integrated accumulator and internal heat exchanger, oil distribution, component optimization for reversible systems
Carbon dioxide is one of the most promising next-generation refrigerants for air-conditioning applications in electric vehicles because it has the advantages of good heating performance in cold climates and environmental-friendly properties. Nonetheless, there are limited data about reversible CO2 heat pump systems for component-level performance and design. This paper focuses on the impact of different sizes of oil bleed hole on the liquid level and local pressure drop in the accumulator through CFD simulation. Also, we applied the experimental data obtained with a full CO2 HP system for the boundary conditions and the measured properties of liquid POE-CO2 for the materials in the simulation. The cases with different sizes of the oil bleed hole are investigated using the commercial computational fluid dynamics software Fluent. The results of this paper can be used to design the accumulator and improve 1-D models for reversible systems so that it can operate well in both air-conditioning and heat pump modes.