Taking a fresh look at CFLs
August 1st 2004 Light sources continue to evolve, offering building operators more opportunities to make use of the most efficient lamps available. A technical spokesperson for Megaman (UK) explains why its worth taking a fresh look at compact fluorescent lamps
In the development of lighting systems, it is the lamp that leads the way and the luminaire that follows. Time and again, lamp manufacturers have developed innovative lamps and luminaire manufacturers have come up with designs that make the best use of that lamp.
In that respect, the two go hand in glove, but it is the lamp that makes all the difference to the performance of the lighting system and its cost of ownership. Energy-efficient, long-life lamps are a vital ingredient in the constant drive to optimise overheads and reduce impact on the environment. Yet its very easy to take the lamp for granted because it is generally the luminaire that is most visible.
A familiar example of how a lamp can evolve is seen in the, now common, compact fluorescent lamp (CFL). Hailed as a major breakthrough when it was first introduced, the CFL still took quite a time to get established as a standard product for both commercial and residential lighting. Now, the full potential of the CFL is being exploited with innovative designs that add even greater functionality to the concept and broaden its uses into many new applications. Floodlighting, accent lighting and even high bay and low bay lighting are just some examples of these.
The principle of the CFL is based on the same essential mechanisms as the long-established linear fluorescent lamp. The challenge for manufacturers has been to pack that light-emitting tube into a smaller space by bending the tube, while maximising light output and keeping the operating temperature to acceptable levels. Early CFLs were available in a limited range of options and with relatively low light outputs and many people have retained that image of the CFL to this day.
However, with better designs, advanced engineering techniques and improved mixes of the phosphors used to coat the tubes, CFLs have improved vastly in their performance and diversified greatly in their application. In many situations they also offer a straight retrofit for other types of light source, enabling building operators to upgrade lighting to a more efficient design with minimal capital outlay and disruption. It is for these reasons that its worth taking a fresh look at CFLs.
In all of their diverse forms, CFLs offer high energy efficiency and long life and it is these benefits that have made them so popular. The benefits of energy efficient lighting in reducing electricity bills are now well-established but many people overlook the significance of longer life.
The most obvious benefit is that longer life means longer re-lamping cycles and, therefore, lower maintenance costs resulting from buying and stocking fewer lamps and reduced labour times for operatives. In addition, because most re-lamping requires accessing luminaires at high level, there are health and safety benefits. Less frequent use of ladders and other access equipment reduces the paperwork associated with health and safety issues for employees and sub-contractors, as well as reducing the statistical chances of an accident.
Thanks to the improvements in phosphor mixes, CFLs now offer much better colour rendering than their forebears, making them suitable for a wider range of applications where good colour rendering is essential. These include retail areas where goods are displayed, assembly areas where components are colour coded and a variety of commercial applications where more and more documents are now produced in colour.
New designs of CFL include lamps with an integral reflector to provide better directional light for accent or feature lighting. The most advanced versions of these even use the same lamp base as halogen spotlights so they can be directly retrofitted to existing spotlight installations. Such an upgrade will make the whole system more efficient and less maintenance intensive and will also reduce the heat levels in the area. Halogen spotlights emit a great deal of heat and, in retail environments particularly, this increases the cooling loads for the air conditioning, using even more energy.
Light output has also been significantly increased in CFLs, with some going as high as 300W to give a lumen output of 24 000. Among the most innovative high output lamps are those that incor.porate four plug-in CFLs in a single unit, providing the potential to replace less efficient lamps traditionally used for many applications where a high light output is required. For example, one of these Jumbo lamps incorporating 4 x 18W CFLs can provide a direct replacement for a 200W mercury lamp in a low bay or high bay application. This provides a saving of 128W for each lamp with no compromise on performance, and with a life of 30 000 hours there are big savings on maintenance.
Similarly, high output CFLs can now be incorporated into floodlights that would usually use incandescent or high intensity discharge lamps. These provide a much more efficient solution for applications such as security lighting, lighting of construction sites, car parking areas and many other outdoor applications.
One of the criticisms that used to be levelled at CFLs was their visual appearance, and the problems with glare that could be caused by the high intensity of light from the coiled tubes. Many modern designs now contain the fluorescent tubes within a decorative envelope, such as a glass dome or candle shape. This helps to diffuse the light to prevent glare, while also offering the same design flexibility as traditional incandescent lamps have done in the past.
The examples discussed here just touch the surface of the potential for compact fluorescent light sources in a diverse range of applications. More articles from Megaman (UK )Ltd: | 
