Performance of a Flat-Tube Louvered-Fin Automotive Condenser with R1234yf

Abstract

Numerical simulation of a mini-channel, flat-tube, louvered fin, automotive condenser is performed to study the heat rejection rate, pressure drop and performance of the heat exchanger. The simulation study is carried out for the refrigerant R1234yf. The properties of R1234y are obtained from REFPROP software. The moist air properties are calculated from those of dry air and water vapor using suitable correlations. To select the input data, the cycle performance is carried out for a standard vapor compression refrigeration system working with R1234yf between the temperature limits of [Formula: see text]C on the low-pressure side and [Formula: see text]C on the high-pressure side. The condensation process is taken into account in three sections, namely, the superheated, two-phase and the subcooled regions. A custom code is prepared in MATLAB to solve the simultaneous equations of heat transfer from refrigerant to inside tube wall, inside tube wall to outside tube wall and outside tube wall to moist air. The simulation results show the sensible heat transfer during desuper heating to be very small compared to the condensing region. Results are reported for the pressure variation along the refrigerant flow passage in the desuper heating, two-phase and subcooling regions. The heat-transfer coefficient is found to be the highest in the two-phase region for higher dryness fractions. The effect of inlet air velocity is less compared to that of the inlet air temperature on the heat rejection rate.