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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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This report is an analysis of niche markets and applications for light-emitting diodes (LEDs), undertaken on behalf of the U.S. Department of Energy.
Through its grid-interactive efficient building (GEB) research, the DOE Building Technologies Office seeks to build on existing energy-efficiency efforts and develop technological capabilities to optimize the interplay between building loads and the electric grid. This report analyzes connected lighting systems and consumer electronics/IT equipment technologies. All lighting technologies are assumed to be lighting-emitting diode (LED) or organic LED (OLED) technologies. These technologies are analyzed in two separate sections and the evaluations are not meant to be comparable to each other or other building technologies.
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Highlights: • A new combination of Pr{sub 6}O{sub 11}/g-C{sub 3}N{sub 4} photocatalyst is synthesized by simple solvent free solid state method. • The photocatalytic activity of Pr{sub 6}O{sub 11}/g-C{sub 3}N{sub 4} is investigated by degradation of AV7 dye under visible light. • Improved performance is attributed to enhanced visible light absorption and efficient charge separation as evidenced by photoelectrochemical study. • Pr{sub 6}O{sub 11}/g-C{sub 3}N{sub 4} also exhibit super capacitance behavior. - Abstract: A new Pr{sub 6}O{sub 11}/g-C{sub 3}N{sub 4} heterostructure material has been prepared by single step solvent free solid state method for photocatalytic environmental cleaning application using visible light. The Pr{sub 6}O{sub 11}/g-C{sub 3}N{sub 4} heterostructure exhibits enhanced visible light absorption, resulting in improved photoelectrochemical properties and photocatalytic performance. The optimized composition of Pr{sub 6}O{sub 11}/g-C{sub 3}N{sub 4} composite shows improved degradation kinetics and completely degrades AV7 dye within 20 min of visible light irradiation. Photoluminescence and electrochemical studies suggest better separation of photogenerated charge carriers in the composite compared to single phase materials. This is further substantiated by the improved photocurrent response of the composite. The notable increase of photocatalytic activity of Pr{sub 6}O{sub 11}/g-C{sub 3}N{sub 4} heterostructure is ascribed to the improved visible light absorption, reduced band gap and better separation of photogenerated electrons and holes. To the best of our knowledge, this new heterostructure photocatalyst is found to be more efficient for the degradation of AV7 dye compared to the systems reported so far.
Fact sheet that provides an overview of DOE's L Prize competition, which challenges industry to develop high-quality, high-efficiency SSL products to replace 60W incandescent and PAR38 halogen light bulbs, and highlights the competition's first 60W winner from Philips Lighting North America.
Substitution of a varying number of 9H-carbazole donors onto 2-(pentafluorophenyl)-5-phenyl-1,3,4-oxadiazole yields a series of donor–acceptor compounds with similar electrochemical band gaps, but dissimilar optical properties. Each substitution of a carbazole onto the 2- and 4-positions results in a 150–200 meV stabilization of the first singlet excited state, evident in the fluorescent emission. Here, the first triplet excited state is less sensitive to these substitutions, leading to a reduced energy separation between the singlet and triplet states, ΔE ST , with increasing carbazole content. OLED devices made using the donor–acceptor compounds exhibiting the lowest ΔE ST were fabricated and exhibit sky blue emission with an external quantum efficiency of up to 24.4% at a luminance of 10 cd m –2 , and 9.2% at 1000 cd m –2 .
The Jordan Schnitzer Museum of Art in Eugene, Oregon, houses a remarkable permanent collection of Asian art and antiquities, modern art, and sculpture, and also hosts traveling exhibitions. In the winter and spring of 2011, a series of digital photographs by artist Chris Jordan, titled "Running the Numbers," was exhibited in the Coeta and Donald Barker Special Exhibitions Gallery. These works graphically illustrate waste (energy, money, health, consumer objects, etc.) in contemporary culture. The Bonneville Power Administration and the Eugene Water and Electricity Board provided a set of Cree 12W light-emitting diode (LED) PAR38 replacement lamps (Cree LRP38) for the museum to test for accent lighting in lieu of their standard Sylvania 90W PAR38 130V Narrow Flood lamps (which draw 78.9W at 120V). At the same time, the museum tested LED replacement lamps from three other manufacturers, and chose the Cree lamp as the most versatile and most appropriate color product for this exhibit. The lamps were installed for the opening of the show in January 2011. This report describes the process for the demonstration, the energy and economic results, and results of a survey of the museum staff and gallery visitors on four similar clusters of art lighted separately by four PAR38 lamps.
Synopsis: Light loss factors are used to help lighting systems meet quantitative design criteria throughout the life of the installation, but they also influence energy use. As the light sources currently being specified continue to evolve, it is necessary to reevaluate the methods used in calculating light loss factors, as well as carefully consider the consequences of different product performance attributes. Because of the unique operating characteristics of LEDs and lack of a comprehensive lifetime rating—as well as the problematic relationship between lifetime and lumen maintenance—determining an appropriate lamp lumen depreciation (LLD) factor for LED products is difficult. As a result, a unique solution has been advocated: when quantity of light is an important design consideration, the IES recommends using an LLD of not greater than 0.70. This method deviates from the typical practice for conventional sources of using the ratio of mean to initial lumen output, and can misrepresent actual performance, increase energy use, and inhibit comparisons between products. This paper discusses the complications related to LLD and LEDs, compares the performance of conventional and LED products, and examines alternatives to a maximum LLD of 0.70 for LEDs.
The Pacific Northwest National Laboratory, operated by Battelle for the U.S. Department of Energy, worked with Intertek to develop a procedure for stress testing medium screw-base light sources. This procedure, composed of alternating stress cycles and performance evaluation, was used to qualitatively compare and contrast the durability and reliability of the Philips 60W replacement lamp L Prize entry with market-proven compact fluorescent lamps (CFLs) with comparable light output and functionality. The stress cycles applied simultaneous combinations of electrical, thermal, vibration, and humidity stresses of increasing magnitude. Performance evaluations measured relative illuminance, x chromaticity and y chromaticity shifts after each stress cycle. The Philips L Prize entry lamps appear to be appreciably more durable than the incumbent energy-efficient technology, as represented by the evaluated CFLs, and with respect to the applied stresses. Through the course of testing, all 15 CFL samples permanently ceased to function as a result of the applied stresses, while only 1 Philips L Prize entry lamp exhibited a failure, the nature of which was minor, non-destructive, and a consequence of a known (and resolved) subcontractor issue. Given that current CFL technology appears to be moderately mature and no Philips L Prize entry failures could be produced within the stress envelope causing 100 percent failure of the benchmark CFLs, it seems that, in this particular implementation, light-emitting diode (LED) technology would be much more durable in the field than current CFL technology. However, the Philips L Prize entry lamps used for testing were carefully designed and built for the competition, while the benchmark CFLs were mass produced for retail sale—a distinction that should be taken into consideration. Further reliability testing on final production samples would be necessary to judge the extent to which the results of this analysis apply to production versions of the Philips L Prize entry.
This GATEWAY report discusses the problems of pedestrian lighting that occur with all technologies with a focus on the unique optical options and opportunities offered by LEDs through the findings from two pedestrian-focused projects, one at Stanford University in California, and one at the Chautauqua Institution in upstate New York. Incorporating user feedback this report reviews the tradeoffs that must be weighed among visual comfort, color, visibility, efficacy and other factors to stimulate discussion among specifiers, users, energy specialists, and in industry in hopes that new approaches, metrics, and standards can be developed to support pedestrian-focused communities, while reducing energy use.
Who's to say that a little light can t go a long way? Tiny light-emitting diode (LED) chips used to grow plants in space are lighting the way for cancer treatment, wound healing, and chronic pain alleviation on Earth. In 1993, Quantum Devices, Inc. (QDI), of Barneveld, Wisconsin, began developing the HEALS (High Emissivity Aluminiferous Light-emitting Substrate) technology to provide high-intensity, solid-state LED lighting systems for NASA Space Shuttle plant growth experiments. The company evolved out of cooperative efforts with the Wisconsin Center for Space Automation and Robotics (WCSAR) at the University of Wisconsin-Madison a NASA center for the Commercial Development of Space. Ronald W. Ignatius, QDI s president and chairman, represented one of WCSAR s industrial partners at the time. WCSAR was conducting research on light sources for promoting food growth within closed environments where humans would be present for a long duration, such as the Space Shuttle and the International Space Station. With the support of WCSAR, Ignatius experimented with LEDs, which provide high-energy efficiency and virtually no heat, despite releasing waves of light 10 times brighter than the Sun. Ignatius admits that some scientists involved in the project were skeptical at first, thinking that the idea of using LEDs to promote plant growth was far-fetched. The experiments, however, demonstrated that red LED wavelengths could boost the energy metabolism of cells to advance plant growth and photosynthesis. This finding prompted Ignatius to develop a line of LED products that emit the exact wavelength of light that plants use in photosynthesis. Our company gives credit to Dr. Ray Bula, the director of WCSAR, for having the foresight to go against the prevailing dogma of the time and design the first plant experiment using monochromatic light to grow lettuce plants, Ignatius proclaims. In 1989, Ignatius formed QDI to bring the salt grain-sized LEDs to market, and in October 1995, the light sources made their Space Shuttle flight debut on the second U.S. Microgravity Laboratory Spacelab mission (STS-73, Columbia)
Brief summary of 2015 SSL Adoption of Light-Emitting Diodes in Common Lighting Applications report.
Case study describes how the Northwest/Arctic Region branch of the General Services Administration (GSA) improved safety and energy efficiency in its Fairbanks Federal Building parking garage used by federal employees, U.S. Marshals, and the District Court. A 74% savings was realized by replacing 220 high-pressure sodium fixtures with 220 light-emitting diode fixtures.
This article will be published in the November issue of the International Facility Management Association's sustainability newsletter. The article both informs facility managers of the Interior Lighting Campaign, and invites them to participate. Highlights include the new types of lamps recently included along with program details.
The rapid advancement in the field of science has led to the development of many technologies, gadgets and equipment which in turn has hold pressure on Wi-Fi, modems, board band connections etc., to lessen this stress new revolution in this field has rooted on termed “LI-FI”. Li-Fi stands for light fidelity i.e. light is used for the transmission of data. The concept of Li-Fi is taking the fiber out of fiber optics sending information through an LED that varies in intensity faster than human eye can follow. Li-Fi offers an entirely new paradigm in wireless technology in term of communication, speed, flexibility, usability etc. The idea of data through illumination is similar to radio waves communication difference lies in the use of LED in LI-Fi, which made it superior than Wi-Fi. Hence Li-Fi is linked to the visible light communication network provision transmission which is looked upon as an advancement. Thus a new class of light with high intensity light source of solid state design bringing clean lighting solution to general and specialty lighting. With energy efficiency, long useful lifetime, full spectrum and dimming. Li-Fi is just not only confined to light and LED indeed it is a platform with versatile advantages and facilities. This paper gives a brief idea about the introduction of Li-Fi, its working, advantages, limitations etc.
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