LED advantages (and we’re not talking power efficiency, nor average lifespan)
The image that we usually have of LED lights is linked to their high efficiency and their long shelf life and, thus, we don’t even think of other advantages they can offer. Let’s see some of them:
Traditional light sources cast radiation in all directions. Because they are mounted on a flat surface, LED lights cast radiation towards only one hemisphere. In both cases, for most applications, casted light must be directed through the use of lenses and/or reflectors, which represents a loss of efficiency. In this sense, LED starts up with an advantage, because part of the lights direction is already in it, which means that, on the whole, its optical system is more efficient.
In contrast, with applications that require an omnidirectional light, LED poses more problems. That’s the reason why, in some cases, fluorescent lights are a more convenient option.
Due to their small size, in general LED allow for a more efficient design of lights and reflectors.
The small size of LED has shaken up the design of luminaries. It has also contributed to the integration of lightning to architecture, and has opened new scopes of application. Still, we need to also assess the restraints linked to the need to evacuate the produced heat, because, in many cases, the dissipation ends up being bulkier than the light source proper.
However, “small source” is only a half truth: even though it’s true that, for relatively moderate power, the LED solution is usually smaller in size —in light flux— than its conventional equivalent, for very high power the ratio is inverse. There are luminaries with discharge lamps of over 20,000 lumens that take up less space than a LED with identical flux.
The LED has no filaments, nor it’s contained in a bulb, which rules out the main cause of breakage of traditional light sources. This is a very important aspect in applications in which lights are exposed to impacts (sports grounds, vandalism areas, etc.), where there is vibration (means of transportation, machinery, etc.). And, above all, it reduces the incidences during its transport and installation, the processes in which most breakages occur.
Instant switch on
Discharge light sources –which, after the LED, are the most efficient— do not switch on immediately. There are even some that don’t get to cast a hundred per cent of their light flux until some minutes have past. Furthermore, there are some, like the metal halide and sodium-vapor lamps, that need a low temperature to be able to switch on. In case of accidental shutoff, they can require several minutes to cool down and start up again.
With the LED, that doesn’t happen, leading to an aesthetical, functional and safety advantage.
Turn on/off cycle without negative effects
The turn on/off cycle doesn’t shorten the lifespan of the LED, opposite to what happens, for example, to the fluorescent lamps. In fact, it is very usual that these end up having a much shorter life due to their use in areas with constant switch offs —stairways, private bathrooms, etc…—, due to the user’s lack of knowledge.
Absence of ultraviolet and infrared radiation
Besides leading to a bigger efficiency, the absence of UV and IR radiations allows to light up delicate surfaces —art works, clothes…— while minimizing the harm.
One should not mistake the absence of infrared radiation for lack of heat. LED, even though they don’t produce IR in their light beam, do produce heat, which ends up dissipating mainly through their back side.
Anyway, if we want to remain critical, we should not forget that what is presented as an advantage is, in most cases, a drawback. If the LED casted infrared radiation, it would mean that part of the heat was being cast through the beam proper, which would partially solve the big problem in the luminaries design: heat dissipation.
Working right in low temperatures
Low temperatures represent a problem for fluorescent tubes, because they lower their performance. On the contrary, LED improve their performance with cold temperature. That’s why their use in cold atmospheres —refrigerators, cold storage rooms, outdoors— is highly recommended. Instead, its use is discouraged in high temperature areas, where their performance is cut down (especially their lifespan).
Discharge lamps presented some adjustment problems —or simply, in most cases, they could not be dimmed. LED are dimmable. But the model, equipment and adjustment system must be conveniently studied.
Color change or color temperature
It is feasible to combine multiple type chips in a single product. That fact allowed the proliferation of applications with color change and color temperature that, until the LED appeared, were basically made with the use of filters, always with luminaries of a considerable size.
The door has also opened to the use of white light luminaries of adjustable color, even though they are applications that, for the time being, have a lower degree of market deployment.