Gatubelysning i Rednitzhembach

Rednitzhembach is a community located between the Nuremberg/ Fuerth conurbation and the lakes of Franconia. Over the last few years the existing infrastructure has been constantly upgraded. The street lighting, some of which was more than 25 years old, was modernised on the basis of a plan drawn up by N-ERGIE AG, the energy provider for the community. In this case, modernisation involved replacing the old high-pressure mercury lamps with modern high-pressure sodium lamps, in order to reduce energy consumption.
 

A brilliant future

N-ERGIE AG started by making an inventory of the street lighting. The luminaires were categorised according to whether or not they could be upgraded and whether they were already fitted with sodium light. Most of the 577 upgradable luminaires could be fitted with 50 W sodium lamps instead of 80 W mercury lamps. For Rednitzhembach this means that the community can save 77,000 kWh of electricity each year, which corresponds to around 10,000 euros. For the environment it also means a reduction in CO₂ emissions of 43,000 tons. The amortisation period at the time was around six years.

The rapid amortisation and short completion time were made possible by a unique solution from Tridonic. Conventional upgrades to a more efficient light source require the ballasts to be adapted and an ignitor to be installed. Instead, Tridonic offers an innovative concept that keeps upgrade costs and the volume of work to a minimum. Instead of completely redesigning the luminaires, all that’s needed is a single additional module.
 

A solution with energy-efficiency at its heart

This module tailors the existing ballasts to the requirements of high-pressure sodium lamps and supplies the ignition voltage needed to start the lamp. The existing ballasts remain in the luminaire. Upgrade costs are drastically reduced as a result. The terminal and luminaire wiring can be checked during the upgrade process for obvious damage and replaced if necessary. The energy savings are significant because of the greater efficiency of the high-pressure sodium lamp with its luminous efficacy of up to 150 lm/W compared with only 60 lm/W in the case of the high-pressure mercury vapour lamp. If, for example, a 125 W mercury vapour lamp is replaced by a 70 W sodium lamp, energy consumption will be 44 % less for the same amount of light. Thanks to these remarkable energy savings with sodium lamps and Tridonic ignitors with integrated supplementary impedance, overall investment costs are offset in only a short time.

Replacing high-pressure mercury vapour lamps with high-pressure sodium lamps and integrating Tridonic ignitors with supplementary impedance is an efficient way of keeping lighting systems up to date and operating them for the benefit of the environment and local budgets. The savings in energy and operating costs provide a strong argument for a complete upgrade. In most cases, the very short payback time for the upgrade offsets the investment costs within one budget period.
 

Projekt data
Ägare:	Rednitzhembach local authority, Nuremberg (D)
Strömförsörjningsbyrå:	N-ERGIE AG, Nuremberg (D)
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