| The Future of Lighting? |
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By Claus Koch As we strive to reduce our energy consumption, for both economic and environmental reasons, it is important to recognize that lighting represents a very large percentage of most commercial and institutional end-users electricity demand. The IESNA (Illuminating Engineering Society of North America) reports that 20-25% of energy used in buildings is for lighting purposes and specifically in the US lighting accounts for 5% of total energy consumption. The heat produced from lighting also accounts for a further 15-20% of the cooling load for commercial buildings. It is noteworthy that we have relied on the lightbulb for almost all our lighting needs for nearly a century. The replaceable vacuum tube, which first made radio broadcasting, televisions, radar and telephones a possibility, lasted only fifty years before being abandoned in favour of solid state electronics that last longer and are more energy efficient. Yet, until very recently there seemed to be no similar substitute for the lightbulb itself. With recent legislation changes and technology advancements, this may be about to change… Light emitting diodes (LEDs) are not a new invention in and of themselves. They have been around for approximately thirty years in various applications and are certainly more efficient: they use a fraction of the electricity compared with lamp light sources; they last five to one hundred times as long as lamps; and they cost less to install. However, LEDs currently only produce colour lighting and therefore their use have been limited to speciality applications such as monitoring and signal lights. Science & technology have progressed some way towards overcoming this obstacle, thanks to the invention of the blue laser by Dr. Shuji Nakamura. It is now possible to manufacture blue LEDs, coated with a phosphor, that produce “white” light. However, the very nature of these “white” light LEDs means they actually cause some loss of efficiency, as compared with the earlier colour LEDs. There are rumours of high performance “white” LEDs, with a range of 300 and 500 lumens per watt (performance measure of visible light produced per unit of electrical draw), which would make them a desirable alternative to the lightbulb. Table 1 shows the typical performance ranges of actual market products from large suppliers:
Table No 1 – Typical Performance of Lighting Solutions As can be seen from the above table, the cost of white LEDs far exceeds that of conventional light sources, and the actual cost of the most recent LEDs is still unknown. The cost factor initially suggests that LEDs will never be a viable alternative to the lightbulb. However, if we apply Moore’s Law to this example, the future of LEDs looks brighter. Moore’s Law, proposed in 1965 by Gordon Moore, states that the cost of semiconductor performance falls in price by 40% annually. For example, a memory board that can store one megabyte of data may have cost $1000 at one time; 10 years later one megabyte would cost about six dollars. LEDs (also solid state devices) have been exhibiting similar price/performance improvement and are expected to continue this trend. As the issue of cost erodes away, the inherent benefits of LEDs make them an increasingly attractive substitute: no mercury content, inexpensive ingredients, safer operating temperatures, instant on/off switching, no cold temperature start-up problems, no ultraviolet light to fade fabrics, no infrared to add unwanted heat, high directionality for display lighting, reduced land fill, and generally lower maintenance costs. There are, of course, still a number of challenges that must be addressed before we see LEDs becoming our primary light source. Amongst them is the highly directional nature of LED lighting. This is good for task lighting but is not so good for general illumination. Using these point sources to produce indirect lighting increases the cost of the installation and reduces the performance. The low output per LED requires banks of LEDs to produce the same light as one conventional lamp. Another possibility is that LEDs may be superseded by other photo luminescent technologies that are now reaching the market. In summary, LEDs may well be the future of lighting, but today’s product line-up is best suited to fill a growing list of niche applications. Because lighting technology is complex and multi-faceted and because it has significant impact on the bottom line, consumers are advised to seek objective expert help for their lighting needs. Energy Advantage is in position to properly assess their client’s needs and deliver real solutions with real savings. Contact Energy Advantage at 1-800-354-1266 to learn more about lighting projects that will work for your company. Editorial Contacts:
Dan Morel |
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