Take a look at these wind-powered robotic "Art Pieces"! Like a modern-day Leonardo da Vinci genius, conducting an experiment at the beach.

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Here is part 2 and concluding video on the contest between 3 great cars; the Aston Martin V8 Vantage, BMW M6, and Porsche 911 Carrera S.

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Recessed downlights are the most commonly installed type of lighting fixture in residential new construction. New developments in LED technology and luminaire design may enable significant energy savings in this application. This fact sheet compares the energy and lighting performance of downlights using different light sources.

Although originally intended for directional lighting, recessed downlights are now used widely for general ambient lighting in kitchens, hallways, bathrooms, and other areas of the home. Other types of downlights using spot lamps, reflectors, and lenses are also used for art, accent, display, and wall lighting. In some applications, like media rooms and dining areas, downlights are operated on dimming circuits. The most common light source used in residential downlights is a 65-watt incandescent reflector-style lamp with a standard Edison base. Other commonly used options include A-type incandescent lamps, and PL-type, spiral, or reflector CFLs.

Recently, LED downlights have come on the market.

Below are examples of performance data for residential recessed downlight using several different light sources, including two LED products. These data should not be used to generalize the performance of fixture types, but are provided as examples. 

Examples of Recessed Downlight Performance Using Different Light Sources

Source: EERE

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How do the lifetime projections for today’s white LEDs compare to traditional light sources?

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Electrical and thermal design of the LED system or fixture determine how long the LED light will last and how much light they will provide. Driving the LED at higher than rated current will increase relative light output but decrease useful life. Operating the LED at higher than design temperature will also decrease useful life significantly.
Most manufacturers of high-power white LED lights estimate a lifetime of around 30,000 hours to the 70% lumen maintenance level, assuming operation at 350 milliamps (mA) constant current and maintaining junction temperature at no higher than 90°C. However, LED durability continues to improve, allowing for higher drive currents and higher operating temperatures. Specific manufacturer data should be consulted because some LEDs available today are rated for 50,000 hours at 1000 mA with junction temperature up to 120°C.2

What features should you look for in evaluating the projected lifetime of LED products:
˛ Does the LED manufacturer publish thermal design guidance?
˛ Does the LED lamp design have any special features for heat sinking/thermal management?
˛ Does the fixture manufacturer have test data supporting life claims?
˛ What LED life rating methodology was used?
˛ What warranty is offered by the LED manufacturer?

Source: EERE

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What are light-emitting diodes (LEDs)?
An LED is a very small (dot-sized) electrical device that produces light through the semi-conducting properties of its metal alloys. LEDs have been around since the 1960s, but were used mainly as simple indicator lamps in electronics and equipment. White LEDs are now approaching performance levels that make them attractive for use in automobiles, aircraft, elevators, and some task light applications.

What is solid-state lighting?
Solid-state lighting (SSL) uses semi-conducting materials to convert electricity into light. It is the first truly new lighting technology to emerge for many years. SSL is an umbrella term encompassing different types of technologies including light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs). While both technologies are evolving rapidly, LEDs are the more mature technology, particularly for white-light general illumination applications.

Are LEDs available for general lighting?
A variety of white LED products are available on the market including desk and under-cabinet lights, flashlights, head lamps, outdoor pathway lights, and decorative string lights. For most illumination applications, however, white LEDs cannot yet compete with traditional light sources on the basis of performance or cost. Colored LEDs are often cost-effective and offer energy efficiency and durability for traffic signals, exit signs, commercial signage, and other indicator applications.

Are white LEDs energy-efficient?
The best white LEDs are similar in efficiency to CFLs, but most of the white LEDs currently available in consumer products are only marginally more efficient than incandescent lamps. Lumens per watt (lpw) is the measure of how efficiently the light source is converting electricity into usable light. The best white LEDs available today can produce about 45-50 lpw. For comparison, incandescent lamps typically produce 12-15 lpw; CFLs produce at least 50 lpw. Many LED products use only a small amount of energy, and therefore may appear energy efficient, but they often have very low light output. True energy efficiency means using the most efficient light source or system that is capable of providing the amount and quality of light needed. On-going research and development efforts are making steady progress in improving the performance of white LEDs to levels suitable for general lighting applications.

Source: EERE

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Luminous efficacy is an important indicator of energy efficiency, but it doesn’t tell the whole story, particularly with regard to directional light sources.

Due to the directional nature of their light emission, LEDs potentially have higher application efficiency than other light sources in certain lighting applications. Fluorescent and standard “bulb” shaped incandescent lamps emit light in all directions. Much of the light produced by the lamp is lost within the fixture, reabsorbed by the lamp, or escapes from the fixture in a direction that is not useful for the intended application. For many fixture types, including recessed downlights, troffers, and under-cabinet fixtures, it is not uncommon for 40-50% of the total light output of the lamp(s) to be lost before it exits the fixture.

LEDs emit light in a specific direction, reducing the need for reflectors and diffusers that can trap light, so well-designed fixtures and systems using LEDs can potentially deliver light more efficiently to the intended location.

For example, several manufacturers have introduced LED systems for lighting refrigerated display cases in grocery stores. These products are currently based on white LEDs with lower luminous efficacy than the fluorescent lamps they are designed to replace. But because the system design takes advantage of the directional nature of LEDs and their especially good performance under low temperatures, they are demonstrating energy savings of 50% or more compared to standard fluorescent case lights.

Source: EERE

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You can attach videos and photos stored on other websites at our Forum. Our Forum supports more than 70 different videos, music and slides formats! This will add a new dimension of multi-media fun and interactivity here. The maximum width of a video or photo recommended here is 450 pixels. We use the latest technology to accept popular image and video formats at this website.

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