Cooling That Won't Heat the Globe
The race speeds up to find substitutes for CFCs in refrigerators as ozone depletion accelerates
THE next time you open your refrigerator door for a midnight snack, pause a moment and say, "trichlorofluoromethane."Skip to next paragraph
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It may well be a homage to the past. Scientists and environmentalists from more than 80 countries meeting in Copenhagen two weeks ago agreed again to accelerate the phase-out of chlorofluorocarbons (CFCs).
These man-made chemicals in refrigerators, air conditioners, and cleaning solvents contribute to the depletion of the earth's ozone layer, which protects the earth from ultraviolet radiation.
The reason? According to scientists at the meeting, "ozone depletion is significantly worse than in 1990."
CFCs also contribute to the "greenhouse effect" in the lower atmosphere by trapping the sun's heat and other gases such as carbon dioxide. CFCs became popular because they are inert, cheap, and nontoxic.
But as a result of mounting evidence confirming ozone effects, President Bush accelerated a call for an end to the manufacture of CFCs in the United States by the end of 1995. Originally the deadline had been the year 2000. The 74 nations meeting in Copenhagen agreed to meet the same deadline as the United States.
In addition, a ban on the manufacture of halons, a chemical used in fire extinguishers, has been set for Jan. 1, 1994.
In 1892, trichlorofluoromethane became the first man-made CFC, a chemical that mixes chlorine, fluorine, and carbon. Without CFC and its subsequent chemical cousins, refrigerators and air conditioners would not have become the models of cold efficiency and durability that they are today.
FOR the past two years, scientists and corporations have been racing to find a replacement for CFC 12 in refrigerators as well as for a new kind of refrigerator insulation to replace urethane foam.
CFC 11 is used as a blowing agent to puff up the foam. Industry statistics indicate that 7.2 million refrigerators were manufactured last year.
"What appears to be a replacement for CFC 12 is HFC 134a," says Fred Hallett, vice president of industry and government relations for Frigidaire in Annapolis, Md.
Hydrofluorocarbons (HFCs) do not contain chlorine and are expected to break down in the atmosphere.
"We really don't know how persistent 134a will be [in the atmosphere]," he says, "and 134a does require special lubricants [in refrigerators or air conditioners]. We don't know what the performance will be over a long period of time when the two are together, but all the accelerated life tests we have done have indicated they will be satisfactory."
HFC 134a also has some toxicity problems, according to other experts, and it does trap solar heat, thus contributing to the greenhouse effect but not as significantly as CFCs.
According to the United States Environmental Protection Agency (EPA), tests with HFC 134a recently done on rats by an international consortium produced benign tumors.
But Drusilla Hufford of EPA says the tests used massive doses, far beyond anything that would be found in a home. "We think 134a will be safe to use," she concludes.
John Dieckman, manager of the Heating, Ventilating, Air Conditioning and Refrigeration Technology Unit at the consulting firm of Arthur D. Little in Cambridge, Mass., says, "Manufacturers of compressors for home refrigerators have been doing their homework in applying [HFC] 134a to existing compressors and getting favorable results. There is already a sizable production capacity coming on line for the fluid."