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Reduced-order Model to Estimate Safe Flammable Refrigerant Charge Limits for a One-room Air Conditioner

Publication Type
Conference Paper
Journal Name
Proceedings of 25th International Congress of Refrigeration
Book Title
Proceedings of the 25th IIR International Congress of Refrigeration
Publication Date
Page Numbers
1417 to 1425
Publisher Location
Paris, France
Conference Name
25th IIR International Congress of Refrigeration
Conference Location
Montreal, Quebec, Canada
Conference Sponsor
International Institute of Refrigeration
Conference Date

The Heating, Ventilation, Air-Conditioning and Refrigeration (HVAC&R) industry is currently transitioning away from high global warming potential (GWP) hydrofluorocarbon (HFC) refrigerants. However, many lower-GWP alternatives are flammable. Current safety codes restrict use of all flammable refrigerants; revision of the codes is needed to facilitate wider use of flammable alternatives. Hence, information is needed to enable reliable estimates of safe charge limits for flammable refrigerant options for different HVAC&R applications. A reduced-order-model (ROM) was developed and validated to help estimate safe charge limits based on computational fluid dynamics (CFD) simulations of refrigerant releases in a single room for a range of parameters. Validation of the ROM vs. the CFD results showed good general agreement for mean refrigerant concentration. The average error was 0.67% with a maximum error of 15%.