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Low GWP refrigerants and flammability classification.

Author(s) : CLODIC D.

Summary

Research of new refrigerants in the last 15 years has led to select either "old" refrigerants such as hydrocarbons, ammonia, and CO2 or recently unsaturated HFCs such as R1234yf. Toxicity issues forbid the use of possible toxic refrigerants as it has been demonstrated by the failure of both DP1 and AC1 refrigerant blends. Flammability is a different matter because lean flammable substances can be used if properly handled. Since 1995 research has been carried out in Japan, Europe, and the US for flammability classification of refrigerants. The burning velocity and the minimum ignition energy (MIE) are fundamental physical properties allowing the classification of refrigerants according to their flammability. This classification is of importance in order to mitigate flammability risks in a rational manner. ISO 817 draft has elaborated a new threshold in order to differentiate between moderate flammable substances. In fact the burning velocity and the MIE allow ranking precisely risks related to the use of flammable substances. Several methods have been proposed for the calculation of flammability of refrigerant blends such as the RF numbers. The future of low GWP refrigerants is definitively related to risk mitigation of either toxicity (for ammonia only) or flammability. A new international classification is necessary in order to take appropriate measures to use low-GWP refrigerants safely depending on the refrigerant charge and the refrigeration capacity.

Details

  • Original title: Low GWP refrigerants and flammability classification.
  • Record ID : 2011-0065
  • Languages: English
  • Subject: Regulation
  • Source: Measures to address climate change. 2010 International Symposium on Next-generation Air Conditioning and Refrigeration Technology: February 17-19, Tokyo, Japan.
  • Publication date: 2010/02/17

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