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LED lighting update

Posted by Bruce Rowse in Energy Efficiency | Lighting
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LED lighting continues to get better and better, with more and more products now available.

Sydney based company Enlighten now have a “back of house” light suited to carparks, fire stairs and intermittently used corridors that incorporates both high efficiency LEDs and a occupancy sensor to turn the light on and off.

The fitting has a standby lamp that provides emergency illuminance, and when motion is sensed by the microwave sensor the ligth comes to full brightness.  Microwave sensors can “see” through non metalic doors or walls, and the fitting can theoretically be set up in a corridor to turn the lights on as someone approaches the entry door on the other side, making it appear as though the lights are always on!

Energy savings are achieved from both the higher efficiency of the LED fitting and the sensor. Depending on the amount of movement, this can provide energy savings of 90% plus.

We also have in the office some Osram LED downlight halogen replacements. They have excellent light colour, with a 10 watt GU10 LED substituting a 50 watt dichroic or a 35 watt IRC lamp. The lamp is longer than a standard halogen, which in some cases may make the installation awkward, but otherwise this is a good light, although it may not be quite as bright as a 50 watt halogen. A MR 16 version will be out soon too.

We have tested many halogen replacements over the years, they are getting better and better, and now the major brands are coming out with these it provides buyers more certain about performance and longevity.

LEDS magazine has provided some recent updates on LED technology. Fully “packaged” LEDs are now commercially available with efficacy’s approaching 100 lumens/watt. To put this in context fluorescent lighting, the most efficient form of general purpose lighting, gets up to 105 lumens per watt. The advantage of LED is that the light is directional, providing more useful light.

According to the US Department of Energy (DOE) packaged LEDs will reach 253 lumens/watt by 2020.

Pricing is also on a downward trend. Price is now around USD $50/1000 lumens, compact fluorescents are now at about $5/1000 lumens, or $10/1000 lumens if dimmable.  DOE predicts prices will be at around $5/1000 lumens by 2020, with $10/1000 lumens reached by 2015.

Clearly by 2020 LEDS are likely to be the only lights around, and DOE has set a target for a “smart” troffer fitting to be $85 by 2020. Based on this achieving around 250 lumens/watt, this troffer will use around 20 watts to achieve similar light output to a typical 2 x 36 watt fluorescent troffer now in use.

LED chip manufacturer CREE have reported achieving 231 lumens/watt for an LED module in their R&D lab.

There is now a global trial of LED street lighting underway called the “Light Savers City Trial”, involving amongst others the cities of New York, Toronto and Sydney. Preliminary results are promising. The trial is pretty rigorous, with the New York trial involving the monthly measurement of road level illumination, colour temperature,  ambient temperature and power consumption.

The National Gallery, London, is now upgrading to indoor LED lighting following a trial. In addition to energy savings (equivalent to around 400 tonnes of greenhouse gas annually), the LEDs to be used have no change in colour temperature when dimmed (unlike tungsten lamps), have a longer lifetime, and don’t produce any UV light.

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