Flammability inhibition effects of R227ea, R125, R134a, and R744 on 3, 3, 3-trifluoropropene (R1243zf). (February 2022)

• Record Type: Journal Article
• Authors: Wu, Xi; Zhang, Xinjie; Tang, Fengyi; Xu, Shiming; Dang, Chaobin; Sun, Dexin
• Is Part Of: International journal of refrigeration. Volume 134(2022)
• Page Start: 55
• Page End: 63
• Publication Date: 2022-02
• Subjects: Refrigerant -- Flammability limits -- Hydrofluoroolefin -- HFO-1243zf -- Retardant; Frigorigène -- Limites d'inflammabilité -- Hydrofluoroléfine -- HFO-1243zf -- Retardateur; Refrigeration and refrigerating machinery -- Periodicals; 621.56
• DOI: 10.1016/j.ijrefrig.2021.11.019
• Languages: English
• ISSNs: 0140-7007

Abstract

Highlights: Flammability limits of HFO-1243zf were measured, and estimated by three methods. CSRs decrease in the order: R744/R1243zf>R134a/R1243zf>R125/R1243zf>R227ea/R1243zf. Mechanisms of flammability inhibition effects of retardants on R1243zf were analyzed. F/H ratio and CF3 group determine the flame suppression ability of a retardant. Abstract: 3, 3, 3-trifluoropropene (R1243zf or HFO-1243zf) has low global warming potential, which is expected to be an excellent alternative to hydrofluorocarbon refrigerants in air conditioning and refrigeration systems, but its flammability hinders the practical applications. This paper reports the experimental results of the flammability inhibition effects of carbon dioxide (R744), 1, 1, 1, 2, 3, 3, 3-heptafluoropropane (R227ea), pentafluoroethane (R125), and 1, 1, 1, 2-tetrafluoroethane (R134a) on R1243zf. The measured critical suppression ratios decrease in the order: R744 (3.1) > R134a (1.42) >R125 (0.68)> R227ea (0.58), which are also predicted by group contribution method. The flammability limit range of R1243zf was estimated as per three methods, and the closest estimation values to tested data was obtained by using the Jones' method (the stoichiometric concentration for combustion method). Finally, the mechanisms of flammability inhibition effect differences of R744, R227ea, R125, and R134a on R1243zf were analyzed, from the views of the combustibles or oxidants dilution, combustibles and oxidants isolation, and/or free radical production and consumption. A hydrofluorocarbon flame retardant that has the big F/H ratio and produces much free radical CF3 during its thermal decomposition, exhibits the good flammability inhibition efficiency to R1243zf.