Experimental study on micro-channel condenser with header-orifice liquid-vapor separator in domestic refrigerators.

The liquid-vapor separation process enhances heat exchanger performance by improving the refrigerant phase distribution, leading to an improved heat transfer coefficient and reduced pressure drop. While many solutions exist for achieving liquid-vapor separation, the header-orifice structure emerges as one of the most cost-effective solutions, particularly in compact parallel flow condensers. This study extends the application of the header-orifice to parallel flow micro-channel condensers in domestic refrigerators using isobutane, which operate at notably low refrigerant flow rates of approximately 0.3 g/s - 0.5 g/s. Experimental results demonstrated that the orifice location can influence liquid-vapor separation, especially when the gas entrainment cannot be ignored. The tube-side orifice condenser can reduce pressure drop by 1.1 kPa and 2.1 kPa at mass flow rate of 0.3 g/s and 0.5 g/s, respectively. Furthermore, videos demonstrated that the tube-side orifice promoted liquid accumulation, and the header-side orifice caused more gas infiltration.