Ranking of Refrigerants by Different Assessment Methods

All chemicals and products have certain impacts on the environment, e.g. according to their energy consumption, toxicity, and contribution to climate change. The aim of a life cycle assessment (LCA) is to investigate and evaluate the environmental impact of a product or service and to find the least harmful option. Because of its holistic nature, LCA is an important instrument for decision making in the environmental sector. For that reason, various approaches have been developed using different calculation factors (Dreyer et al. 2003, Gloria et al. 2006, Guinee et al. 2002, Goedkoop & Spriensma 2001). Because of the commitments in the Kyoto Protocol, hydrofluorocarbons (HFC) and perfluorocarbons (PFC) must be phased out and suitable replacements must be found. This applies also to the airconditioning systems (A/C) in passenger cars. In almost all A/C the refrigerant nowadays used is 1,1,1,2tetrafluoroethane (R134a) with an annual market growth in Germany of about 4 %, the largest in the field of refrigeration and air-conditioning. According to the German Federal Environmental Agency (Schwarz 2005), the A/C sector of passenger cars is the main emission source of fluorinated greenhouse gases in 2002, followed by commercial and industrial refrigeration. In combination with the high fleet number of air-conditioned cars, and the fact that the percentage of passenger cars equipped with A/C is at 95 % (Schwarz 2005), this sector is of great interest regarding potential impact reduction for ozone depleting substances (ODS), greenhouse gases, and energy consumption. In the present work, the main focus is on comparison of three assessment methods, used to evaluate the environmental impact of refrigerants used in A/C by means of partial order.