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Sulfur Makes Efficient, Long-Lasting Light Bulb

October 21, 1994

WASHINGTON (AP) _ A new light bulb is being promoted by the Energy Department as a cheaper, more energy-efficient way to provide lighting in the 21st century.

The lighting system, under development by Fusion Lighting Inc., of Rockville, Md., uses sulfur particles that are bombarded by microwaves to produce a bright light that resembles sunlight, according to department officials.

Christine Ervin, the DOE’s assistant secretary for energy efficiency programs, called the new lighting technology very promising and said potentially it ″can save large amounts of energy and at the same time deliver more quantity and better quality light.″

The bulb is not yet being produced commercially.

Kent Kipling, vice president of Fusion Lighting, acknowledged ″a great deal of work still needs to be done″ to perfect the system for widespread uses. But he added ″the benefits of this new light source are just beginning to be realized.″

A prototype of the system recently was installed to illuminate the entryway of the Energy Department’s Forrestal headquarters building. Two of the new- technology bulbs, attached to the ends of a 240-foot-long, 10-inch-diameter reflector, provide enough light to replace 240 175-watt mercury lamps that previously lit the entry area, officials said.

The new lighting system cut energy consumption for the entryway area by 60 percent, the department said in a statement.

Development of the sulfur lamp began three years ago when technicians at Fusion Lighting, a small high-technology start-up company in a suburb of Washington, substituted sulfur for mercury in a bulb and discovered that when bombarded by microwaves it produced a bright, white light similar to sunlight.

Because the new bulb emits a relatively low-temperature light, the discovery meshed well with the a new lighting pipe design developed recently by a Vancouver, British Columbia, inventor, A.L. Whitehead, said DOE officials.

The combination produced the system used at the Energy Department headquarters and one that is expected to be ideal for a variety of outdoor or large, commercial uses, said Ervin.

The system is being developed with technical help from the Lawrence Berkeley Laboratory in California.

While a number of questions remain to be worked out, the new technology could lead to the use of cheaper, longer-lasting lighting systems in large commercial buildings as well as outdoors.

The Energy Department estimated that about 130 billion kilowatt hours of electricity are used annually to light large outdoor and indoor areas across the country at a cost of more than $8 billion a year.

″It will take time for this new technology to enter the market, but with such large numbers at stake, saving even a small amount is significant,″ the department said in a statement.

The system developed by Fusion Lighting uses a mixture of inert argon gas and a small amount of sulfur contained in a closed sphere about the size of a golf ball. The mixture is irradiated by microwaves from a compact generator similar to what is found in ordinary microwave ovens. The bright light is then directed down reflecting tubes to provide general lighting.

While the basic technology is proven, there remain questions as to long- term use. Unlike most high-intensity lighting, the sulfur bulb has no electrodes, which limit the life of conventional bulbs.

The Energy Department said that light from the new sulfur lamp closely simulates sunlight, that the light output appears not to diminish over time and that the ″life of the sulfur bulb itself is potentially limitless.″ At the same time, more tests will be needed to substantiate the expected commercial life of these bulbs, officials noted.

Fusion Lighting Inc., a privately held company, is a spinoff of Fusion Systems Corp., also of Rockville, a publicly held company that pioneered the use of microwave generators for producing ultraviolet light for various commercial purposes.