In different industries, LED efficiency has different meanings; becoming more important the longer the lights are on, and therefore making it pivotal for sports lighting. For instance, high bays, such as those in warehouses which run 24/7, have a much greater energy saving potential than sports lights which are running for five hours per week.
Sports lights can be as efficient, but will then cost more, so the savings in energy would be offset by a 30-40 per cent increase in purchase price. The situation, therefore, has to be assessed to get a middle-ground of upfront costs versus on-going usage costs.
A sport light is potentially only used for a few hours a week so it needs to put as much light on the field as possible, without creating a lot of spill. Thus, the actual lumens/watt becomes much less important.
There are a number of components which go into making up a good LED lamp. This involves the removal of the heat (heatsink), quality and type of the LED chip used, cabling, junction box design, optic control, and optic material. All of these factors contribute to efficiency, positively and negatively.
Legacy Lighting has looked at the most important factors in turn:
Heatsink
Powered LEDs generate heat, andthis heat needs to be removed otherwise the LED will be damaged and will produce less light. This cycle will continue until it stops working altogether. The heatsink therefore needs to be designed to draw away the heat and dissipate it, whatever the ambient temperature is. In order to reduce costs, manufacturers can reduce the amount of heatsinking. This results in LEDs running hotter and therefore generating less lumens/watt.
LEDs
Most of the branded LEDs are of similar quality but every LED (of which there are 100’s) have specific characteristics which need to be matched to the application. A large part of LED efficiency is derived from the LED selection and needs to be done by a qualified engineer.
Optics/Lighting control
There are two main ways to control the light which comes out of an LED – an optic or a reflector. Both have advantages and disadvantages and they can be tailored to meet a desired result. Again, efficiency will be affected by the choices made in the optic/reflector design. The optic needs to be designed in conjunction with the LED chip being used as they need to complement each other once put together into a system.
Optic material
Different materials have different characteristics like acrylic, polycarbonate or glass – all of which are common in LED lighting. Acrylic is brittle and has high optical clarity, easy to mould, and doesn’t discolour with age. Polycarbonate is mechanically stronger, but subject to discolouring unless a UV agent is added at the time of manufacture. Glass is very good optically but is difficult to mould and really on suited to flat applications.
When all these factors are brought together into a lamp (or system) a resultant efficiency can be determined. Many manufacturers will claim their efficiency as being the raw output of the LED as specified by the LED manufacturer. However, this is very different to the system efficiency. Once all the above mentioned uncertainties are factored in, it would be common for LED efficiency to be reduced by 30 per cent once in a system.
This sponsored article was brought to you by Legacy Lighting.
