Energy Efficiency & Environmental News: CFC Replacements 1

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1 September 1993 Energy Efficiency & Environmental News: CFC Replacements 1 Florida Energy Extension Service and Mike West 2 CFC REPLACEMENTS: KEEPING YOUR COOL AND THE OZONE LAYER As most everyone has heard, atmospheric ozone protects life on Earth from the harmful ultraviolet radiation emitted by the sun. Emission of chlorofluorocarbons (CFCs) leads to depletion of this protective ozone layer. CFCs also contribute to global warming. The connection between CFCs, stratospheric ozone depletion, and the increased incidence of skin cancer is scientifically accepted. Halons, used mainly in fire extinguishers, may also deplete the ozone layer. CFCs are used in air conditioning and refrigeration equipment, insulators, solvents, and foams. CFC-12 is used mostly in automobile air conditioners, window air conditioners, and refrigerators. Most residential and building air conditioning systems use less harmful HCFC-22. Even if all CFCs were eliminated today, their effect on the ozone layer would not disappear until the year 2050 due to their long residence time. The 1987 Montreal Protocol designed to slow the depletion of atmospheric ozone initiated what has become a concerted effort to reduce widespread use of CFCs as refrigerants. The protocol defined a list of ozone harmful substances and created a timetable for reduction and eventual cessation of their use. The effort is supported by further international agreements in London and Copenhagen. In the United States, this effort first appeared as federal law in the 1990 Clean Air Act. As of May 15, 1993 products containing CFCs, and most products that use CFCs in their manufacture, must have a warning label that informs consumers that CFCs harm public health and the environment. For example, new cars must display a window sticker stating the presence of CFCs. The probable impact on consumer purchasing has motivated manufacturers to switch to ozone safe alternatives. The 1990 Act will be amended to include the Copenhagen agreement which calls for a reduction of CFC production to 25 percent of 1986 levels by January CFC production in the U.S. will stop by January HCFC-22 production will be reduced to 65% of 1989 levels by 2004 with a production ban by At the 1992 International CFC and Halon Alternative Conference, held in Washington, D.C., most of the industry representatives in attendance agreed that these targets will be met. The EPA expects immediate CFC-12 shortages by In addition, the federal government is imposing increasing taxes on CFCs and high fines for the release of CFCs into the atmosphere. For example, the fine for charging (filling) an AC system with a known leak is $25,000, and a $10,000 reward is offered for information leading to a conviction. In the past four years, the decreased supply and increased taxes and liability has doubled the price of CFC-12 from about $4 per pound in 1989 to about $8 per pound today. Taxes will increase from $1.67 per pound in 1992 to $5.35 per pound in Prices are expected to continue rising. (A typical auto AC system contains about three pounds.) Leaks account for 41% of all lost refrigerant. So, ozone safe alternatives are now economically, as well as environmentally attractive. 1. This document is the September 1993 issue of Energy Efficiency and Environmental News, the newsletter of the Florida Energy Extension Service, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication date: September Florida Energy Extension Service, University of Florida, P.O. Box , Gainesville, FL ; Mike West, Extension Specialist in Mechanical Engineering, Center for Biomass and Energy Extension, P.O. Box , Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL The Florida Energy Extension Service receives funding from the Florida Energy Office, Department of Community Affairs and is operated by the University of Florida s Institute of Food and Agricultural Sciences through the Cooperative Extension Service. The information contained herein is the product of the Florida Energy Extension Service and does not necessarily reflect the views of the Florida Energy Office. Mention of a manufacturer or tradename does not constitute an endorsement.

2 Energy Efficiency & Environmental News: CFC Replacements Page 2 To date, a number of new ways of doing business are evident. For example, Ford Motor Company s Lincoln Mark VIII and Limited Edition Taurus use ozone safe HFC-134a in place of CFC-12. Currently, only certified AC mechanics can purchase CFC-12. All AC technicians must be certified by Supermarket coolers have been retrofitted for HFC-134a by changing a few small components and seals, and switching the lubricant. Many industrial chillers are now using HCFC- 22 as a "transition refrigerant." HCFC-22 has long been used in residential AC equipment. HCFC-22 is less harmful to the ozone layer, but will be slowly phased out in preparation for a production ban in Currently, research is underway to develop even safer refrigerants and refrigeration equipment. New refrigeration technologies based on acoustic compressors or Stirling cycles, which use inert gases such as nitrogen, are being developed. Another promising product is the desiccant air conditioning system which is entirely refrigerant free. Desiccant equipment uses heat from a conditioning system which is entirely refrigerant free. Desiccant equipment uses heat from solar collectors or natural gas to pull moisture from the air. This very dry air is then chilled using evaporatively-cooled water. Currently, FEES is participating in a demonstration of a desiccant air conditioner at the KFC restaurant in downtown St. Petersburg. Gel refrigerants, which do not escape into the atmosphere, have been developed and may be cost effective by the end of this decade. Consumers are encouraged to select CFC-free products. If there are no leaks, removing CFCs from refrigerators or AC systems is not necessary. Prompt attention to leaking equipment will limit the amount of CFC gas that escapes. Over the next two years, as CFC refrigerants become unavailable or prohibitively expensive, it may be necessary to either purchase new appliances or have the equipment retrofitted with an ozone safe replacement refrigerant. Already, ozone safe alternatives are available at competitive prices. For example, Dupont sells HFC-134a at about the same price as CFC-12. Servicemen and mechanics are required to collect "used" CFC refrigerants, and most can recycle them in-house. Refrigerants do not wear out, they just become contaminated. Recycling consists mainly of removing contaminants such as air, oil, water, and metal particles. the unit due to the higher evaporator temperature. To preserve cooling capacity and energy efficiency, it is recommended that retrofits be avoided unless there is a leak. Although no performance reports are available yet, Dupont claims their MP-39 refrigerant provides comparable performance to CFC-12. Most manufacturers agree that while retrofiting a CFC-12 system with HFC-134a will reduce performance, systems designed for HFC-134a can be more efficient. Ozone Friendly CFC Alternatives After many years of investigation and testing, two refrigerants have emerged as the current industry choice for replacement of CFC-12 (dichlorodifluoromethane CCl 2 F 2 ). They are HFC-134a (tetrafluoroethane CHF 2 CHF 2 ), and MP-39 which is a blend of HCFC-22 (Chlorodi-fluoromethane CHClF 2 ), HFC-152a (DifluoroethaneCH 3 CHF 2 ), and HCFC-124 (Chlorotetrafluoroethane CHClFCF 3 ). Although less harmful than CFC-12, the HCFCs in MP-39 do have a measurable effect on ozone and are expected to be phased out by the year HFCs, which contain no chlorine and thus have 0.0 ODP (Ozone Depletion Potential), are more promising. In comparison, CFC-12 has an ODP of 1.0, and HFC-22 has an ODP of Unfortunately, the ability of HFCs to absorb infrared radiation as a greenhouse gas makes their future acceptability uncertain. HFC-134a, HFC-152a, and HCFC-22 have a GWP (Global Warming Potential) of less than one, as compared with a GWP of 3.0 for CFC- 12. While HFC-134a appears to be the most environmentally friendly alternative for newly manufactured equipment, MP-39 is more attractive as a replacement for CFC-12 in existing systems. A direct switch to HFC-134a in a system designed for CFC-12 will result in about a 10 percent decrease in refrigeration capacity. This will cause an increase in energy consumption due to the longer run time that will be needed to satisfy the cooling load. The system will be about 4-10 percent less efficient when retrofitted with R- 134a, causing a corresponding increase in greenhouse gas emissions at the power plant. Although no published performance data is available yet, manufacturers claim that MP-39 delivers the rated cooling capacity and efficiency in a system designed for CFC-12. In contrast, new equipment designed for use with HFC-134a can be more efficient than their CFC-12 counterparts. EES Tests R-134A as a "Drop-In" Retrofit A 12,000 Btuh air conditioner, designed for use with CFC-12, was switched to HFC-134a. The purpose of the test was to evaluate the difficulty of carrying out the refrigerant retrofit procedure, and to compare the performance of the two refrigerants.

3 Energy Efficiency & Environmental News: CFC Replacements Page 3 First, the baseline performance of the unit was measured using CFC-12. It provided 12,730 Btuh of cooling capacity and drew 954 Watts of electrical power, giving an EER (Energy Efficiency Ratio) of The maximum system refrigerant pressure was 142 psig and the maximum temperature was 162 F. The evaporator temperature was 44 F with a superheat of 8.4 F. To carry out the replacement, the CFC-12 was first discharged into a storage tank. Then, the mineral based lubricating oil was drained from the system and replaced with Castrol Icematic polyol ester lubricant. The amount of oil drained was carefully measured to determine the concentration of mineral oil remaining. The system was recharged with CFC-12, run for 20 minutes, discharged, and drained of oil again. After a second fill with the ester oil, it was determined that the concentration of remaining mineral oil was below the manufacturer s recommendation of 4 percent. The unit was then charged with HFC-134a using standard equipment and procedures. The existing filter drier was compatible. No other changes were made. The performance of the unit using HFC-134a was then measured. It provided 11,040 Btuh of cooling capacity (a decrease of 13%) and drew 953 Watts (no significant change), for an EER of The maximum system refrigerant pressure was 157 psig and the maximum temperature was 158 F. The evaporator temperature was 47 F with a superheat of 6.4 F. Replacement of CFC-12 with HFC-134a in this system was completed with little difficulty. Other systems may require additional changes. While the power draw of the unit remained unchanged, the decrease in capacity means that the unit must run longer with HFC-134a to provide the same degree of cooling that CFC-12 does. HFC-134a also slightly reduced the dehumidification capacity of Using Ozone Friendly Refrigerants Questions concerning the compatibility of the ozone friendly refrigerants with equipment designed for CFC- 12 must, of course, be evaluated on a case-by-case basis. In general, the evaluation involves the compressor, the condenser, the expansion device, the lubricating oil, and the filter/drier. Compressor: HFC-134a requires a lower refrigerant flow rate but a higher compressor discharge pressure. This results in decreased cooling capacity since the condenser temperature is not high enough to adequately transfer heat away from the system. Some compressors may require new gaskets and seals if the originals are not compatible; the cost for this change is around $200 for an automobile AC system. MP-39 doesn t require changes. Condenser: In an HFC-134a retrofit, a larger condenser can provide additional subcooling and restore some or all of the cooling capacity. If a compressor designed for HFC-134a is used with the original CFC-12 condenser, the condenser must be able to withstand an additional pressure of 12 to 50 psi or more. MP-39 doesn t require condenser changes. Expansion Device: Since the refrigerant flow rate is lower and the superheat properties of HFC-134a are similar to that of CFC-12, it may be possible to use the existing Expansion Valve. Superheating will be about 2 F less. Although no published data is available yet, CFC-12 capillary tubes and orifices may result in elevated evaporator temperature and compressor slugging if used with HFC-134a. MP-39 is compatible with CFC-12 expansion devices. Lubricating Oil: Both MP-39 and HFC-134a are not miscible with the standard mineral oil typically used in CFC-12 equipment and require the use of synthetic lubricants. MP-39 requires an alkylbenzene based lubricant such as Nu-Calgon s Zerol. HFC-134a requires a polyol ester lubricant such as Castrol s Icematic. These lubricants are significantly more expensive than mineral oil, but offer better performance and can increase system efficiency. Filter/Drier: Replacement of the filter/drier is recommended, particularly when using HFC-134a since polyol ester oils are 100 times more hygroscopic than mineral oils and they hydrolyze to form acids. The XH-7 and XH-9 solid-core molecular sieve driers are recommended. MP-39 is not compatible with the XH-5 and XH-6 loose fill desiccant. Solid core driers made with bauxite are not recommended for use with HFC-134a since the polyol ester oil is absorbed with water promoting the formation of acids. A Third CFC Replacement Enters the Market OZ Technology, Inc. (Post Falls, Idaho) is marketing a hydrocarbon based CFC-12 "drop-in" replacement amid some concern over the flammability of the proprietary mixture. Flammability tests by the company have concluded that the danger of combustion is extremely

4 Energy Efficiency & Environmental News: CFC Replacements Page 4 small, and the danger is considerably less than the danger posed by gasoline fuel. The product contains an odor additive, similar to that used in natural gas, for early leak detection. Test results provided by the manufacturer state an increase in refrigeration efficiency of 18% and full compatibility with CFC-12 in any percentage. Independent test data are not yet available. OZ-12 has been submitted to the EPA for approval, but since it is not considered hazardous (unless considered ignitable) there are currently no restrictions on its sale or use. The temperature required to ignite OZ-12 is 735 F and it will burn in low concentrations (98.1 to 91.5% air). In comparison, the ignition temperature of HFC-134a is 1380 F in greater concentrations (60% air). Propane, which has similar flammability limits to OZ-12, is used as a refrigerant in some European countries. The ultimate decision as to the safety of OZ-12 will be left to the consumer. References "Alternative refrigerants and energy savings in supermarkets," Advani, Atma. ASHRAE Journal, V.34, Dec 1992, p "Heading for zero R; alternatives to CFCs and halons," Newman, Alan. Environmental Science and Technology, V.26, Dec 1992, p "Refrigerants of the future: facts and fallacies," Atwood, Theodore. ASHRAE Journal, V.33, Feb 1991, p "Energy Use Impact of CFC Alternatives," Fischer, Steve. Energy Engineering, V.88, no.3, p Dupont Technical Bulletin ART-5 and ARTD-10. Nu Calgon Product Bulletin 3-69 Castrol Technical Bullettin No. 2 "CFC replacement in industrial refrigeration systems." NREC Newsletter, V.7, issue 2, Spring p.1-4. DID YOU KNOW......that the U.S. Senate s proposed 4.3 cent-per-gallon gas tax increase means at most $25.80 per year to the average driver (12,000 miles at 20 mpg). The extra cost can easily be canceled out with a 3.5% increase in mpg, say from 28 to 29 mpg. This is easily done by avoiding quick starts and keeping tires properly inflated....that of the 8.3% of U.S. energy that comes from renewable sources, 50% comes from biomass, 45% is hydroelectric, and 5% is geothermal, wind or direct "The CFC issue: refrigerant substitutes." Journal of the IES, V.35, Sep/Oct 1992, p.15+. "Refrigerants for an ozone safe world," Moore, Taylor. EPRI Journal. V.17, Jul/Aug 1992, p "EPA Identifies new alternative refrigerants." ASHRAE Journal, V.34, Jun 1992, p.6. "Alternative refrigerants: challenges, opportunities," Calm, James M. Heating, Piping, and Air Conditioning, V.64, May p "EPA s research projects relating to the dual-circuit and Lorenz refrigerator/freezers," Bare, Jane C. Journal of the Air and Waste Management Association, V.42, Jan p "Alternative refrigerants and your equipment room," Burgett, Lee. Heating, Piping, and Air Conditioning, V.63, Apr p

5 Energy Efficiency & Environmental News: CFC Replacements Page 5 solar. Though comparatively small, that 5% is equivalent to twelve 1000 MegaWatt power plants. 90% of this renewable capacity was installed since Of the 5.2% of Florida s energy that comes from renewable sources, 96% comes from biomass (which in effect is indirect solar energy) and 3% comes from direct solar. That 3% is equivalent to two 750 Megawatt power plants....pinellas County s Waste to Energy (WTE) facility provides power to 55,000 homes by converting 3,000 tons of waste per day into electricity. Broward County has a similar facility. NEW FOR YOU To supplement the "Recycling in Hotels & Motels" series, the IFAS Media Library now has the English, Spanish, and Creole versions. An electronic Energy Resource Directory will be available to you soon. The directory can instantly provide you with a list of energy related media items, such as fact sheets, videos, and displays, according to a subject you select from an on-screen menu. Please contact Mike West at if you are interested in receiving a copy.