LED Lights Are Lean and Green

by: Robert Louis Arner

Time for Green Lights! The journey of energy independence begins with proper lighting management

It is time we go look beyond just jokes about how many people it takes to change a light bulb. Lighting consumes up to 20% of our home energy and up to 30% our work electricity.

Light-emitting diode (LED) is a 45 year old technology that delivers n heat output and deliver an average of 32 lumens of light, and they burn about 50 times as long as the average incandescent bulb. The Department of Energy estimates that LED lighting could reduce U.S. energy consumption by 29% by 2025, slicing $125 billion off our national energy bill in the process. Recent university research and other advancements have help LEDs to replace incandescent light bulbs in the next five to seven years. Over the last few years there has been advancements increasing the light output per chip. Once you get more light out of the chip, then the cost goes down in terms of how much light it produces.

There are three major types of lights, incandescent, fluorescent and LED. LED is to fluorescent or mercury bulbs as incandescent are to fluorescents in energy savings, duration and cost. Light-emitting diodes (LEDs) are not a new technology (1970s). LEDs offer benefits such as small size, long lamp life, low heat output, energy savings and durability. They also allow extraordinary design flexibility in color changing, dimming and distribution by combining these small units into desired shapes, colors, sizes and lumen packages. LEDs have advanced from use as indicator lights and in numeric displays to a range of innovative and new applications, including accent lights, task lights, traffic lights, signage, outdoor lighting and down-lighting.

LEDs have many useful applications, are on the threshold to revolutionize many new light sources. The advent of great visible/white light LED has awakened lighting industries to new savings, reducing heating costs and minimized maintenance possibilities with this light source. White light LEDs, currently may produce enough lumen output to make them competitive with many general light sources.

LEDs are solid state semiconductor devices and their LED illumination happens when a semiconductor crystal is stimulated so producing visible light. When an LED unit is electrified, a power supply converts AC voltage into sufficient DC voltage, illuminating the diode semiconductor crystal. The LED is sealed in a clear or diffuse plastic lens that can provide a range of angular distributions of the light.

Efficient LEDs are low-voltage, low-current devices and efficient light sources. Phillips Lighting cites, “In 1993 an array of 200 LEDs was required whereas only 18 LEDs achieve the same performance today, with prediction of further reduction to only 10.” Progress continues. Efficacies as high as 100 LPW have already been achieved in laboratory conditions. According to Steve Johnson, group leader of lighting research for the Lawrence Berkeley National Laboratory, “It is not unrealistic to expect the efficacy of solid-state sources to achieve 150-200 lumens per watt in the coming decades.”

Several manufacturers currently offer a range of LED fixtures for replacing MR16 lamps, display lighting, cove lighting, underwater lighting, architectural details and other applications. Designers should carefully consider requisite lumen packages, source brightness, viewing angles and color rendering when considering use of this technology.

LEDs are becoming extremely attractive. As the demand for these lights to conserve more of energy so will the need for greater supply to keep us out of the dark.