31 December 2008
In order to develop alternative refrigerants and promote the use of products that employ alternative refrigerants, the Ministry of Economy, Trade and Industry (METI) of Japan supports R&D activities of industries, non-profit research laboratories and universities. This article describes details of the “Development of Non-fluorinated Energy-saving Refrigeration and Air Conditioning Systems” project.
HFCs, PFCs, and SF6 have been widely used in a variety of applications, as alternatives to ozone-depleting substances. However, all of these gases are major contributors to the greenhouse effect and so, along with carbon dioxide, methane, and nitrous oxide, have been recognised as belonging to the group of gases of which emissions must be reduced, in accordance with the Kyoto Protocol adopted in December 1997. HFCs are alternative fluorinated fluids that are used as refrigerants, foaming agents for thermal insulating materials, and propellants.
Figure 1 shows the trend of emissions of HFCs, PFCs, and SF6 in key countries. Although emissions of these gases in Japan have been reducing steadily in recent years, predictions of future emissions are not optimistic, as shown in Table 1. For example, predicted emissions of these gases in 2010 are higher because HCFC refrigerants are expected to be replaced by HFCs, and the emission of HFCs from discarded refrigeration and air conditioning equipment is expected to increase sharply. Refrigeration and air conditioning equipment will be a major source of greenhouse gases other than carbon dioxide.
In order to develop alternative substances and promote the use of products that employ alternative substances, the Ministry of Economy, Trade and Industry (METI) supports R&D activities of industries, non-profit research laboratories, and universities. As shown in Figure 2, the New Energy and Industrial Technology Development Organization (NEDO) manages METI-subsidised projects. NEDO is now also responsible for R&D project planning and execution, project management, and post-project technology evaluation functions.
Due to the regulation of specific CFCs and HCFCs as part of the Montreal Protocol for protecting the ozone layer, Japan is obligated to phase out the production and use of CFC and HCFC refrigerants. For this reason, HFCs have been developed as alternatives to ozone-depleting substances. At an early stage, manufacturers of refrigeration and air conditioning equipment successfully replaced CFCs and HCFCs with HFCs in their most common models. Air conditioners with non-fluorinated refrigerants that contribute minimally to the greenhouse effect have been partly commercialised; however, their use is not yet widespread, due to safety concerns and poor energy efficiency. In general, it is extremely challenging technically to use non-fluorinated refrigerants in air conditioners, and refrigerants have not advanced considerably beyond the research stage. In order to commercialise them, basic equipment and energy-efficient, safe, and secure processes must be comprehensively developed. NEDO has developed and/or improved refrigeration and air conditioning systems with excellent safety and functionality. These systems use non-fluorinated substances as refrigerants, which do not deplete the ozone layer and have a low global warming potential (low GWP). Objectives of the project also include conservation of energy and reduction in overall environmental impact. As mentioned earlier, the project is called “Development of Non-fluorinated Energy-saving Refrigeration and Air Conditioning Systems,” and its duration is from FY2005 to FY2009. The author is currently serving as the project leader. Table 2 shows the themes, companies, periods, and refrigerants developed under this project. R&D of refrigeration and air conditioning systems that employ a wide variety of natural refrigerants has been carried out. Development of low-GWP refrigerants, including HFO1234yf and its mixture, was begun in 2008.