Condensation heat transfer and pressure drop of R-410a in flat aluminum multiport tubes.

Brazed heat exchangers with aluminum flat multi-port tubes are being used as condensers of residential air-conditioners. In this study, R-410A condensation tests were conducted in four multi-port tubes having a range of hydraulic diameter (0.78 < Dh < 0.95 mm). The test range covered the mass flux from 100 to 400 kg m-2s-1 and the heat flux at 3 kW m-2, which are typical operating conditions of residential air conditioners. Results showed that both the heat transfer coefficient and the pressure drop increased as the hydraulic diameter decreased. The effect of hydraulic diameter on condensation heat transfer was much larger than the predictions of existing correlations for the range of investigation. Comparison of the data with the correlations showed that some correlations reasonably predicted the heat transfer coefficient. However, most of the correlations highly overpredicted the pressure drop data.