NHP Electrical Engineering Products has installed a PLC-based automatic control system to control the operation of high bay light fittings at their distribution facility in Laverton, Melbourne.
NHP’s Sustainability Centre located at their National Manufacturing and Distribution facility reflects a determined commitment to sustainable and renewable energy resources. This commitment has now been rolled out across the rest of this 12,000m² facility through the automatic light control project.
A key aim of the project was to reduce energy consumption of lighting in the eastern wing of the facility, which houses the distribution area. About 100 high bay light fittings accounted for most of the energy consumed in this particular wing of the facility. Each housing a 400W mercury vapour discharge lamp, the bay light fittings provide general lighting to the area during early-morning starts and late-night finishes, but are generally not required during the afternoon.
Using a suite of NHP products, the in-house team engineered a PLC-controlled automatic control system that measured the ambient light levels in the area and turned the high bays on and off as required. Some of the products used for the system included an Allen-Bradley MicroLogix 1400 PLC, PowerMonitor 1000 EM3 logging energy meter and a six-inch PanelView Component colour touchscreen HMI.
These components communicated with each other via an Allen-Bradley 5-port Stratix Ethernet switch, with Wago TopJob terminals utilised for wire termination and connection. Sprecher + Schuh CA8 miniature contactors took on the light switching duties utilising 24VDC coils while Wöhner fuse disconnects protected the voltage-sensing inputs of the energy meter. IME current transformers were used to measure the current being drawn by the light circuits.
The PLC program controls the timing of the high bays being turned on and off, giving them ample time to warm up and cool down. It also collects data from the energy meter, displaying details such as total energy consumed, current power demand and daily energy consumption on the touchscreen, and also allows ambient light levels to be trended showing light levels throughout the day.
According to David Cheng, NHP’s Development Engineer, the automatic light control system has reduced energy consumption by a pleasing 20%, with the daily average energy usage for lighting in the facility decreasing from approximately 715kWh to 565kWh in just three months of operation. He adds that this reduction in energy consumption will enable the system to pay for itself in less than two years.