Recent EuP legislation has signalled the death of the traditional incandescent lamp and has paved the way for compact fluorescents to become the means by which we light our homes. In the commercial market advances in fluorescent technology have improved both performance and efficiency. LEDs have been with us for several decades, mostly for use as indicator lamps in equipment, but over the years this humble little glowing object has developed beyond all recognition. Vast sums of money have been invested worldwide in driving LEDs to new heights and the pace of progress looks set to continue.
2009 saw the introduction of the first high performance halogen reflector lamp replacements and these seem to be improving by the week so that we now have near equivalents to 50W halogen. A raft of new general lighting replacement lamps are starting to appear this year, some claiming to match the light output of a traditional 60W lamp. At the Light and Build Exhibition in Frankfurt in April the Lighting Association also saw see some significant launches from major lamp suppliers which will undoubtedly step up the game further still in the near future.
Justified investment
Currently, the best LEDs come at a price. In the consumer market this has not been at a level that has stimulated significant demand. However, in the commercial world it is a different picture. The long life of LEDs - which brings low maintenance coupled with their higher efficiency - means that payback times for businesses are good and the additional investment is justified. Add to this initiatives, such as the Carbon Trust’s Enhanced Capital Allowance scheme, and the argument gets stronger still. The cost of LEDs are predicted to fall as demand increases and the market becomes more competitive. However, they are not expected to fall as low as incandescent lamps or even the low cost subsidised fluorescents.
The automotive industry has already heavily adopted the technology and most new cars now employ large arrays of efficient LEDs which are better suited to the environment of motoring that traditional filament based lamps. LED street lighting is also appearing in pockets throughout the UK, providing a clear white light rather than the more traditional yellow sodium lights we have become used to with their monochromatic colour rendition.
However, the Lighting Association predicts that the true growth in the LED market in the longer term is not in retrofit lamps but in dedicated LED luminaires. There are many important criteria to consider when building an LED lamp or luminaire and the key one is temperature. Drive them hard and you can deliver a great deal of light for a short time but heat kills the LED in the end. Good thermal management is essential to deliver the promised life of the LED and this is usually easier to provide where the LED is built into the luminaire and a suitable heat sink can be housed, or in some cases the entire luminaire can be the heat sink.
Good quality driver components are also essential to the longevity and performance of the LED. Most failures occurring today are invariably faults with poor quality drivers. Squeezing these components into a small light bulb sized package is always going to be a compromise and it is likely that in the future most of our environment will be lit by luminaires where the LED is integral with the product and not a replaceable lamp. From the point of view of the luminaire designer LEDs offer the possibility for a completely new type of luminaire where they are no longer bound by the dimensions and requirements of a conventional lamp.
Increased light outputs
There are other advantages to look forward to, as light outputs increase and energy consumption decreases. The holy grail in efficiency is currently the 100 lumens per watt lamp which surely cannot be too far away. The Lighting Association recently became aware of a product that claims a measured 84 lumens per watt in a commercially available lamp. Colour tuneable LEDs are another welcome development and a whole new LED technology is also set to change our world in the form of OLEDs. Organic LEDs can be printed onto flexible materials and can be produced in micro-thin panels, will the future offer us wall paper that lights up? The technology is already here to do it.
LEDs are developing at such a fast pace that it is hard to keep up with the progress and attempts to draw up standards and minimum performance criteria are ongoing both in the UK, Europe and internationally.