21 June 2018
Super-Efficient LED Lights Hailed as the Future of Electric Lighting
If you have ever attempted to change a defunct lightbulb immediately after its demise, you were probably made painfully aware that most of the energy it consumed was converted to heat rather than visible radiation. Following Edison’s early attempts to create an incandescent electric lamp, efforts to improve it focused almost entirely on extending the life of the filament and increasing its brightness, with little thought for its thermal efficiency. Today, LED (light-emitting diode) lights are the result of a more recent change in that focus, which was made necessary by growing environmental concerns.
The efficiency of electric illumination can be measured in terms of how many lumens it is able to generate for each watt of electrical energy used. For a tungsten filament globe, that figure ranges from 10 to 17 lumens per watt, and these devices have an average working lifespan of around 1 000 hours. With the goal of improving the brightness of incandescent lamps, a previously proposed idea of mixing small amounts of a halogen gas, such as iodine, with the inert gas surrounding the filament was patented in 1959 and the first tungsten halogen lamp was launched. An improvement at between 12 and 22 lumens per watt, its performance remains far short of the LED lights that seem likely to replace all other forms of artificial lighting.
Heat continued to be a problem and, in fact, halogen lamps have since been adapted to power cookers. In parallel, work on a new type of lamp that employed electrodes in a vacuum tube to excite a coating of fluorescent material saw the launch of fluorescent lamps in the ‘30s and though markedly cooler than other available options, their large size and tendency to flicker remained a drawback until the development of the modern CFL or compact fluorescent lamp. With an output of between 40 and 70 lumens per watt and an average lifespan of between 6 000 and 15 000 hours, CFLs are the closest contender for the crown still held by LED lights.
Luminous efficiency is undoubtedly the most obvious benefit of these new devices. Even more compact, they take over at the point beyond which CFLs fail, and they are able to produce a massive 70 to 100 lumens per watt. What is not immediately obvious, however, is that light-emitting diodes also have an extended lifespan. Offering a massive 50 000 hours of active use, there is, in fact, no product to compete with the overall, efficiency and economy of LED lights.
Although initially expensive, improved manufacturing technology has seen the price of these products fall dramatically, and it is now possible to recover the cost of replacing all the exiting globes in a home with these within two years, based on reduced energy consumption. The lower operational costs have led to their use in street lighting and traffic robots, where the use of multiple diode arrays means that should one or more fail, this will not jeopardise their continued performance.
Available in almost pure white or warm shades, there’s little doubt that, while CFLs are a little cheaper, light-emitting diodes offer greater long-term economy and are destined to dominate the future. Eurolux is helping South Africans embrace that future with our extensive range of quality LED lights.