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Chlorofluorocarbons (CFCs)hemical compounds called chloro-c,uorocarbons (CFCs), which aredely used today, have been linkedo environmental problems that

depletion and global warming.new federal law- itleVIof theean Air Act Amendments of 1990as been passed to reduce produc-on of CFCs, leading to a total phase-2000.Specificies to reduce CFC emissionsnclude recycling, reclamation,andecovery of CFCs; early detection ofefrigerant leaks and modification ofand useof alterna-ve compounds to replace CFCs.

Hotline 1-800-872-3568 _ _ _ _R A D M N STRAT ION

History of CFCsChlorofluorocarbons (CFCs) are chemical compounds made of chlo-rine, fluorine, and carbon. One member of the CFC family, calledaha-lon, also contains bromine.CFCs were originally invented in the 1930s for the refrigerator marketto replace the other common refrigerants, such as ammonia, carbon di-oxide, ethyl chloride, isobutane, methyl chloride, and sulfur dioxide.Many of these coolants were flammable, toxic, or both. The new CFCswere hailedasthe perfect compounds, because they are nontoxic, non-flammable, noncorrosive, and extremely stable. Furthermore, theyhave excellent thermodynamic properties and never wear out.CFCs are primarily used asrefrigerants and solvents. Among the mostuseful chemicals ever invented, CFCs are found in many aspects ofmodern living. They are used to refrigerate food and drugs; coolhomes, buildings, and cars; clean electronic components; insulate build-ings and refrigerators; and create packaging. Halons are used as pro-pellants in fire extinguishers. Products using CFCs account for $135billion worth of products in the United States.Ozone Deplet ion TheoryIn the early 1970s, scientists discovered that CFCs were accumulatingin the stratosphere, 7 to28miles above the earth, and destroying theozone layer. The ozone layer absorbs and scatters ultraviolet rays fromthe sun, protecting the earth from excessive exposure to their harmfuleffects.A decrease in the ozone layer is suspected to have negative bio-logical effects, including increased incidence of skin cancer and eyecataracts. The Environmental Protection Agency (EPA) estimates thateach1percent depletion in stratospheric ozone could lead toa2per-cent increase in skin cancers among fair-skinned people.When CFCs and halons are released into the atmosphere they eventu-ally reach the upper stratosphere. There they are broken down by ultra-violet radiation, releasing free chlorine or bromine atoms, whichdestroy the ozone. Each free chlorine atom is thought to be capable ofdestroyingupto 100,000ozone molecules. Bromine is considered evenmore harmful than chlorine; however, because halons are released in

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lower quantities than other CFCs,they account for less than 10per-cent of the stratospheric ozonedestruction. CFCs have long at-mospheric lives of 40 to 380 years.Ozone DepletionPotent iaINot all CFCs damage ozone tothe same extent.A measure re-ferred to as ozone depletion po-tential (ODP) describes theparticular CFC compounds abil-ity to destroy protective ozone.The ODP for a compound repre-sents its destructive ability com-pared to that of CFC-11 andCFC-12, which haveabaselinevalue of one. The larger the ODPvalue, the greater the ozone deple-tion potential. The ODPs for com-monly-used compounds areshown in the table.It is important to understand thedifferences between the variouscompounds: CFCs, HCFCs, andHFCs.A simple hydrocarbonmolecule is the basic structurefrom which all three are derived.CFCs are fully-halogenated hy-drocarbon molecules in which allthe hydrogen atoms have been re-placed with chlorine or fluorineatoms. CFCs are considered tocause the most ozone depletion; itis theorized that the high ODPsare due to chlorine. Examples offully-halogenated CFCs are CFC-and CFC-115.HCFCs, or h ydrofluorocarbons,are hydrocarbon molecules inwhich some, but not all, of the hy-drogen atoms have been replacedwith bromine, chlorine, or fluo-rine atoms. HCFCs are less harm-ful to the ozone because most ofthe molecules break down at ele-vations below the ozone layer.These compounds have much

11,CFC-12, CFC-113, CFC-114,

shorter atmospheric lifetimesthan CFCs and only 2 to 5 percentof the ozone depletion potential.They are generally used in equip-ment such as residential, window,and commercial rooftop air-condi-tioning systems and heat pumps.HFCs, or hydrofluorocarbons, arecompounds being developed toreplace CFCs. These compoundscontain no chlorine to harm theozone layer. Some problems withHFCs include failure to pass long-term toxicity tests, lack of effec-tive lubricants, and lack ofproduction-level manufacturingtechniques.HFC-134a would bealikely sub-stitute for CFC-12. This refri-gerant will be used in domesticrefrigerators and automobileair-conditioning systems. Mostmanufacturers have solved thelubricant problem by usingester-based lubricants orpolyalkylene glycols.Global Warm ing PotentialNot long after their effect on theozone layer was discovered, scien-tists discovered that CFCs werealso contributing to the green-house effect. The greenhouseeffect results when infrared radia-tion emitted from the earth istrapped by the atmosphere, caus-ing the earths climate to increasein temperature. The greenhouseeffect is caused by certain gasesthat collect in the atmosphere andradiate the earths infrared energyback to the earth. The followinggases contribute to this effect:carbon dioxide, methane, nitrousoxide, and CFCs.The most abundant of the green-housegasesis carbon dioxide. Al-though CFCs are not as abundantas carbon dioxide, pound forpound they are thousands oftimes as potent as carbon dioxide

in causing global warming be-cause CFCs are more efficient inabsorbing infrared radiation.Studies indicate that CFCs ac-count for about one-fifth of theglobal warming effect.The greenhouse effect of aparticu-global warming potential (GWP).The GWP of each compound isrelative to that of CFC-11, whichhasavalue of 1O. The larger theGWP, the greater the contributionto the greenhouse effect. TheGWPs for commonly-used refrig-erants are shown in the table.

lar compound is expressed as its

Govern m en Regu a o nof CFCsIn 1978, theFoodand Drug Ad-ministration banned the use ofCFCs as aerosol propellants in allbut a few essential applications.As a resuIt, the use of CFCs inaerosol propellants was reducedby 95 percent. However, evenwith this ban, between 1978 and1985, the global levels of strato-spheric ozone dropped an aver-ageof 2.5 percent.In 1987,36 countries, includingthe United States, signedatreatythat seeks to protect the strato-spheric ozone layer. This treaty,commonly known as the Mont-real Protocol, calls for stepwisereductions of CFC and halonproduction over the next decade,ending in atotal phase-out by theyear 2000. The second MontrealProtocol, afollow-up agreement,was signed in London in June1990 by 93 countries. It expandsthe treatys scope to other ozone-depleting chemicals, suchascarb-on tetrachloride and methylchloroform, which will be phased-out by the years 2000 and 2005,respectively.

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Electric Ideas Clearinghouse is acomprehensive information sourceand industrial en-ergy users. I t is operated by theWashington State Energy Officend is part of the Electric Ideastechnology transfer program spon-sored by participating utilities andthe Bonneville Powerdministration.Bon nevi1ePower Administration,the state of Washington, the Wash-ington State Energy Office, norny of their contractors, subcon-tractors, or their employees make

y warranty, expressed or im-ied, or assume any legal respon-li ty for the accuracy,ess, or usefulness of anynorma t on, apparatus, product,ocess disclosed within thisblica tion.

either the United States nor the

Technology UpdateCH -9ol l-, -e Hotline:-800-872-3568ax: 1-800-872-3882lect ronic Bullet in Board:-800-762-3319

The Futu re for CFCsAs restrictions become enacted into law, reduction strategies will be-come much more prevalent. Because of decreasing supply and increas-ing tax, the price of refrigerants will rise, creating an economicincentive for reducing their use. Chemical companies are now workingon potential replacements for ozone-destroying CFCs. Air-condition-ing and refrigeration manufacturers must redesign equipment to ac-commodate new refrigerants. It will cost the U.S. economy billions ofdollars to make the transition to safer refrigerants. However, the time,effort, and money spent on this transition will help to secure humanhealth and environmental soundness for future generations.Bibl iographyASHRAE.1989ASH RAE Handbookof Fundamentals. 1989.ASHRAE.Reducing Emission of Fully Halogenated Chlovofluorocarbon (CFC)Re-frigerants in Refrigeration and Air-conditioning Equipment and Applications.Guideline ANSI/ASHRAE 3-1990.Atwood, T. CFCs in Transition. CFCs: Timeof Transition.ASHRAE. Pp. 60-65. 1989.Cale, P.S. andK. H.Heiting. The Wonder Chemicals Must Go. Iowa EnergyBulletin.Volume 16,No. 1. owa Department of Natural Resources.January/February 1991.Clarke, E.M.,G. G.Anderson,W. D. Wells, and R.L. Bates. Retrofitting Exist-ing Chillers with Alternative Refrigerants.ASHRAE J ournal.Pp. 41. April1991.Denny, R.J. The CFC Footprint. CFCs: Timeof Transition. ASHRAE. Pp. 23-28. 1989.Fischer,S. Energy Use Impact of CFC Alternatives. Energy Engineering. Vol-ume 88, No.3, Pp. 8.1991.Frank, A. L. CFC, Halon Phaseouts Set for 2000 in Protocol Signed by 93Countries. Energyand Housing Report. ALFA Publishing. June 1990.Gilkey, H.T. The Coming Refrigerant Shortage.HeatinglPipinglAir Condition-ing.Pp. 41-46. April 1991.McLinden, M.O. and D.A. Didion. Quest for Alternatives.CFCs: TimeofTransition.ASHRAE. Pp. 69-78. 1989.Miller, R.Refrigeration andAivConditioning Technology.Peoria, Illinois: Bennett&McKnight Publishing Company. 1983.Moore, T. Global Response to CFC Refrigerants.EPRI J ournal.September1989.Other SourcesRefrigeration Service Engineers Society1666Rand Rd.Des Plaines, IL 60016-3552

DOE/BP-39833-17December 1991I S M

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