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In the Kyoto Protocol, HFCs were included in the comprehensive "basket" of greenhouse gases along with carbon dioxide, methane, nitrous oxide, PFCs and SF6. The protocol requires developed countries to first eliminate any growth in their greenhouse gas emissions that took place over the two decades (since 1990) and then collectively to further reduce their emissions 5.2% (or about 5%) below 1990 levels on average over the 2008 to 2012 time period. In the Montreal Protocol, parties have discussed the viability of HFCs as a substitute for ozone-depleting CFCs.

This report is an update of the report first published in August, 1999. It provides an objective analysis of the key aspects of HFCs in comparison with alternative fluids and technologies in the major applications involving HFCs. This study is intended to provide input to the Secretariat of the Climate Change Convention in connection with the issue of coordinating the HFC policy objectives of the Montreal Protocol (not to interfere with the smooth phase-out of ozone depleting substances through adequate availability of substitutes) and the Framework Convention on Climate Change (examining what real and cost effective opportunities might exist to reduce greenhouse gases).

The objective of this study is to document the overall performance of specific HFCs compared to other fluids and technologies in the key applications where HFCs have emerged as replacements for CFCs and HCFCs. The application areas include automobile air conditioning, residential and commercial refrigeration, unitary air conditioning, HVAC chillers, foam insulation, solvent cleaning, aerosols, and fire protection. The overall performance attributes that have been addressed include energy efficiency and global climate impact, safety, and economics.

• Figure E-1 provides a breakdown of the warming impact of greenhouse gas (GHG) emissions in the United States in l999 and a projection for 2030. In 1999, PFC, HFC, and SF6 emissions together were 2.0% of the total warming impact. Nonprocess related HFC emissions were 0.8% of the total warming impact of U.S. GHG emissions

Figure E-1: Breakdown of Greenhouse Gas Emissions in the United States
• The remaining 1.2% of total U.S. GHG emissions within the PFC, HFC, SF6 category are primarily process emissions (from manufacturing aluminum and magnesium, fugitive emissions of HFC-23 from HCFC-22 production). Fluorochemical manufacturers have committed to reduce this source of HFC-23 emissions. With the phase-out of HCFC-22 production under the Montreal Protocol, which will be largely completed by 2010 and fully completed by 2020, this major source of HFC emissions may be reduced substantially (not completely eliminated, due to continued production of HCFC-22 as a feedstock for polytetrafluoroethylene --- PTFE --- production).
• The production of various HFCs is increasing, as the phase-out of CFCs and HCFCs proceeds. However, the quantities of HFCs that are likely to be produced in the future, under present Montreal Protocol and Kyoto Protocol treatment, given inherently higher production costs and end-user prices and tight regulation of system tightness and servicing/venting practices, are significantly less than the peak of quantities of CFCs and HCFCs that were produced in the late 1980s. In Figure E-1 an estimate of the breakdown of U.S. greenhouse gas emissions in 2030 is also included. HFCs are estimated to be 2.3% of a total that assumes a high degree of stabilization of CO2 emissions.
• Global greenhouse gas emissions are broken down in Figure E-2 and parallel the U.S. breakdown, except that energy related GHG emissions (CO2) account for a larger part of the total and HFCs account for a smaller part.

Figure E-2: Breakdown of Global Greenhouse Gas Emissions
• The cumulative effect of these categories of greenhouse gas emissions on radiative forcing has been estimated by the Intergovernmental Panel on Climate Change (IPCC) for the next 50 years and is shown in Figure E-3. In 2050, HFCs will still account for less than 2% of radiative forcing.
Relative Projected Contributions of Greenhouse Gases

Source IPCC: IS92A Scenario
Figure E-3: Relative Projected Contributions of Greenhouse Gases to Radiative Forcing
• The transition from CFCs to HCFCs and HFCs has already significantly reduced the potential warming impact of fluorocarbon production, as shown in Figure E-4.

Figure E-4: GWP Weighted Fluorocarbon Production from 1980 - 2000
(Source: AFEAS, Production and Sales of Fluorocarbons)
• The preceding figures substantially overstate the net warming impact of HFCs, given the significant contribution to energy savings that the unique properties of HFCs provide in many applications. Only a small amount (about 10%) of HFCs will be used in directly emissive, non-energy consuming applications. In the remaining applications the HFC based technology generally has the lowest net warming impact, as measured by the Life Cycle Climate Performance (LCCP). In other words, the net warming impact of most HFC use is close to zero or provides a net reduction in warming.
• The LCCP is a rigorous method of calculating the cradle-to-grave warming impact of any product, including those that use fluorocarbons. The LCCP accounts for warming impacts due to direct greenhouse gas emissions from the product and to indirect greenhouse gas emissions associated with the energy consumption of the product. In applications such as domestic and commercial refrigeration, stationary and mobile air conditioning, and foam insulation, the lowest LCCP solution uses HFC refrigerants and/or foam blowing agents.
• Absent a rigorous methodology, a rough estimate of the societal cost savings provided by the use of HFCs has been made, as summarized below and presented in detail in Section 3. The annual costs, in the U.S. and worldwide, would be $17 billion and $36 billion, respectively and include increased product costs, increased energy costs, and increased costs of safety and accident damage. This is an order of magnitude estimate that clearly could be refined with a much larger analytical and data gathering effort.

The HFCs that have emerged as the preferred replacements for the CFCs and HCFCs retain the desirable safety characteristics --- low toxicity, non-flammable --- that originally lead to the widespread use of CFCs and HCFCs as refrigerants, foam blowing agents, etc. Many of these applications are in mass markets, with hundreds of millions of products in service. Table E-1 summarizes the number of refrigeration and air conditioning systems in service globally, a total on the order of 1 billion units. Over the lifecycle of this large number of units, non-flammable HFC refrigerants make a significant contribution to meeting the societal demand for safe products.

Other than the HFCs, the primary non-ozone depleting alternatives to the CFCs and HCFCs are hydrocarbons, which are highly flammable, carbon dioxide, which is higher in pressure and ammonia, which is toxic and flammable. The measures required to allow the safe use of these alternatives vary with the application, but increase the cost of the application. Given the enormous numbers of products in service, and a typical product lifecycle that includes (in addition to normal use) manufacturing, transportation, field servicing, and end of life disposal, the inherent potential for mishaps cannot be dismissed easily, even when the hazardous characteristics have been taken into account in the design. Determination of acceptable safety levels within the legal and political framework of country is a significant undertaking that is fraught with uncertainty. Similarly, verification that a product meets or exceeds a given safety level is a major undertaking and is also subject to significant uncertainties.

As the phase out of CFCs and HCFCs proceeds, various HFCs have emerged or are emerging as the preferred refrigerant, blowing agent, solvent, aerosol propellant, or fire extinguishent in a wide variety of applications. Many of the applications, such as domestic and commercial refrigeration and air conditioning are pervasive throughout modern society. Others such as solvent cleaning and fire protection address smaller, but critical niches. Where HFCs are the preferred alternative, the reason usually is that the HFC provides the most cost-effective combination of superior overall performance and safety. The use of HFCs will provide significant cost savings compared to the less cost-effective and, in many cases, less safe, poorer performing materials or processes that would be used as alternatives to HFCs.

An estimate has been prepared of the aggregate cost savings provided to society by HFCs. As presented in Section 3, the basis of the estimate is a comparison of the costs of the most viable non-HFC option with the most likely HFC option. While the approximate timeframe for this estimate is 2020-2030, when the full impact is felt of the technology choices made to replace CFCs and HCFCs, these costs have been applied to current market levels of sales and installed units, without attempting to project future market growth. This estimate of U.S. and worldwide societal cost savings provided by HFCs is summarized in Tables E-2 and E-3, respectively.

Sufficient data could not be found to attempt an estimate of the cost savings provided by the use of HFCs as solvents, aerosols, or fire extinguishents, but as discussed in Section 3, there are many critical uses of HFCs in these areas that create significant economic value. For example, metered dose inhalers are the mainstay treatment method for asthma used by several hundred million individuals worldwide. The value, both to these individuals, their families, and to society at large, in terms of quality of life, workplace productivity, and prolonging life is incalculable in monetary terms, but is extremely high.

As discussed in Section 3, these figures are an attempt to estimate the societal cost savings provided by HFCs; none of the figures are beyond dispute. However, the order of magnitude is large - more than $17 billion annually in the U.S. and $36 billion globally. The estimate would be higher if market growth were accounted for. This suggests that the issue deserves more in-depth analysis and should be considered carefully in policy decisions.

The basic contributors to LCCP are carbon dioxide emissions due to energy use and the direct warming impact of emissions. For a range of HFC applications, detailed comparisons of LCCP have been made between HFC based systems and non-HFC based alternative systems/technologies. The results in each application area are summarized briefly below.

Domestic Refrigeration

Domestic refrigerators use both a refrigerant and a foam blowing agent. Options for non-ozone depleting refrigerant and blowing agent are HFC-134a or isobutane, a hydrocarbon, for the refrigerant and HFC-245fa, other HFCs, and blends of the hydrocarbons, cyclopentane and isopentane, for the foam blowing agent. In Section 4, these alternatives are examined across the international context. As shown in Figure E-5, the major warming contribution to the Life Cycle Climate Performance (LCCP) of a domestic refrigerator is the indirect warming effect of the lifetime electric energy consumption of the appliance, regardless of whether HFCs or hydrocarbons are used as refrigerant and foam blowing agent (note that based on recently reported improved insulation performance with HFC-134a blowing agent, the TEWI plot for HFC-134a would fall between the plots for HFC-245fa and for hydrocarbons). Key points are:

• The refrigeration system of a domestic refrigerator is hermetically sealed and few units ever require any service over their lifetime. Consequently, lifetime emissions of refrigerant from domestic refrigerators are very small, less than 10% of the initial refrigerant charge. With HFC-134a refrigerant the warming impact of lifetime refrigerant emissions is negligible (and 85% less than for comparable emissions of CFC-12, which HFC-134a has replaced) and could be offset by a small (approximately 1/4 percent) efficiency increase.
• Even if 100% of the blowing agent is lost to the environment (which research shows is not the case [Kjeldsen, 2002]), the LCCP of the HFC and hydrocarbon blowing agent options are comparable, due to the superior insulating performance of HFC-245fa blown foam.
• The reduction in LCCP that has been achieved since the U.S. industry moved to the efficiency standards levels established in 2001 is much greater than the potential direct warming impacts of refrigerant and blowing agent.
• HFC and HC based designs have similar LCCP and are both environmentally sound, non-ozone-depleting design options.
• Having a diversity of environmentally sound ODS substitution options will allow each region to make ODS substitution decisions that best fit the circumstances of that region.
• Diversity of choice will result in the best solutions, considering all factors, unless confusion leads to a delayed phase-out of ODS in developing countries.

Figure E-5: LCCP for Domestic Refrigerator in the U.S.

Mobile Air Conditioning

The three non-ozone-depleting refrigerant options under consideration for mobile air conditioning are HFC-134a, carbon dioxide in a transcritical vapor cycle, and flammables (propane or HFC-152a). Flammables would be used with a secondary loop on the cold side to keep the flammable refrigerant out of the passenger compartment. The global automobile industry has invested $5 billion converting production automobile air conditioning systems from CFC-12 to HFC-134a; flammable refrigerant and CO2 systems are in the early development stage. Figure E-6 compares the LCCP for these three options, as applied in representative climatic and driving conditions in Europe, Japan, and the U.S., assuming lifetime emissions of approximately 75% of the initial refrigerant charge. The indirect impact is additional CO2 emissions from the vehicle tailpipe, due to energy consumption of the A/C and the resulting fuel consumption. The direct impact is the warming impact of refrigerant emissions. The results show only moderate differences in LCCP among the alternatives. In North America, where more miles are driven in hotter weather, the superior energy efficiency of HFC-134a based systems results in a lower overall LCCP.

Figure E-6: LCCP for Mobile Air Conditioning

Unitary Air Conditioning

The non-ozone-depleting options for residential unitary air conditioning include HFC blends (primarily R407C and R410A) and propane (HC-290). Propane would be used only with a secondary loop on the low side to transport the cooling capacity from an all-outdoor propane based cooling unit to the air handling system indoors. (Note that secondary loops have significant energy penalties) In Figure E-7 the LCCP has been compared for these options and with HCFC-22, which will be used in newly produced units of this class of equipment until the end of 2009. LCCPs have been calculated for a typical application in Atlanta, GA, at three efficiency levels - seasonal energy efficiency ratio (SEER) levels of 10, 12, and 14 Btu/Watt-hr. The 10 SEER level with HCFC-22 is now representative of the majority of the U.S. market. 12 and 14 SEER units are currently produced as well; by 2010, when HCFC-22 has been phased out for new equipment and higher energy efficiency standards are in place, the 12 SEER product with an HFC blend refrigerant is likely to be representative of a large part of the market for new equipment. The results generally show direct warming impacts due to life cycle refrigerant emissions are less than 5% of the LCCP. The differences in the indirect warming component of LCCP at different efficiency levels is much greater. While propane emissions have a negligible warming impact, the added cost to use propane safely exceeds the difference in cost between 12 and 14 SEER units, which have a much larger LCCP difference than the direct warming from refrigerant emissions.

Figure E-7: LCCP for Residential Space Conditioning in Atlanta (3 ton, 2005 Technology)

The LCCP for refrigerant options for a small commercial rooftop air conditioner are compared in Figure E-8 on a similar basis to the comparison for residential equipment, above, with similar results.

Figure E-8: LCCP for 7.5-Ton Commercial Rooftop Air Conditioner in Atlanta and Pittsburgh

Chillers

Large chillers are produced in capacities between 100 and several thousand tons, and are a highly efficient option for air conditioning large buildings. Screw chillers are commonly used between 100 and 400 tons and centrifugal chillers are commonly used in capacities over 300 tons. Figure E-9 summarizes the LCCP for the chiller technology alternatives (at 350 tons rated capacity), applied to a representative office building in Atlanta. Efficiency levels are representative of best, or nearly best, currently (in 1999) available screw, centrifugal, and direct-fired absorption technology. LCCP values for centrifugal and screw chillers fall within a +/- 5% range and refrigerant emissions account for less than 3% of the LCCP of any of the technology options.

Hydrocarbons, such as propane, have not been considered to be a viable option, due to the large charge size that would be used. Ammonia (R717) has been included as a technical option, but local codes may preclude its use.

Figure E-9: LCCP for Chillers - Best Current Technology, Atlanta Office Building

The LCCP of a typical direct-fired, double-effect Lithium Bromide-Water absorption chiller is about 65% higher than the average LCCP for the vapor compression cycle chillers. However, in practice a large portion of these machines are operated to meet peak loads only, as a means of reducing electric demand charges, and, as a result, operate for considerably fewer equivalent full load hours per year.

Commercial Refrigeration

Non-ozone depleting alternatives for supermarket refrigeration systems include the similar HFC blends R-404A and R-507, in either traditional direct expansion systems with centrally located, rack-mounted compressor systems or in a distributed system configuration or a secondary loop configuration. In addition, ammonia could be used as the refrigerant in a secondary loop configuration, assuming proper design of the mechanical equipment room and absence of local code issues. The LCCP for these configurations is compared in Figure E-10.

Figure E-10: LCCP Refrigeration in a Typical New Supermarket in the U.S.

Foam Insulation

In typical applications of plastic foam building insulation, the lifetime reduction of carbon dioxide emissions due to reduced consumption of energy for heating and cooling exceeds the direct warming impact of the blowing agent by a factor of 10 to 20. Consequently, plastic foam building insulation makes a major contribution to reducing greenhouse gas emissions.

The choice of blowing agent for building insulation is dictated by a number of factors including cost effectiveness of R-value, processing considerations, U.S. building code regulations, and safety. The much higher cost of some of the HFC blowing agent candidates will lead to their use only in applications where safety considerations dominate and in applications where insulation thicknesses are limited, conferring a premium value to maximizing the foam R-value. In many other applications for plastic foam building insulation, hydrocarbons and carbon dioxide will prove to be the most cost effective blowing agent.

Solvents

Many approaches have been taken to replace CFC-113 in solvent cleaning applications. They included use of HCFC-141b, aqueous cleaning, semi-aqueous cleaning, no clean fluxes and flammable solvents. HCFC-141b was an interim solution since it already has been phased out for most solvent applications. To date, the replacement percentage of CFC-113 by HFC solvents is probably no more than 2%.

Competing solvents to the HFCs, and not in kind technologies include: HCFC-141b, (CH3CCl2F), HCFC-123 (CF3CHCl2), HFEs, volatile methyl siloxanes, n-propylbromide, flammable hydrocarbons, alcohols and ketones, aqueous cleaning, semi aqueous cleaning, no clean fluxes, and inert gas soldering.

Since both HFC-43-10 and HFC-365mfc are mild solvents and either high priced or being used in blends with higher priced solvents, based on general market data, they are being utilized only for the cleaning of high value added parts where good solvent compatibility and stability would be an issue. Furthermore, the use of higher end vapor phase degreasers with high freeboards, and secondary cooling systems are required and economically justified in order to minimize the loss of expensive solvent.

The 3M company carried out a batch metal cleaning study to calculate the Total Environmental Warming Impact (TEWI) for HFE-7100, HCFC-141b, and compared the values to an aqueous and a semi-aqueous cleaning process. The vapor phase degreaser used extended freeboard and secondary cooling coils to minimize vapor loss. There was a 1-minute dwell time in the freeboard and a 1-minute dwell time in the vapor zone. The TEWI for HFC-43-10 was estimated based on the similarity of the drag out loss curve for HFC-43-10 compared to HFE-7100 and similarity of the boiling points. The data are plotted in Figure E-11.

The total use of HFC-43-10 has been estimated to be less than 2 million pounds per year which translates to <3.2 × 10-1 million metric tonnes carbon equivalent (MMTCE). The use of HFC-365mfc as a solvent is under development with an industrial-scale plant expected to come on stream at the end of 2002.

Figure E-11: LCCP for Metal Cleaning Alternatives

Unlike refrigeration, air conditioning, and foam applications, the use of aerosols entails primarily the dispersal of chemicals, and the indirect contributions from this spraying are minimal. Therefore, instead of carrying out LCCP analyses, estimates have been made for the amount of greenhouse gas emitted expressed in units of million metric tons of carbon dioxide equivalent. The estimated embedded energy and GWP of the fugitive emissions associated with manufacturing the aerosol propellant is included in these figures. Note that much of current Metered Dose Inhaler (MDI) production still use CFCs, under a Montreal Protocol essential use exemption. The conversion to HFC-134a or HFC-227ea will occur over the next 5-10 years, as product reformulations are completed and regulatory bodies, such as the U.S. Food and Drug Administration (FDA) approve HFC MDIs for patient use.

The total emissions of HFCs in all aerosol applications is projected to be 4.1 MMTCE by 2010, 5% of overall HFC emissions [EPA, 2001]. The increasing use of HFC-152a in certain specialty aerosols has helped to reduce the business as usual aerosol scenario by almost 2.75 MMTCE since 1999.

HFCs are important halon substitutes, particularly in occupied areas where space and weight are constrained, or speed of suppression is important. HFC use for fire fighting represents a very small share of total use. About 50% of the previous halon uses have been replaced with not-in-kind, non-ozone depleting alternatives. These include water-based systems, foam, dry powder, and fire-protection engineering approaches involving risk analysis, prevention steps and early detection systems combined with portable extinguishing equipment. About 25% have been replaced with non-halocarbon gaseous agents such as inert gas mixtures or carbon dioxide. Despite the consumption phaseout in developed countries, there remain some critical halon uses in existing and new applications, such as civil and military aircraft, military vehicles, and other specialized high-risk situations. Critical use halon comprises 3 - 4% of the fire fighting market. Only about 20% of the former halon market has been replaced by HFCs.

In contrast to the refrigeration and air conditioning equipment discussed in previous sections of this report, fire suppression systems are essentially non-emissive systems that sit idly while awaiting the mishap against which they are intended to protect. The fire detection system consumes a low level of electrical power, and small amounts of energy are consumed during periodic operating tests.

The systems are material intensive, and can include a significant amount of steel pressure vessels to store the fire suppression agent and steel piping to distribute the fire suppressant. The embodied energy in these materials, as well as the embodied energy in manufacturing the fire suppression material is the most significant energy input over the life cycle.

Emissions of the fire suppressant can be categorized as non-fire and fire emissions, i.e., releases of the fire suppressant to extinguish a fire. Modern fire suppressant systems do not leak and do not require discharge testing. Consequently, current practices hold emissions, both fire and non-fire related, to 1-3% annually of the installed base. Releases to suppress a fire in practice do not occur very frequently and currently are estimated to be approximately 1.5% of the installed bank. Over the 10 to 25 year typical system useful life, most of these systems are never called upon to suppress a fire. At the end of the useful life of a system, the fire suppressant can be recovered for recycling or reclaimed for transformation into non-GWP substances. The warming impact of HFC emissions from fire fighting is approximately 0.006% of the warming impact of all GHG emissions.

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