OSRAM’S Retrofit Lamps Used In Historic Lanterns – LEDs Provide Energy-Saving Period-Style Street Lighting In Regensburg
OSRAM Opto Semiconductors and Siemens have
demonstrated that energy-saving LEDs can provide authentic
period-style lighting to illuminate a historic centre. The companies
have developed a retrofit solution which meets the requirements of a
modern lighting system while preserving the atmosphere of a world
heritage site. High-power Golden DRAGON® Plus LEDs have been
discreetly installed in the luminaires prescribed by the Office for
the Preservation of Historical Monuments. These LEDs target the
precise spot they are intended to illuminate, thus avoiding light
Regensburg has narrow alleys and many winding streets in a multitude of different lengths and widths. The intricately structured town needs luminaires which enhance its historical ambience. To ensure consistently attractive lighting, the different colours of the buildings had to be taken into account and the colour temperature and colour rendering index adjusted accordingly. It was essential that the light provided from these historical lanterns did not dazzle in residential areas, nor spoil the romantic atmosphere of candle-lit restaurants.
OSRAM has come up with an option that truly fits the bill with its prototype retrofit lamp that features Golden DRAGON® Plus LEDs. The light is fully directed to the exact place it is intended to illuminate whether it be directly onto the street of onto a building façade when it is used to highlight architectural features. Additionally, the desired level of luminance and the light distribution can be precisely adjusted by adapting the number of LEDs, the optical devices and the dimming level.
The LEDs have a colour temperature of 3500 K and a colour rendering index of 80. A common optical device combines the light from the individual LEDs into a single beam and accurately directs it towards the desired target. As part of this project, the alleyways known as “Blaue Liliengasse” and "Untere Bachgasse" were fitted with new luminaires and some of the LEDs were directed towards building façades. This demonstrates that the lighting can be precisely tailored to the architecture.
"The LED solution offered by OSRAM and Siemens is ideal: this modern lighting solution can be perfectly integrated in the historical centre and offers other advantages, too, such as energy savings, no light pollution and optimum façade illumination," said Alfons Swaczyna, Head Construction Manager and Director of the Civil Engineering Office of the municipality of Regensburg. He spoke of plans to convert most of the luminaires in the town centre to the new technology.
The prototype luminaire permits the replacement of ordinary 90 W mercury vapour lamps with LEDs. The luminaire design is based on a cylinder. Manufactured by the Regensburg branch of Siemens, the prototype can be fitted with different numbers of LEDs on either side as required in order to produce the desired lighting effect. Up to now, there was an uneven distribution of light, but now a homogenous illumination of around 3 Lux has been achieved.
"We have achieved the same luminance while cutting energy consumption from 90 W to just 42 W and additionally integrating façade illumination for historical buildings," said a contented Dr. Martin Moeck, Project Manager for Application Concepts at OSRAM Opto Semiconductors, "And there has also been a marked reduction in the direct glare."