by Dr. Karl-Heinz Froehner
verybody is talking about LED lighting these days. LEDs are not new, but now as the industry focuses on manu- facturing the next big thing, LED technology is making great strides. Like with many of today’s high-tech devices and applications, everybody talks about it, but relatively few people actually have an insight beyond some basic under- standing. The world was so easy when we just had the incandes- cent light bulb. Heat a Tungsten wire hot enough and you will get light. Then the fluorescent light made things more complicated and now, of course, there are many other ways to generate light. An LED, or Light Emitting Diode, seems to be the future
E
for lights. We are all familiar with LEDs from various appli- cations—we see them blinking everywhere. Today’s highly developed LEDs, however, are at the forefront of the technol- ogy push everywhere in the world, especially in Asia.
What Exactly is an LED? An LED light is not another light bulb. It actually is an electronic system, not just the LED ‘bulb’, or what is many times referred to as the LED engine. Incandescent lights are designed to be hot, that is after all how they create light, by being really hot. LEDs want to be cold. They actually are very intoler- ant to even relatively low temperatures. Briefly, the reason is that LEDs are made of semiconductor chips. Those little chips fail at higher temperatures. Even if there is not so much power being used by an LED, all the conversion of the power into heat happens in a very tiny space and the only way to rescue the device is to get the heat away from the origin of the light as fast as possible with good heat sinks or cooling of the diodes.
What Makes an LED Work? Without going into all aspects, let us list just a few things that have to be considered when designing and constructing a good LED light: the LED engine, the source, color and density of the light; the mix of wavelength that affects the color rendering and qual- ity of light; the heat management in the fixture; and the electronic controls and the quality of the current to the LEDs. As you might imagine, dimming in LEDs is a whole different ballpark from the dimming of other contemporary lights. It might take a while before we have the infrastructure and the trained workforce to fully implement LEDs and make use of their full potential at the consumer level.
Acting Environmentally Responsible: LED Lights
Can I Use LEDs in My Home? In the meantime, we see many replacement LED lights which take advantage of the existing installations, the lower energy use and longer lifetime of the LEDs (if properly designed and used). Not every application will make sense at this moment, but there are many scenarios where LEDs do make sense and will save money. From the environmental viewpoint, it makes sense to re- place a light with a very efficient LED even when there is no overall cost advantage. In this case the investment is in the LED light instead of the cost for coal and oil to produce large amounts of electricity that are only being wasted to generate inefficient lighting and to cool rooms because the lights are getting so hot.
What is the Future of LEDs? In the very near future, there will be other develop- ments coming to the market. Just to highlight one - LEDs naturally operate with very low direct current (DC). The operation of LED lights with alternating current (AC) is not really efficient. If we generate and supply DC directly to the LEDs we would have much less loss due to inverters, etc. When inverters are needed to convert electricity back and forth between DC and AC, a substantial amount of energy is lost in every conversion. With LEDs, this conversion will not be necessary. In addition, we could generate a very safe electrical wiring system (24V DC) and run the low power LEDs on it along with many other electronic applications. Photovoltaic systems, wind generators and fuel cells could be used to supply buildings with safe, extra low
voltage DC power. In many instances, LEDs are a great
alternative for homeowners and businesses today. And as the technology continues to advance, LEDs likely will become the clear choice for lighting our homes and offices.
Dr. Karl-Heinz Froehner is the president of Rueste International Limited of Wappingers Falls, a developer and manufacturer of low voltage building control systems. He works closely with Thom Woglom of Greenway Technolo- gies of Warwick in helping homeowners be more energy efficient. He can be reached at
info@rueste.com or 233-1187 or
rueste.com.
Photo © EarthLED/
flickr.com natural awakenings October 2011 13
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