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UM enters miracle icebox in ozone offensive


A team of Maryland engineers has found a way to replace the ozone-depleting chemicals in your household refrigerator, keep your fruit and vegetables fresher and slash your electric bill.

Don't rush to the nearest appliance store in search of these miracle iceboxes, however.

The U.S. Environmental Protection Agency says the University of Maryland College Park has made an important advance in the search for substitutes for chlorofluorocarbons, the widely used family of chemicals blamed for eating a hole in Earth's ozone layer.

"This technology will not only help protect our stratospheric ozone layer, but will demonstrate that preventing pollution can be profitable," EPA Administrator William K. Reilly said in a statement yesterday.

Appliance manufacturers are more cautious. They say the technology is still unproven, though promising.

The new technology, which involves tinkering with the air-cooling system of refrigerators, shows that replacing the liquid CFCs now used in all freezers and fridges can save energy and electricity costs, said Dr. Reinhard Radermacher, associate professor of mechanical engineering, who oversaw the research project.

Tests run with modified refrigerators using a variety of different CFC replacements yielded energy savings of 8 percent to 16 percent, say EPA officials.

That means consumers could knock $100 to $200 off their electric bills over the 18-year life of an average-sized 18-cubic-foot appliance.

If it were used in all the nearly 8 million refrigerators and freezers sold every year, EPA officials add, the new design could result in energy savings equal to three-fourths of the cost of phasing out CFC production in the United States.

The Bush administration pledged to achieve the phase-out by the end of 1995 in the wake of findings that the ozone layer is thinning faster than previously thought.

Dr. Radermacher's research team, supported by a $350,000 EPA grant, modified existing refrigerators by changing their air-flow systems.

CFCs in today's refrigerators are pumped through an evaporator, which chills the air inside the freezer section enough to make ice cubes. That air is then blown by fans into the fresh-food section to cool the food stored there, and back up to the freezer again to be re-cooled.

The engineers replaced that system with two independent evaporators, one each for the freezer and fresh-food sections. Energy is saved because the liquid refrigerant, which absorbs heat from the air inside a refrigerator by boiling, does not have to chill the air in the fresh-food section as much as it does in the freezer.

The new refrigerators also will keep fruits and vegetables from drying out as quickly, because air inside the freezer and in the fresh-food section is chilled separately. That separation also will keep ice cubes from picking up aromas of food.

The idea being worked on originated in 1975 in what was then East Germany, said Dr. Radermacher, who is also director of UM's new Center for Environmental Energy Engineering. Several other researchers have tried without success to duplicate the 20 percent energy savings reported then, he said. The UM team's three-year effort is the first to approach it.

"We had the time and the funds to pursue the project further than some of the others," Dr. Radermacher said.

Dr. Radermacher would not reveal what refrigerants he tested to replace CFCs, saying he was awaiting approval of a patent for some of them.

John S. Hoffman, director of EPA's global change division, said the mixtures of chemicals tested contained some chlorine, the element responsible for destroying upper atmospheric ozone, but they have far less than CFC 12, the chlorofluorocarbon now in use.

Bob Johnson, who is in charge of finding CFC replacements for Whirlpool Corp., a leading refrigerator and freezer manufacturer, says the Maryland study is "good sound research" that could produce "very significant" energy savings for consumers, if it proves commercially viable.

A big unknown is how much the modifications might add to the typical new refrigerator's $500 price-tag.

Whirlpool assisted the UM research, but Mr. Johnson cautioned that his company and others in the industry were looking at a variety of changes in refrigerator design and coolant mixture to comply with the CFC phaseout and with federal energy efficiency standards.

EPA officials, though, say they believe this is one of the most promising studies they have seen to date.

"There are other technologies out there that may be better," Mr. Hoffman said, "But this puts a stake in the ground that will have to be beaten."


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