Bright future for energy efficient lighting

Get ready for new rules from the Dept. of Energy. Next year, DOE will implement regulations effectively making it impossible to equip some kinds of fluorescent lamps with transformer-style ballasts.

Light it up — International Rectifier devised this demonstration of a new CFL ballast chip for the device's European debut. In the U.S., Technical Consumer Products will make lamps incorporating the new chip under the Commercial Electric brand. Several makers of halogen light systems in Italy plan to use the halogen version of the ballast IC, says International Rectifier.

The DOE regs have energy consumption in mind. Lighting accounts for about 25% of all U.S. electrical power. No wonder, then, the DOE wants lamps to get more efficient. So its new regulations dictate what are called ballast efficacy ratings — basically a measure of energy efficiency. The ratings are such that transformer-style ballasts aren't efficient enough for many of the most common fluorescents used in shop and factory lighting.

The regulations apply mainly to longtube fluorescent lamps. They don't apply to low-power-factor ballasts as used in residential settings. Nevertheless, the handwriting is on the wall. Lamps of all kinds will have to be more efficient in the future.

This future is coming quickly in Europe. The EU will ban all magnetic ballasts in 2006, forcing a move to solidstate ballasts for fluorescent bulbs sold there.

Small wonder the emphasis on energy efficiency has fostered more interest in solid-state ballasts. These use switching circuitry instead of transformers to generate the high voltages (about 500 V) needed to initially energize fluorescent lights and the lower voltages used to sustain lamp operation. In so doing they can provide energy efficiency by controlling the lamp waveform more precisely. One drawback to the electronic approach, however, has been higher cost.

Recent developments indicate that the cost differential may soon be a thing of the past. International Rectifier, a maker of integrated circuits with U.S. offices in El Segundo, Calif., recently developed a chip designed specifically to handle ballast functions for compact fluorescent (CFL) bulbs. (The term CFL applies to families of smaller-diameter fluorescent lamps designed as replacements for incandescent bulbs.)

Though energy efficiency was one motivation for IR's new chips, ballasts using the ICs will also be more reliable, space efficient, and cost less than older solid-state devices. The company has also devised new ICs targeting ballasts for halogen lights. And high-intensity discharge (HID) lamps may eventually get ballast ICs using similar technology, say IR officials

INSIDE A LAMP
Fluorescent lamps consist of a tube filled with inert gas and a small amount of mercury vapor. The ballast energizes the gas by applying a high voltage to heat the filaments. Once the mercury starts to conduct, 200 V or less is enough to maintain it. When the lamp is on, the ballast also serves as a current limiter.

The mercury produces most of its energy in the ultraviolet (UV) range. The UV activates a white phosphor coating on the tube, which then emits visible light. Fluorescents are physically larger than incandescents of the same light output because it takes more surface area to emit an equivalent amount of light. Fluorescents are more efficient, however. Incandescent bulbs produce about 15 lumens/W, Energy Star-qualified CFLs, 40 to 60 lumens/W.