Examples of uses for LEDs
As the quality and efficiency of LEDs is improved it will be possible, within a few years, for them to dominate homes, offices and streets in both the private and public sector. You can see examples of uses for LEDs below.
Equestrian statue in Copenhagen
Jogging path lit with LEDs
Street lighting in Horsens
Toronto flash
Aarhus Concert Hall's extension
LEDs in a cold store
LEDs in freezer display cabinets
Turning Torso in Malmø
Rosenborg Castle
Traffic lights
Elevator lights
Petrol stations
Equestrian statue in Copenhagen
The new lighting in the area around Højbro Square in Copenhagen is a good example of how LEDs can be successfully used for outdoor lighting in city environments. The lighting was created in a partnership between lighting designer Jesper Kongshaug and Philips Lighting.
The focal point of the lighting is the equestrian statue and the accentuation of Højbro Square with the lines of trees. There are 44 LED uplight luminaires embedded in the ground under the two rows of trees that stretch from the equestrian statue by the canal to Amagertorv. These illuminate the trees from below and create a framework around Højbro Square. Each of the 44 luminaires is equipped with 6 K2 LEDs. Total power consumption is 792 W (880 W incl. driver power loss).
The equestrian statue is lit partly by a 60-metre-long LED string attached to the plinth of the statue, and partly by 4 Beamer LED spots located on the surrounding buildings. The total power consumption of the 60-metre LED string is 200 W (220 W incl. driver power loss), with the 4 spots rated at 12 W (16 W incl. driver power loss).
The LEDs in the string are a combination of cold white diodes with a colour temperature of 6,300 K and a number of amber-coloured LEDs. This colour combination makes it possible to vary the colour temperature 2,700 and 6,300 K.
The lifetime of the LEDs used is 50,000 hours for both diodes and drivers, with a 30% reduction in light output. By using LED lighting instead of traditional light sources, such as metal halogen, the power consumption is reduced by 40-45% according to Philips Lighting.
The square also features lampposts designed on the basis of the original lighting, but equipped with reflectors and light sources which effectively direct light to areas where it is required. Back to top
Jogging path lit with LEDs
The Jogging path in Mølleparken, Aalborg is lit with LOA LED bollards, a specially designed luminaire that illuminates the path but not the surroundings. Photo: Gunver Hansen
The primary reason why LEDs are suitable for outdoor lighting is that they function optimally in low-temperature surroundings, irrespective of how cold it gets.
When Eskild Hansen and Gunver Hansen were given the task of designing a luminaire for a jogging path, the use of LEDs as a light source was an obvious choice. The result, developed in cooperation with Philips, is called the LOA LED bollard. This is flexible and can be set up to illuminate in 2, 3 or 4 directions. This means that the bollard is particularly suitable for lighting paths, both straight stretches and where they fork in several directions.
LOA LED bollards were used for the first time for lighting this new jogging path in Mølleparken, Aalborg. The bollards are equipped with 5 Philips LMS 3W LEDs and a Xitanium LED driver. Each bollard has a combined power consumption, incl. the driver, of 17 W. The jogging path is 2.5 km long and is lit by a total of 101 bollards.
Once the lighting system was installed, all the LED modules in the 101 bollards were individually tuned to provide the right distribution of light on the path. In comparison, equivalent bollards normally use 18 W or 26 W fluorescent tubes or 35 W metal halogen lamps with traditional light sources. Back to top
Street lighting in Horsens
The top picture shows the old street lighting. The bottom picture shows the new lighting provided by lamp posts fitted with LEDs. The replacement was carried out at the same time as the laying of new underground cables. Photo: Energi Horsens
November 2007 saw the inauguration of Denmark’s first street lit by LEDs. In all, 16 new lamp posts with 65 W LED luminaires were installed in a street in Horsens. According to LedTraffic the new lighting results in savings of 20-30% when compared with traditional street lighting with metal halogen lamps.
The luminaires developed by LedTraffic in partnership with Energi Horsens are equipped with power LEDs with a colour temperature of 3,000 K and a lifetime of 50,000 hours based on a luminous flux reduction of 25-35%.
LedTraffic has also tested street light fittings in several major European cities. By the end of 2007, 3 more stretches were equipped with new street lamps: 1 in Norway, 1 in Sweden, and 1 in London. Although the first versions of the street light fittings had an efficiency of 70 lm/W and a CRI of 65, the new versions have an efficiency of 90 lm/W and a CRI of 85. Back to top
Toronto flash
Replacing incandescent bulbs with LEDs in pedestrian crossing lights has resulted in lighting improvements and significant savings. Photo: Lysteknisk selskab
It makes sense to use LEDs for this type of lighting, in which an LED’s forward light projection and its inherent capacity to produce coloured light can be utilised. This is why replacing traditional light sources with LEDs has been a reality for several years.
There are considerable savings to be made based on energy consumption alone. Most zebra crossings with flashing lights; the so-called 'Toronto flash', were previously equipped with 100 W incandescent lamps. During 2006, Dong Energy replaced the incandescent lamps in 1000 Toronto flashes in Zealand and Copenhagen with 13 W LED flashes supplied by Dansk Trafik Teknik A/S. As a result, annual electricity savings of 128,000 kWh (87%) were achieved.
To this should be added savings on maintenance. The lifetime of the amber LED flash is typically 40-50,000 operational hours, which means they only need to be replaced once every 10 years. The previously used incandesent lamps needed to be replaced approximately 4 times a year.
All in all, electricity and maintenance savings result in a return on investment period of 6 years, based on electricity costing just under 9 eurocents per kWh. Back to top
Aarhus Concert Hall's extension
Ingvar Cronhammer's LED chandeliers and wall lights from Thorn illuminate the foyer in the new extension to Aarhus Concert Hall. Photo: Lars Hjorth, Pablo Diversity ApS
The lighting in the foyer, corridors and stairs in Århus Concert Hall ’s new extension was carried out exclusively with LEDs. The building was extended in November 2007 and the foyer is lit with large LED chandeliers designed by the artist Ingvar Cronhammer.
In all, a total of 17 chandeliers were installed, each with a diameter of 1.2 metres. Each fitting contains 217 white power LEDs with a total power consumption of 280 W. It was important to have lighting with a relatively warm tone. This was achieved using warm white LEDs from 3 different bins to achieve a colour temperature of 2,900 K, which is very close to the light colour of incandescent lamps. The fittings have a CRI of around 83 and a luminous efficiency of 42 lm/W.
The fittings can be dimmed (0-10V) with an adjustable range of 5-100%, without change in the colour temperature. Apart from the lamps’ downward focused white light, a row of red LEDs have been placed round the rim on top of every lamp. The red diodes create decorative red reflections on the polished ceiling above. 65 wall lamps from Thorn, also fitted with LEDs, were installed in the walking areas and stairs. The wall lamps are an existing design fitted with 18 power LEDs with a total output of 23 W per fitting. Like the chandeliers, the colour temperature is 2,900 K with a CRI of 83.
The chandeliers and wall lamps were produced by Pablo Diversity ApS who confirm that the thermal parameters in both luminaires are good. In particular, the chandelier is thermically well designed with the junction temperature of the LEDs lying at around 50 °C at maximum luminosity. Because the fittings are made of aluminium the thermal design of the wall lamps utilises a junction temperature of around 70 °C at maximum luminosity. Back to top
Cold store with LED lighting at Chr. Hansen. Photo: Chr. Hansen/Lumodan
As previously mentioned, LEDs function optimally at low temperature and moreover light up immediately, so they are the obvious choice of light source for lighting in cold stores and other low temperature environments.
The first and largest installation in Denmark in which this type of lighting from Lumodan is being used is on the premises of the ingredients solutions company Chr. Hansen, which installed LED lighting in its 1,000 m2 Avedore cold store, which is chilled down to ˗55 °C.
The company previously fitted incandescent lamps which used a total of 20 kW. Tungsten filament bulbs were the only bulbs that were able to operate at such low temperatures. But with LEDs installed the total power consumption is 5.5 kW, which results in energy savings of 72%. Moreover, a lot less energy is used for refrigeration because LEDs do not produce the same amount of heat as incandescent lamps.
The LEDs used have a colour temperature of 6,500 K and produce illuminance of 130-150 lux, compared with the 50-70 lux previously achieved. Back to top
In In November 2007, Novo Nordisk installed LED lighting in a new 300 m2 cold store in Bagsværd near Copenhagen. LedTech supplied 17 ceiling luminaires, each with 1,150 LEDs with a power consumption of 60 W per luminaire. The colour temperature is 4,500 K, which is achieved by mixing LEDs of 6,000 and 3,000 K in a respective ratio of 75% to 25%. The lifetime of the LEDs is 50,000 hours with a CRI of 85.
Novo Nordisk also saved large amounts of energy. Previously, the fluorescent tubes were often left permanently on in the cold store because the start-up time at low temperature was too long. By comparison, LEDs light up immediately which means the lights can be switched on and off as required.
According to LedTech, if you take the above into consideration and assume that the new LED lighting will only be switched on for 2 hours per day, then the return on investment period will be under 1 year. Novo Nordisk is in the process of installing this type of lighting in an additional 1,200 m2 of cold store space and corridors. Back to top
LEDs in refrigerated display cabinets
Wal-Mart in the USA has installed LED lighting in refrigerated display cabinets as part of a major energy saving review. Photo: GE Lighting
The American supermarket giant Wal-Mart has worked intensively to identify areas which will provide the chain with the most energy savings. One of the areas identified is lighting in refrigerated display cabinets. The previous lighting consisted of integrated fluorescent tubes that burned 24 hours a day.
LEDs can tolerate being switched on and off frequently, and produce their full light intensity immediately. They were therefore the obvious choice for a trial of new lighting in the chain’s refrigerated display cabinets.
Working with Watt Stopper, Wal-Mart engineers developed LED lighting with movement sensors, which were tested for the first time in two of the chain’s stores. The systems in each supermarket were connected to a data logger which registered data over a period of 6 weeks. In order to save as much energy as possible the movement sensors were set at a delay of 30 seconds.
This revealed that the LED lights in the refrigerated display cabinets in the 2 stores were switched off respectively 44% and 47% of the day. If one calculates that the lights in a refrigerated display cabinet are switched off 40% of the time when the store is open, and also include savings as a result of reduced cooling requirements, then Wal-Mart estimates combined future savings to be 92%. Wal-Mart is currently installing LED lighting in a total of 450 stores with an estimated return on investment period of 2 years. Back to top
Turning Torso in Malmø. Photo: Louis Poulsen Lighting´
Turning Torso, the 190-metre tower block in Malmø, Sweden, has one of Europe’s largest LED installations. All the corridors in this curved building are equipped with LED panels, and the aim was to integrate LED lighting as an alternative to traditional solutions with fluorescent tubes.
To solve this task, which required 100 lux on the floors of corridor areas, Louis Poulsen developed a reflector profile that both directed the light from the LED down into the corridor area and simultaneously conducted the heat from the LED away. The modular construction of each curved LED panel contains 12x1.2 watt LEDs per metre and therefore meets the requirement of providing the corridors with panels on both sides.
The advantage of this solution is lower energy consumption than for an equivalent fluorescent tube installation, significantly lower building-in height and a longer lifetime, as well as very uniform lighting. A total of 15,000 LEDs were installed in Turning Torso. Back to top
LEDs are gentle on objects which are sensitive to UV rays. LEDs are therefore suitable as light sources for spot lights in museums. Photo: Lumodan
The ‘Queens’ dresses’ exhibition at Rosenborg Castle in Copenhagen was lit with LEDs. These were chosen on the basis of their small dimensions, and especially because LEDs produce no ultraviolet or infrared rays, which degrade the old fabrics. Back to top
Typically, 2x1 watt LEDs were used inside each display cabinet, powered by batteries which lasted 4-6 days. Previously, 35-50 W halogen lamps were mounted outside each cabinet. Photo: Lumodan
A traffic light with LEDS in Odense, which has chosen H.C. Andersen to show when it is safe to cross. Photo: Lysteknisk Selskab
In 2003 the Danish Environmental Institute (now part of the Secretariat of the Danish Economic Council) produced a report on energy savings for LED traffic lights in Denmark and calculated that the return on investment period for traffic lights with LEDs was 6-7 years based on the additional cost of LED traffic lights being around EUR 470. The report predicted that the additional cost will fall in the future due to price reductions in the cost of LEDs.
California has carried out the most comprehensive replacement of traffic lights. All traffic signals in 55 towns have been replaced with equivalent LED powered traffic lights. The project, which received US government financial support, will result in savings of 6,632 MW.
In Pasadena, 1,688 traffic lights were replaced at a cost of USD 926,229, but the energy savings alone produced annual savings of USD 109,000, which equates to a return on investment period of 9 years. To this should be added cost savings associated with replacement and maintenance.
Moreover, there is a significant improvement in safety, in that the old incandescent traffic lights would typically burn out, causing problems when the lights stopped working. There’s no such risk with LED solutions, which use many LEDs in each signal, which don’t stop working, and which have a considerably longer lifetime. Back to top
Photo: Westinghouse Lighting Corp.
Westinghouse Lighting Corp. converted an elevator at the LRC (Lighting Research Centre in New York) to LED lighting. The conversion showed that it was possible to save 45% of the energy consumption by switching from halogen lamps to LEDs in elevator lighting environments, thereby achieving a lifetime improvement from 1,500 hours to around 40,000 hours.
A partnership with another elevator manufacturer, Otis Elevator, showed that switching from incandescent lamps or fluorescent tubes in elevators can save 4-6 inches in elevator height, which reduces both the elevator construction costs and energy consumption used to drive the elevator up and down. Back to top
Q8 has switched to LEDs in many of its petrol stations, thereby achieving considerable savings. Photo: Osram
Many petrol stations around the world have replaced their fluorescent tube signage lighting with LEDs. In Denmark, the oil companies Q8 and F24 have replaced the signs on many of their petrol station sites and have achieved energy savings in lighting in the order of 80% compared with previous installations. Similar savings have been made abroad, where savings of up to 90% have been achieved.
BP has replaced the neon signs in 5,000 of its 17,000 petrol stations in the USA and has saved 25 MW since it switched to LEDs. In addition there are environmental savings, because LED lighting does not use mercury, which is found in both neon and fluorescent tube lighting. Q8 was awarded the Greenlight Prize, which is a European environment prize, for its replacement program. Back to top
Page last updated 06.10.2009