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This report is an update of the report having the same title that was first published in August, 1999. During the 2½ years since August, 1999, new technology alternatives have emerged and new information has been developed that is incorporated in this volume.

In the Kyoto Protocol, HFCs were included in the comprehensive set of greenhouse gases along with carbon dioxide, methane, nitrous oxide, and other trace gases whose emissions from developed countries are to be collectively reduced 5.2% (or about 5%) below 1990 levels. At the November, 1998 meeting of the parties to the Montreal Protocol, the issue was raised of the viability of HFCs as a long-term substitute for CFCs and HCFCs, if their use is to be restricted in any way under the terms of the FCCC/Kyoto Protocol.

This report 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 approaches of the Montreal Protocol and the Framework Convention on Climate Change.

Due to the short time that was available for its preparation and the breadth, depth, and quality of the relevant published work that precedes this effort, this document assembles a coherent review of the technical issues --- energy, environmental impact, safety, and economics --- surrounding the use of hydrofluorocarbons (HFCs) as refrigerants, solvents, foam blowing agents, aerosol propellants, fire extinguishents, etc. This study relies heavily on previously published sources for estimates of energy impact and warming impacts and for safety assessments.

The range of products that use, or potentially use, HFCs includes many that are inextricably associated with the high standard of living of the developed world and that are basic to increasing the standard of living of the less developed countries. Therefore, the economic impact --- the basic impact on the cost to consumers to buy and operate the wide range of products that rely on HFCs or alternate fluids or technologies --- is a major factor.

Objective

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 unitary air conditioning, HVAC chillers, automobile air conditioning, residential and commercial refrigeration, 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.

An inherent challenge of a study of this nature is to simplify the vast complexities of and differences between the real world applications while retaining and addressing the essence of the comparative aspects of HFCs with alternative fluids and technologies. The basic approach that we have followed is to define a prototypical application (as summarized in Table 1-1) to represent each application area and to develop an internally consistent comparison of the HFC based equipment with the alternatives. The approach is similar to, and draws heavily upon, the approach followed in the Alternative Fluorocarbon Environmental Acceptability Study/Department of Energy (AFEAS/DOE) sponsored TEWI 1, 2, and 3 studies. Consequently, the choice of the prototypical application has been aligned with the examples in the TEWI-3, where appropriate. The assessment has been broadened to encompass safety and economic issues as well. The treatment of each application includes an introductory discussion describing the range of products used and the prototypical system that was selected to represent the category. The discussion qualitatively addresses the key and/or unique performance requirements in the application, the economic drivers, and safety aspects. Alternative technologies are described. An analysis of energy consumption (where relevant) and life-cycle direct/indirect global warming impacts has been conducted, expressed in terms of LCCP. The extent to which energy efficiency standards tend to drive all alternatives to a common energy impact will be discussed, along with economic implications. Safety has been assessed primarily in terms of toxicity and fire risk. Where available, published risk analyses have been cited to provide additional perspective. Economic factors have been discussed in terms of both consumer cost impact and manufacturer investment impacts. A detailed analysis of these cost impacts is outside of the scope of this work, but relevant literature is cited and, as appropriate, rough estimates have been prepared.

The TEWI/LCCP analysis methodology is rigorous and consistent with the methodology established in the AFEAS/DOE sponsored TEWI studies (in which Arthur D. Little was one of the two contractors responsible for developing the methodology and performing the analysis).

Table 1-1: Prototypical Applications for HFC Study

The basic concept of both the Total Equivalent Warming Impact (TEWI) and the Life Cycle Climate Performance (LCCP) is, for a given product or activity, to rigorously identify all of the warming impacts due to the use of the product through its lifetime. The TEWI methodology explicitly seeks to identify both the "direct" effect of greenhouse emissions from the product and the "indirect" effect of carbon dioxide emissions related to the energy consumption of the product.

The LCCP concept corrects a few specific oversights that have typically occurred in the practice of TEWI analysis:

• Failure to include the embodied energy and trace greenhouse gas emissions associated with fluorocarbon production in the total warming estimate
• Inappropriate use of a 100 year integration time horizon (ITH) in conjunction with certain long-lived greenhouse gases
• An LCCP analysis accounts for end of product life loss/emission of working fluids. Most of the major TEWI studies that have been published have explicitly addressed end of life disposition of the fluorocarbon inventory.

Not all published TEWI studies have been guilty of these oversights, but the LCCP measure can be taken as a more rigorous measure of warming impact due to its explicit identification of these issues.

In the context of this study, the 100-year ITH is an appropriate, if conservative choice of integration time frame. The atmospheric lifetime of CO2 exceeds 100 years. In order to properly account for its environmental impact, an ITH of at least 100 years is needed. None of the HFCs of practical interest have atmospheric lifetimes greater than 50 years, and a longer ITH would yield a lower value for the GWP.

Table 1-2 summarizes the GWP values (Climate Change 95) of the HFCs of interest and includes an estimate of the embodied energy and prorata share of the GWP of fugitive emissions based on data summarized in Appendix A. As discussed in Appendix A, data was available for HFC-134a, but not the other HFCs. Values for the other HFCs have been extrapolated from HFC-134a. The impact on the effective warming is small, well within the ±35% accuracy of the GWP values.

Table 1-2: Global Warming Properties of HFCs

1. Source: Climate Change 1995
2. Source: See Appendix A

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