Experimental Study on Heat Transfer Performance and Pressure Drop of Microchannel Condenser with Liquid Separation

The size and location of the separating holes at low mass flow rates (<1 g/s) have a significant impact on the performance of condensers with liquid separation. The heat transfer performance and pressure drop of R600a in five microchannel condensers with liquid separation were studied experimentally. Additionally, the heat transfer performance and pressure drop characteristics of the five liquid separation condensers under different refrigerant mass flows, inlet air temperatures and velocities, and condensing pressures were analyzed. According to the experimental results, the heat-exchange performance of the condenser with liquid separation orifice at the second baffle was better than that at the third baffle. As the mass flow rate of the refrigerant increased, the refrigerant-side pressure drop in the liquid separation condenser decreased significantly. When the refrigerant mass flow rate was 0.60 g/s and 0.40 g/s, the refrigerant-side pressure drop of the condenser with liquid separation orifice on the second baffle was 21.28% and 17.29% lower, respectively, than that of the baseline condenser without liquid separation. The performances of the liquid separation condensers with different orifice diameters were compared using the comprehensive evaluation factor PEF. The average PEF value of the liquid separation condenser with an orifice size of 1.2 mm was 1.58. This was the highest among all the liquid separation condensers and yielded the best comprehensive performance.