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[ Spotlight: Lighting ]

has certainly been a lot of progress in the development of LED technology. As LED technology advances, we are more commonly seeing LEDs being used in every possible way within the electrical and building services industry.

Why so popular – and where do they come from? The introduction of the first high-brightness blue LED and, subsequently, white LED in the 1990s heralded the beginning of the LED era. Since the light output no longer posed a barrier to using this technology, the other benefi ts of LEDs could now be realised. Signifi cantly lower energy consumption and longer life have led The Department of Transportation in California to replace 200,000 traffi c signals with LEDs during the most recent energy crisis. Subsequently, LEDs are now entering the domestic, commercial and industrial sectors with vigour. LEDs are categorised into ‘regular’, ‘high brightness’ and

‘ultra high brightness’ models. It is the high brightness LED that allowed us to approach the 100 lumens per watt barrier in 2009, making this technology a real low energy saving solution within the lighting industry.

Production LEDs are made from a variety of semiconductor materials that determine the colour, and incorporate rare earth materials to allow the device to function appropriately. China supplies 95 per cent of rare earth materials, the prices of which have doubled in light of the country’s recent clampdown on mining, production and exports. Through a complex process the LED structure, with its various components is sealed in plastic known as a ‘package’ by semiconductor companies. These packages can then be incorporated into lighting

products, the design of which must be considered carefully. The thermal management system is critical. Put simply, that is how well the product can dissipate heat. Poorly designed products may result in poor light output – or even premature failure. This is the next step in the process, with assembly companies placing LED products into structures that we recognise, such as lamps and street lights. These products then fi lter into the market through distributors, wholesalers and ultimately the end user.

Technology development LED development is an evolving technology. Currently, no fi xed standards exist for the manufacture of high brightness LED packages, with each manufacturer having its own design. However, as technology improves, the cost of LEDs should fall while light outputs increase – a trend that has developed consistent momentum. This is no better illustrated than by what is known as ‘Haitz’s Law’, which predicts that every decade there will be a fall in the cost per lumen (light output) by a factor of 10, and an increase in light output by a factor of 20. Haitz, who originally predicted the crossing of the 100 lumen per watt barrier by 2010, has also indicated a predicted Lumen per Watt ratio of 200 to be achieved by 2020. This is staggering when one considers the current criteria for low energy lighting is to achieve a minimum 45 Lumens per Watt for domestic applications. Interestingly, it appears that not only have

September 2011 ECA Today 51

Haitz’s forecasts been achieved historically, but they have also been surpassed.

Aside from low energy, there are a number of operational and environmental benefi ts of using LED technology on your future projects

Future So what does this mean for the future? It appears, at least for the moment, that LED technology is due to be the mainstream lighting of the future. Much will depend on government initiatives to encourage the adoption of energy efficient lighting technologies. Government-sanctioned economic incentives, the banning of traditional high-powered lamps, and investment into research and development all bode well for the future of the LED industry. However, it is not only the elected officials who will

About the author

Giuliano Digilio Giuliano Digilio is the head of ECA Technical Services. He has extensive experience in the electrical and electronic engineering building services industry, and sits on numerous technical committees for the ECA in the UK and Europe.

ultimately decide the fate of LED. A trend of increasing energy costs, lower LED prices and improving light output ultimately means that payback periods for any investment made into LEDs by companies or individuals is falling. The US Department of Energy estimates the useful life of high powered LEDs to be as high as 50,000 hours. This extended life contributes to reductions in maintenance costs, in addition to energy savings, making LED lighting an attractive proposition. Significant LED lighting projects are now becoming

commonplace. Airbus and Boeing both showcased planes featuring LED lighting in this year’s Paris Air Show. Seattle has also adopted the technology in street lighting. Only time will tell if LED technology will be ousted by some other form of lighting, or forge itself as a staple in the future. Currently fl uorescent lamps seem to be the only other low energy alternative, and although they are lower in cost, this technology still has the drawback of containing the toxic element – mercury – meaning it must be treated as hazardous waste. For now, it seems that LED technology may be one of the viable long-term solutions.

■ For further information on LED lighting technology, contact Giuliano Digilio at the ECA at giuliano.digilio@ or call 020 7313 4825, or email Dr Michael Dangoor at Orlight at or call 01707 663 883. See or

LED lighting is being put to an increasingly diverse range of uses

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