15 September 2011


In recent years, to meet the Montreal Protocol requirements, reduction of the
fluorocarbon refrigerants designated by the Protocol has almost been completed in Japan by replacing them with HFCs that have zero-Ozone Depletion Potential (ODP). However,
although HFCs have zero-ODP, some HFCs known as alternatives to HCFCs have high Global Warming Potential (GWP). Now it has become imperative to find refrigerants that could satisfy the requirements of both the Montreal Protocol and the Kyoto Protocol at the
same time. When choosing refrigerants, we should not focus on GWP only since the degree of global warming impact is greatly affected by various factors such as capacity of
equipments in use, safety, economy, and Life Cycle Climate Performance (LCCP). When used in heat pump systems, those factors vary from country to country according to the
climate of regions, their operating conditions, the way they are used, electricity rate system, and applicable laws and regulations. In this paper, we propose a notion of diversity of
refrigerant choice, in which we suggest the most suitable refrigerants for various applications in various regions by employing the best available technology. Our proposal includes not
only developed countries but also developing countries whose contribution to global warming has been becoming more significant than before due to their rapid economic growth.