Sustainable Lighting Technology: From Devices to Systems

With the recent revolution of LED technology, new LED devices with much improved luminous efficiency and  lifetime are now commercially available. They are also expected to replace energy-inefficient incandescent lamps and mercury-based fluorescent lamps in the future. LED technology actually involves several technical aspects, including (i) LED Devices, (ii) LED Drivers, (iii) Power Control and (iv) Thermal Design of Lighting Fixtures.

While LED technology has successfully found applications in decorative, signaling, display and signage applications, it is still not widespread in public lighting applications. With continuous progress in LED “devices”, recent creditable research highlights the actual bottlenecks of LED technology in public lighting lie in the “system” aspects.

The lifetime of an LED “system”, for example, is limited not by the lifetime of the LED “devices” (typically 80,000 hours), but by the lifetime of the electrolytic capacitors (typically 8,000 hours) in conventional LED drivers.

This proposal is related to the “sustainability” of lighting systems (used in buildings and cities’ large-scale infrastructures such as road lighting) that consume 20% of electricity globally.

Sustainable Lighting Technology proposed here deviates from the traditional Energy-Star concept which focuses only on energy saving. It stresses a new principle that includes (i) energy saving, (ii) long product lifetime and (iii) recyclability of product materials.

It highlights the important point that “energy-saving technology is not necessarily environmentally-friendly if it generates lots of harmful electronic waste within a short product lifetime.