New Light Bulb Offers Energy Efficiency

Paul Malamud

Washington-A newly-invented light bulb could offer significant energy savings-and better light-to future users worldwide,according to the U.S.Department of Energy.

on october 20 the U.S. Department of Energy(DOE) announced it was"inaugurating the use"of the new kind of light bulb in experimental installations at its Forrestal Headquarters Buildingand at the Smithsonian's National Air and Space Museum in Washington,D.C.

The new lighting technology,DOE said in a written statement, is most likely to take the form of"high quality,high-efficiency illumination for large indoor or outdoor spaces" once it is madecommercially available.

The new kind of artificial light consists of a bulb filled with inert gas and a small amount of sulfur that is bombarded by microwaves to produce luminescence The Washingon Postwrote, ".One golf-ball-sized sulfur bulb,when irradiated by the kind of compact microwave

generatorfound in ordinary kitchen ovens,puts out as much light as hundreds of high-intensity mercuryvapor lamps."

A small microwave generator at the base of the bulb bombards the inert gas,heating it.Thehot gas energizes electrons in the sulfur, which then emit a large amount of visible light.Thebulb itself is rotated quickly by a motor to coolit-otherwise it would melt.

Christine Ervin, an official at DOE, called the technology "advanced and promising," noting "itcan save large amounts of energy and at the same time deliver more quantity and betterquality light." She added the technology could improve lighting of public spaces while

benefiting"the economy and the environment."

After the new lighting arrays were installed in the Forrestal Building, they reduced energy usage"by more than 60 percent" for that area,Ervin said.DOE estimates that the cost of lightinglarge areas in the United States is 8,000 million a year,so if the new bulb is widely

used,sayings could be significant.

According to DOE, the new lighting has attractive optical qualities, "closelysimulating sunlight."

In current test arrays,two small bulbs are put into each end of a 72-meter-long reflective plastic "light pipe." One of these pipes now lights an area that had been lit by 240 175-wattmercury lamps in the Forrestal Building,producing four times as much light at one third

the cost.

Experts note the "new-fangled" bulb emits less ultraviolet light than traditional large-arealighting，making it easier to avoid damaging displays or works of art. In addition, the new kindof light,which is optically somewhat similar to sunlight, seems to be good for growing plants.

At the moment,nobody knows howlong the new bulbs willlast. Since they do not have electrodes there are no filaments to burn out-so they may last a long time.Light output doesn't seem to diminish after extensive use and since this high-efficiency lamp does not make

use of mercury,there is no toxic mercury to dispose of.