R1234YF Heat Transfer Coefficient During Condensation in a Mini-Channel Multiport Tube

Resumen

The use of micro- and mini-channels in heat exchanger has increased in recent decades. They contribute to improving efficiency and reducing refrigerant charge and compactness of heat exchangers. The aim of this study is to experimentally determine heat transfer coefficient in mini-channels two-phase flow processes with the new low GWP refrigerant R1234yf and compare it with the values provided by some of the correlations encountered in the existing literature.In the existing literature there are a few publications studying the refrigerant R1234yf because of its recent creation. R1234yf cannot be immediately charged into the system where there was an ozone-depleting refrigerant before. Several modifications must be made such as specific oil for the compressor.An installation for the study of condensation processes has been constructed at the Technical University of Cartagena. The more relevant results of heat transfer coefficient are presented in this paper. R1234yf was measured flowing through an aluminium square multiport tube with a hydraulic diameter of 1.17 mm and compared with R134a. The influence of saturation temperature (or pressure), flow velocity, and vapour quality in heat transfer coefficient has been studied. The values considered for these variables are: saturation pressure corresponding to 30, 35, 40, 45, and 50 °C; flow velocities from 350 to 945 kg s−1·m−2; vapour quality from 0.07 to 0.94.