In-tube performance evaluation of an air-cooled condenser with liquid-vapor separator

摘要

This study evaluates the thermal hydraulic performance of a novel liquid-vapor separation condenser (LSC). A series of experiments was performed to investigate the in-tube heat transfer coefficient and pressure drop of the LSC with varying average refrigerant quality at constant mass flux. The results were compared with the performance of a serpentine condenser (SC) and a parallel-flow condenser (PFC), with R134a as the refrigerant. Findings showed a very small change in the wall temperature of the LSC. The LSC had the lowest average condensation heat transfer coefficient among the three condensers at lower heat flux, but exceeded that of the PFC at higher heat flux. The pressure drop of the LSC was 77.1-81.4% lower than that of the SC and 57.5-64.6% lower than that of the PFC at a heat flux of 6.45 kWm~(-2). Moreover, heat flux and condensing temperature had little influence on the pressure drop of the LSC. Based on these experimental data, the three evaluation criteria (friction power ratio, penalty factor, and minimum entropy generation number) applied to the three condensers proved that the LSC had the best thermal hydraulic performance. The lowest irreversibility of the LSC resulted from the entropy generation rate of the refrigerant side, which was the lowest among the three condensers.