THE INSTALLED lighting load at Liverpool Street railway station in the City of London has been halved after the metal halide high bay luminaires were replaced.
Additionally, a control system could cut operational load by 70 per cent.
Liverpool Street railway station in London was built in 1874 and is the third busiest in Great Britain. The station is vast with 18 platforms, an Underground rail network interchange and over 50 retail shops.
The station operates almost 24 hours a day throughout the year. The electrical switchgear and cabling is equally as complex but, being over 25 years old, needed to be replaced.
The contract to replace this equipment was won by SSE Enterprise Rail. Changing the lighting wasn’t originally part of the SSE contract.
However, SSE suggested that the existing1kW metal halide high bays were now outdated and that an LED replacement would result in major energy savings.
Halving the wattage could also save on the size of the cable and switchgear required. There would be further savings in lamp maintenance.
There were two major challenges. The first was ensuring safe and easy access to the luminaires; these are mounted high up under the glass roof.
These positions are fixed and the second challenge was to make sure that the new LED luminaires could be used in the same locations and yet provide better and more energy saving lighting.
The solution was to use the 426W Haloprism high bay from Holophane which delivers 55,000 lumens. This, alone, delivered a 57 per cent saving in energy consumption.
What’s more, the 4000K LEDs have a colour rendering index, CRI of over 80 thus delivering high quality lighting to the station concourse and platforms.
The other big advantage of the luminaire for the project was that, as it’s available in five different optical distributions, they could be replaced on a one-for-one basis.
The torus shaped refractor gives improved ‘volumetric illumination’. Thus the space appears much more light and airy.
The rated life of the LED module is 100,000 hours – that’s an L70/B50 at 30C – meaning that it lasts six times longer than a typical 1kW metal halide lamp.
This longer life coupled with the glass refractors which have high resistance to the dirt found above railway trains means that the frequency of cleaning can also be reduced and the concourse lighting stays brighter for longer.
Fewer maintenance visits also means increased safety because the staff had to have special training, a licence and specialist equipment to access the luminaires.
Network Rail also needed a solution to make it easier for maintenance staff to handle the fitting, if it was required. Above each fitting on the glass roof is a hatch and Holophane designed a mounting bracket with a ‘handle’ that ensures a person can easily grasp the fitting and pull it through the hatch.
The biggest savings come from using a 426W highbay instead of 1kW but there are additional savings being made by using the Holophane Holos wired control system, which has the potential to reduce energy consumption by up to a total of 70 per cent.
This is setup for daylight harvesting and to control the illumination levels in the station. On bright days, the light output from the high bays is reduced, thus saving even more energy.
Other energy saving measures at Liverpool Street Station include the replacement of traditional SON lamps with LED equivalents.
- See the latest LED high bay luminaires at LuxLive 2019, taking place on Wednesday 13 November and Thursday 14 November at London ExCeL. Entry is free – see more information HERE.