The low GWP (Global Warming Potential) refrigerant R1234ze(E) is a potential alternative of R134a. This study puts the emphasis on the comparison of the flow boiling pressure drop and heat transfer of R134a and R1234ze(E) in a dimpled flat duct. For the air-conditioning applications, the experiments are conducted at mass flux from 100 to 200 kg m⁻² s⁻¹, saturation temperature from 5 to 15 °C, heat flux from 2.5 to 10 kW m⁻², and vapor quality from 0.1 to 0.95. The results show that the frictional pressure gradient of R1234ze(E) is 1.10 to 1.27 times that of R134a. The characteristics of the flow boiling heat transfer coefficient of R1234ze(E) are similar to R134a. The increasing flow boiling heat transfer coefficient with vapor quality in the tested range implies the convective evaporation dominates the heat transfer. It is also observed that the flow boiling heat transfer coefficient visibly increases with a rise in mass flux and decreases with the saturation temperature increment due to the increase in vapor to liquid density ratio. The enhancement effect of heat flux on the flow boiling heat transfer shows up at the highest value of 10 kW m⁻² only. The heat transfer coefficient ratio of R1234ze(E) to R134a increases from 0.89 to 1.20 with an increase in vapor quality. The comparison of frictional pressure gradient and heat transfer characteristics between R1234ze(E) and R134a has been discussed from the viewpoint of fluid properties.

全球变暖潜能值低的制冷剂R1234ze（E）是R134a的潜在替代品。这项研究的重点是比较波纹管中R134a和R1234ze（E）的沸腾压降和传热。对于空调应用，实验的质量通量为100至200 kg m ^-2 s ^-1，饱和温度为5至15°C，热通量为2.5至10 kW m ^-2，蒸气质量从0.1到0.95。结果表明，R1234ze（E）的摩擦压力梯度是R134a的1.10至1.27倍。R1234ze（E）的沸腾传热系数的特性与R134a相似。在测试范围内，随着蒸气质量的增加，沸腾传热系数增加，这意味着对流蒸发在传热中占主导地位。还观察到，由于汽液密度比的增加，沸腾传热系数随着质量通量的增加而明显增加，并且随着饱和温度的增加而减小。热通量对流动沸腾传热的增强作用在最高值为10 kW m ^-2时出现只要。随着蒸汽质量的提高，R1234ze（E）与R134a的传热系数比从0.89增加到1.20。从流体性质的角度，讨论了R1234ze（E）和R134a之间的摩擦压力梯度和传热特性的比较。