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Fractionation, release testing and flammability evaluation of novel refrigerants comprising R-744 and fluorocarbons.

Number: 2461

Author(s) : GRUNDY D., WEBSTER V. A., SEETON C. J., LOW R. E.

Summary

As the world becomes more focused on climate change, there is growing willingness to bring about rapid reduction in emissions of greenhouse gases. Refrigerants and blends are used throughout the world in a wide range of applications from agriculture, shipping, automotive and medical. There is a drive from each sector to identify new lower GWP (global warming potential) alternatives to replace currently used fluids while at the same time ensuring that performance and safety are acceptable. Many applications are now using or evaluating flammable fluids as a means of achieving GWP reduction while staying close to the properties of existing refrigerants. However, some applications still require non-flammable fluids. This study has identified several non-flammable carbon dioxide (CO2) rich blends that offer potential as replacements for existing fluids while maintaining excellent thermodynamic properties. Two of these blends are R-473A and LFR3. This paper will present the results of studies conducted on fractionation (vapor leakage) of these fluids from systems to determine actual compositions during the leak process over a wide range of ambient temperatures. These compositions were subjected to ASTM E681 [1] flammable limit determination testing to assess whether leakage from a system could ever generate a flammable composition. Modelling of the leakage experiments with the NIST REFLEAK [2] software will also be presented. A novel flow apparatus has been developed to study what happens when high-pressure refrigerants containing R-744 are expanded to atmospheric pressure. This is relevant in understanding phase behaviour when refrigerant is released by pressure relief valve or pipe failure and when liquid refrigerant is expanded in a refrigeration cycle to low evaporator pressures. Results quantifying the flash vapor formation and dry ice formation will be presented.

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  • Original title: Fractionation, release testing and flammability evaluation of novel refrigerants comprising R-744 and fluorocarbons.
  • Record ID : 30030740
  • Languages: English
  • Subject: Technology
  • Source: 2022 Purdue Conferences. 19th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2022

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