The objective of this paper was to measure and compare the heat transfer coefficient and pressure drop of R404A and two potential replacement candidate refrigerants with a lower global warming potential, R448A and R452A. Experiments were conducted inside a 4.7 mm horizontal tube at mass fluxes ranging from 100 to 800 kg m${}^{-2}$ s${}^{-1},$ and at three different saturation conditions (40, 50, and 60 ^∘C). R448A and R452A are zeotropic refrigerant mixtures, with temperature glides of approximately 4 ^∘C and 3 ^∘C, respectively. The Cavallini et al. (2006) correlation predicted the heat transfer data best for all three refrigerants, once mixture effects were accounted for using the equilibrium Silver (1947), Bell and Ghaly (1973) method. The Haraguchi et al. (1994) correlation predicted the R484A frictional pressure drop data best (mean average percent error, MAPE = 15%), while the Friedel (1979) correlation predicted the R404A (MAPE = 15%) and R452A data (MAPE = 14%) pressure drop the best. The heat transfer coefficients of R404A were slightly higher than those of R452A and slightly lower than those of R448A at equivalent conditions. At the same mass flux, (G = 600 kg m${}^{-2}$ s${}^{-1}$), R448A and R452A pressure drops are on average 81% and 3.3% higher than that of R404A. For the same cooling capacity and condenser design, the pressure drop of R404A and R452A are approximately the same and the pressure drop of R448A is approximately 16% lower than that of R404A.

本文的目的是测量和比较R404A和具有较低全球变暖潜势的两种潜在替代候选制冷剂R448A和R452A的传热系数和压降。实验在4.7 mm水平管内进行，质量通量范围为100至800 kg m${}^{-2}$ s${}^{-\mathrm{1个}}，$并且在三个不同的饱和条件下（40，50，和60 ^∘ C）。R448A和R452A是非共沸混合制冷混合物，具有大约4温度滑移^∘ C和3 ^∘C分别。Cavallini等。（2006年）相关性预测了所有三种制冷剂的最佳传热数据，一旦使用平衡银（1947），贝尔和盖利（1973）方法考虑了混合效应。原口等。（1994）相关性预测R484A摩擦压降数据最佳（平均平均误差百分比，MAPE = 15％），而Friedel（1979）相关性预测R404A（MAPE = 15％）和R452A数据（MAPE = 14％）压力放下最好的。在相同条件下，R404A的传热系数略高于R452A，但略低于R448A。在相同的质量通量下，（G = 600 kg m${}^{-2}$ s${}^{-\mathrm{1个}}$），R448A和R452A的压降平均比R404A高81％和3.3％。对于相同的冷却能力和冷凝器设计，R404A和R452A的压降大致相同，R448A的压降比R404A降低约16％。