CityU researchers develop energy-saving device for electric lighting systems

Two City University (CityU) researchers have developed central dimming technology for lighting systems that can reduce electricity consumption.

In electric lighting systems such as fluorescent lamps, a device known as a ballast is used to control and limit the electric current passing into the lamp.

Current electronic ballasts can help reduce electricity consumption by between 10 to 15 per cent compared to traditional electronic ballasts. But electronic ballasts don't last long and can only control two lamps at most, thus leading to accumulation of toxic electronic waste.

Ron Hui and Henry Chung, from CityU's Department of Electronic Engineering, have developed a central dimming technology that can turn non-dimmable electromagnetic ballasts into dimmable ones, which helps to save energy.

Each central dimming system can control up to 200 lamps, resulting in a substantial reduction in electronic waste.

Testing for the system started in September last year in the mainland, showing an average electricity savings of 30 per cent. It is being installed to control more than 5,000 street lamps.