In developed countries, the only replacements for the fluid CFC-12 in refrigerators and freezers have been HFC-134a and isobutane (R-600a). Developing countries have chosen the same replacements, but some still utilize CFC-12; here, the complete conversion of new equipment from CFC-12 is not expected until 2001-2002. Globally, in 1996 to isobutane was used in about 8% of new appliances (UNEP, 1998a). Isobutane accounts for a much higher and growing percentage in Northern European countries such as Germany, where it is used in virtually all new domestic appliances. It is estimated that isobutane currently is the coolant used in 45%-50% of domestic refrigerator and freezer sold in Western Europe. Projected use and emissions of HFC-134a are shown in Table A3.2.
HFC emission reductions achieved during servicing and through recovery of the refrigerant upon disposal of appliances are costly. Next to economic incentives, regulations (as already exist for CFC-containing appliances in several countries) would probably be required to obtain significant emissions reductions through HFC recovery (March, 1998). One study (Harnisch and Hendriks, 2000) reports a value of US$334/tCeq for the recovery of HFCs from refrigerators; the larger part of this is the cost for the transport and collection scheme.
Product liability, export market opportunities, and regulatory differences among regions are likely to be significant factors in determining the choice between isobutane and HFC-134a systems. Isobutane may well account for over 20% of domestic appliances globally by the year 2010. Published estimates suggest that isobutane systems are US$15 to US$35 more expensive than HFC-134a systems (Juergensen, 1995; Dieckmann et al., 1999). These costs would translate into a cost effectiveness of US$600/tCeq due to the relatively small refrigerant charge (about 120 g of HFC-134a).
The primary refrigerants used in this sector are R-404A and HFC-134a; usage of R-407C and R-507 is relatively small. Hydrocarbons are being applied in smaller direct expansion systems and in both small and large systems with a secondary loop, whereas ammonia is mainly applied in larger systems with secondary loops (UNEP, 1998a). Projected consumption and emissions of HFCs are shown in Table A3.2.
Historical emission rates of CFC refrigerants from the commercial refrigeration sector were 30% or more of the system charge per year. Regulations have resulted in improved system designs and service practices with significantly lower emissions in many countries (UNEP, 1998a; IEA, 1998). These practices are being carried over to HFC systems and the emissions savings are reflected in the projections shown in Table A3.2 (UNEP, 1999b). March (1998) estimated that refrigerant emissions could be further reduced through better containment and recovery by an additional 30% to 50% in 2010 for Europe. In many developing countries, the supermarket refrigeration units are often produced by small and medium enterprises to lower quality standards, leading to considerable emissions of HFCs. The existing stock of supermarket refrigerators continues to operate with CFC-12 and HCFC-22.
The use of hydrocarbons and ammonia as refrigerants in this sector is growing from a small base. Several large commercial refrigeration manufacturers are developing systems using carbon dioxide which are expected to enter the market shortly. The HFC projections shown in Table A3.2 are based upon the assumption that less than 10% of the systems will use ammonia, hydrocarbons, and carbon dioxide in 2010.
Most existing residential air conditioning and heating systems (unitary systems) currently use HCFC-22 as the refrigerant; in the manufacturing of new systems HCFC-22 is being displaced by HFC blends, and to a lesser extent, by propane in some systems. In developed countries, the Montreal Protocol and more stringent national regulations are leading to a replacement of HCFC-22 in virtually all new equipment, ultimately by 2010. The leading HFC alternatives are R-407C and R-410A (UNEP, 1998a), the latter particularly for smaller units in the developed countries at present. In developing countries, HCFC-22 will be available for many more years and the use of HFC blends may remain small. Split HC based air conditioning equipment is produced by some smaller European manufacturers; production of these units is being announced by others. Estimated consumption and emission amounts for 2010 are shown in Table A3.2.
In small water chillers, applying a variety of compressor types, there is emphasis on the use of R-407C. For large water chillers that apply centrifugal compressors, the primary alternatives to CFCs are HFC-134a and HCFC-123. HCFC-123 is used in virtually all low-pressure chillers since it has a very high energy-efficiency and so far no highly efficient, low-pressure non-ODS alternative has become available (Wuebbles and Calm, 1997). Certain existing high-pressure HFC equipment or new low pressure HFCs may take over the low-pressure market gradually in the near future (IEA, 1998). Ammonia chillers form an important replacement and they are already in use in some regions. In large chillers, there is some use of water as a refrigerant, particularly in Northern Europe, where the water can also be used in ice slurry form as the cooling agent in the secondary loop. Use of hydrocarbon refrigerants for chillers is growing from a small base. Estimated consumption and emissions of HFCs are shown in Table A3.2.
Continued improvement in emissions reductions is anticipated. In 1994, the annual emission rates from low-pressure CFC chillers were estimated at 7% and for high pressure CFC-12 chillers at 17% (UNEP 1998a); for current new low (HCFC-123) and high pressure chillers the emissions are estimated at less than 2% and 8%, respectively.
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