Flow Characteristics in a Microchannel Condensers With Extraction Circuitry

The present study reveals the characteristics of refrigerant flow in a microchannel condenser with the extraction circuitry. The extraction circuitry provides a potential to enhance the condenser performance at almost no cost – the condenser geometry is the same except for a few well-sized drainage holes in the header baffle. A microchannel condenser is modified to run in both the extraction mode and the conventional mode. A 1-D finite-volume model is built for the condenser and is validated with R134a experimental data. The capacities agree within ±5 % and the pressure drops agree within ± 25 %. Using this model, a numerical study is conducted on the condenser. A singleextraction-tube design and a double-extraction-tube design for the extraction mode are both simulated and compared. The flow characteristics in the extraction tube are revealed for a physically possible range of liquid separation efficiency. The effects of flow resistance in the extraction tube on the phase separation efficiency and the condenser performance are also studied.