Modeling of a Microchannel Condenser using Volume-of-Fluid (VOF) Computational Fluid Dynamic (CFD) Simulations for Heat Pumps

The current industry standard for best-practices in the modeling of heat pump components is to use zero- and one-dimensional simulations to model and optimize heat pumps. There is an opportunity to further understand the performance of these components in extreme environments, such as cold climate operation, a task which is well-suited for utilizing detailed computational fluid dynamic (CFD) simulations to model and optimize the performance of heat pump components. A simplified parallel square micro-channel is modeled to investigate the condensation of Fluorinet FC-72. Qualitative flow map regimes, as well as quantitative data in the form of pressure-drop and heat-transfer coefficients, are utilized from experimental results for validation of the model setup. The liquid mass fraction measured at the outlet is dependent on the mass flow rate at the inlet, as well as the spatial boundary conditions for the heat flux on the side walls of the condenser. Results are shown for different operating conditions that correspond to different flow map regimes, as well as the effect of refrigerant properties on condenser performance. Long-term utilization of the CFD simulations to improve reduced-order models for system-level components for heat pumps are presented.