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Analysis of the P-t and T-s Phase Boundary In Discriminating Suitable Low Global Warming Potential and Low Flammability Refrigerants

by Moonis R Ally, Vishaldeep Sharma, Kashif Nawaz
Publication Type
Conference Paper
Book Title
Refrigeration Science and Technology Proceedings; 25th IIR International Congress of Refrigeration
Publication Date
Page Numbers
804 to 810
Publisher Location
Paris, France
Conference Name
25th IIR International Congress of Refrigeration (ICR 2019)
Conference Location
Montreal, Canada
Conference Sponsor
International Institute of Refrigeration
Conference Date

Although several alternative low GWP refrigerants including natural have been proposed, the HVAC industry consensus on how to deal with the attendant issues is still evolving. This paper provides a qualitative and quantitative insight into the peculiar phase boundary shapes of refrigerants, essential for understanding their application, and in evaluating existing and future refrigerants. The methodology is firmly grounded in the thermodynamics of phase equilibria and the criteria of positive-definiteness, a direct consequence of the Second Law and the existence of intermolecular forces (IMF). The formal methodology is strikingly easy to implement in practice and explains clearly why certain refrigerants display “re-entrant” behavior while others do not. The paper shows how an evidence-based selection can be made among the 40 refrigerants analyzed in this study.
Keywords: Low GWP, alternate refrigerants, heat pumps, VLE