Heat Transfer and Pressure Drop During Condensation of R1234yf inside a 2.5 mm OD Microfin Tube

摘要

R1234yf has a low global warming potential of 4, compared to 1430 for R134a, and has thermodynamic properties similar to R134a, making it a promising refrigerant for next generation refrigeration and air conditioning application. The present paper reports the local condensation heat transfer coefficient and adiabatic pressure drop characteristics of a microfin small diameter tube, with a 2.5 mm outside diameter, and R1234yf and R134a refrigerants. Experimental tests were carried out for mass velocities from 50 to 100 kg m~(-2)s~(-1), vapor qualities from 0.1 to 0.98, saturation temperature from 20°C to 35°C. The results of the experiment suggest that the mass flux, saturation temperature, and refrigerant properties have a noteworthy effect on both the heat transfer coefficient and pressure drop. R1234yf shows a lower heat transfer coefficient and a lower pressure drop than that of R134a. The experimental results were compared to the predicted results obtained using some renowned correlations.