Prismatron saves energy for Schneider Electric

Lighting of a recent extension to the Schneider Electric Warehouse and Distribution Centre is using using Holophane's new Prismatron system to provide dimming of 400W ceramic metal halide lamps in response to daylight levels and occupancy. The Prismatron system is made up of prismatic glass high bay luminaires and a special electronic dimming ballast.

The new building provides warehousing facilities, as well as an assembly area for control panels, and the roof incorporates skylights to allow natural daylight into the space. "We opted for Prismatron because it enables us to make savings by using dimmable lighting in areas that are not used very often and at times of day when the lighting does not need to be at full output," explained Schneider's Mike Biggs.

The system, installed by Kendall Electric, uses 308 Prismatron luminaires connected in pairs to Prismatron remote dimmable ballasts. The luminaires are suspended directly from a bus bar carrying 230V mains power and integral low voltage control signals.

The warehouse area is divided into four quadrants for the purposes of lighting control, with a lux sensor in each quadrant, used to maintain an illuminance of 280-300 lux. The assembly area for control panels is divided into two sections, each with a lux sensor, maintaining illuminance levels at 400 lux.

Each of the lux sensors produces a 0-10V control signal in direct proportion to the lux levels, sending the signal to a Schneider PLC building controller, which in turn communicates with the Prismatron dimmable ballasts. In this way, the lamps are dimmed or ramped up in direct relation to the lighting requirements of the space.

In the aisles between racking, occupancy detectors are also used in conjunction with the dimming system, reducing the lamps to 25% of their full output when no presence has been detected in the area for 10 minutes. As soon as someone walks into the aisle the lamps are increased to 100% output immediately. Again, this control is achieved through the Schneider building controller.

At the Schneider warehouse the Prismatron system is used with GE CMH 400W ceramic metal halide lamps, which provide higher efficiencies and better lumen maintenance than conventional metal halide light sources. The lamps also provide better colour rendering, with a CRI of over 90, as well as improved colour stability through the life of the lamp.

This combination of high efficiency lamps and the Prismatron dimmable system provides Scheider with significant savings in cost of ownership. Not only is energy consumption reduced but maintenance costs are also less because re-lamping cycles are extended.