Condensation heat transfer characteristics and generalized correlations of R404A, R448A, and R454C in a plate heat exchanger

Although numerous studies have been carried out on alternatives to R134a and R410A to cope with regulations, the heat transfer characteristics of refrigerants with a low-global warming potential to replace R404A in a plate heat exchanger (PHE) have not yet been intensively investigated. Generally, R448A has been considered as a short-term alternative to R404A, while R454C has been nominated as a long-term alternative to R404A. In this study, the thermal and hydrodynamic characteristics of R404A, R448A, and R454C in a PHE during condensation are experimentally investigated at vapor qualities (x) of 0.2–0.8, mass fluxes (G) of 15–35 kg m⁻² s⁻¹, heat fluxes (q”) of 3–7 kW m⁻², and saturation temperatures (T_sat) of 20–27 °C. The results of the analysis show that the condensation heat transfer coefficient (HTC) and frictional pressure drop (FPD) are predominantly affected by the x and G, while the q” barely affects the FPD. The average condensation HTC and FPD of R448A and R454C exceed those of R404A by 17.25–20.57% and 9.6–10.72%, respectively. Additionally, new generalized correlations of the condensation Nusselt number and frictional pressure drop for R404A, R448A, and R454C in a PHE are developed with mean relative deviations of −1.905% and 1.01%, respectively.