage than HPS luminaires to produce the same light levels on the road. Further, LED luminaires tend to direct more of their output onto the road compared with HPS luminaires. As a result, LED luminaires can be used that produce substantially fewer lumens overall than HPS systems. Because the white light from LED sources makes illuminated street scenes appear brighter than the yellowish light from HPS lamps, even further reductions in light output can be accomplished with LED street lighting systems to match the same visual effect under HPS.

Organic Light Emitting Diodes - Innovative Light Sources

2019 ◽  
pp. 101-107
Author(s):  
Sergei A. Stakharny
Keyword(s):  
Light Source ◽  
Organic Light Emitting Diodes ◽  
Organic Leds ◽  
Light Sources ◽  
High Quality ◽  
Light Emitting ◽  
Organic Light ◽  
Lighting Systems ◽  
Physical Principles ◽  
Prospects Of Application

This article is a review of the new light source – organic LEDs having prospects of application in general and special lighting systems. The article describes physical principles of operation of organic LEDs, their advantages and principal differences from conventional non-organic LEDs and other light sources. Also the article devoted to contemporary achievements and prospects of development of this field in the spheres of both general and museum lighting as well as other spheres where properties of organic LEDs as high-quality light sources may be extremely useful.

scholarly journals A Supervisory Control Strategy for Improving Energy Efficiency of Artificial Lighting Systems in Greenhouses

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 202
Author(s):  
Gianluca Serale ◽  
Luca Gnoli ◽  
Emanuele Giraudo ◽  
Enrico Fabrizio
Keyword(s):  
Control Strategy ◽  
Light Emitting Diode ◽  
Cost Savings ◽  
Energy Performance ◽  
Lighting System ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Lighting Control ◽  
Lighting Systems ◽  
Power Densities

Artificial lighting systems are used in commercial greenhouses to ensure year-round yields. Current Light Emitting Diode (LED) technologies improved the system efficiency. Nevertheless, having artificial lighting systems extended for hectares with power densities over 50W/m2 causes energy and power demand of greenhouses to be really significant. The present paper introduces an innovative supervisory and predictive control strategy to optimize the energy performance of the artificial lights of greenhouses. The controller has been implemented in a multi-span plastic greenhouse located in North Italy. The proposed control strategy has been tested on a greenhouse of 1 hectare with a lighting system with a nominal power density of 50 Wm−2 requiring an overall power supply of 1 MW for a period of 80 days. The results have been compared with the data coming from another greenhouse of 1 hectare in the same conditions implementing a state-of-the-art strategy for artificial lighting control. Results outlines that potential 19.4% cost savings are achievable. Moreover, the algorithm can be used to transform the greenhouse in a viable source of energy flexibility for grid reliability.

scholarly journals Light Emitting Diodes (LEDs) as Agricultural Lighting: Impact and Its Potential on Improving Physiology, Flowering, and Secondary Metabolites of Crops

2021 ◽  
Vol 13 (4) ◽  
pp. 1985
Author(s):  
Musa Al Murad ◽  
Kaukab Razi ◽  
Byoung Ryong Jeong ◽  
Prakash Muthu Arjuna Samy ◽  
Sowbiya Muneer
Keyword(s):  
Crop Production ◽  
Morphological Changes ◽  
Light Emitting Diode ◽  
Crop Productivity ◽  
Photon Flux ◽  
Flower Initiation ◽  
Nutrient Metabolism ◽  
Light Emitting ◽  
Cultivation Systems ◽  
Lighting Systems

A reduction in crop productivity in cultivable land and challenging environmental factors have directed advancement in indoor cultivation systems, such that the yield parameters are higher in outdoor cultivation systems. In wake of this situation, light emitting diode (LED) lighting has proved to be promising in the field of agricultural lighting. Properties such as energy efficiency, long lifetime, photon flux efficacy and flexibility in application make LEDs better suited for future agricultural lighting systems over traditional lighting systems. Different LED spectrums have varied effects on the morphogenesis and photosynthetic responses in plants. LEDs have a profound effect on plant growth and development and also control key physiological processes such as phototropism, the immigration of chloroplasts, day/night period control and the opening/closing of stomata. Moreover, the synthesis of bioactive compounds and antioxidants on exposure to LED spectrum also provides information on the possible regulation of antioxidative defense genes to protect the cells from oxidative damage. Similarly, LEDs are also seen to escalate the nutrient metabolism in plants and flower initiation, thus improving the quality of the crops as well. However, the complete management of the irradiance and wavelength is the key to maximize the economic efficacy of crop production, quality, and the nutrition potential of plants grown in controlled environments. This review aims to summarize the various advancements made in the area of LED technology in agriculture, focusing on key processes such as morphological changes, photosynthetic activity, nutrient metabolism, antioxidant capacity and flowering in plants. Emphasis is also made on the variation in activities of different LED spectra between different plant species. In addition, research gaps and future perspectives are also discussed of this emerging multidisciplinary field of research and its development.

Comparison of the effects of operating microscopes with light emitting diode and halogen light source on the eye: a rabbit study

2021 ◽  
pp. 1-7
Author(s):  
Bahri Aydın ◽  
Armagan Ozgur ◽  
Huseyin Baran Ozdemir ◽  
Pınar Uyar Gocun ◽  
Mehmet Arda Inan ◽  
...  
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Halogen Light ◽  
Halogen Light Source

scholarly journals Increased Plant Quality, Greenhouse Productivity and Energy Efficiency with Broad-Spectrum LED Systems: A Case Study for Thyme (Thymus vulgaris L.)

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 960
Author(s):  
Jenny Manuela Tabbert ◽  
Hartwig Schulz ◽  
Andrea Krähmer
Keyword(s):  
Broad Spectrum ◽  
Energy Savings ◽  
Light Emitting Diode ◽  
Thymus Vulgaris ◽  
Light Spectrum ◽  
Light Emitting ◽  
Biomass Yields ◽  
Lighting Systems

A light-emitting diode (LED) system covering plant-receptive wavebands from ultraviolet to far-red radiation (360 to 760 nm, “white” light spectrum) was investigated for greenhouse productions of Thymus vulgaris L. Biomass yields and amounts of terpenoids were examined, and the lights’ productivity and electrical efficiency were determined. All results were compared to two conventionally used light fixture types (high-pressure sodium lamps (HPS) and fluorescent lights (FL)) under naturally low irradiation conditions during fall and winter in Berlin, Germany. Under LED, development of Thymus vulgaris L. was highly accelerated resulting in distinct fresh yield increases per square meter by 43% and 82.4% compared to HPS and FL, respectively. Dry yields per square meter also increased by 43.1% and 88.6% under LED compared to the HPS and FL lighting systems. While composition of terpenoids remained unaffected, their quantity per gram of leaf dry matter significantly increased under LED and HPS as compared to FL. Further, the power consumption calculations revealed energy savings of 31.3% and 20.1% for LED and FL, respectively, compared to HPS. In conclusion, the implementation of a broad-spectrum LED system has tremendous potential for increasing quantity and quality of Thymus vulgaris L. during naturally insufficient light conditions while significantly reducing energy consumption.

Sign in / Sign up

Export Citation Format

Share Document