Optimization of a Microchannel Condenser with Separation Circuitry

Abstract Experiments in the past proved that separation of vapor and liquid was beneficial for a condenser prototype with a specific separation circuitry. The prototype elaborated had the inlet in the middle of the height and separates into two flow paths downstream of the second header. The two paths recombined upstream of the subcooling pass of the condenser. This paper first explains the trade-off between the capacity in the upper passes and the lower passes, based on an experimentally validated steady-state condenser model built in a previous study by the same authors. The condenser model incorporates a mechanistic model for the second header to calculate the separation efficiency. Then, this paper presents a search for the optimal design of a microchannel condenser with the separation circuitry (separation condenser) using R134a. Parameters are optimized on pass circuitry, fin density, and air velocity distribution. An order for the tube number of each pass, in general, is given for the optimal pass circuitry. After the optimization, the separation condenser shows a 17.8 % improvement in the mass flow rate of R134a compared to a conventional condenser with the same total airside area.