Transient Modeling and Sensitivity Analysis of a Controlled R744 Swash Plate Compressor

19^th International Compressor Engineering Conference at Purdue

The focus of this investigation is the development of an advanced transient model to describe the operation of a controlled swash plate compressor for an automotive air-conditioning system using the natural refrigerant R744. The over-all model consists of several partial models, that describe the thermodynamic laws in the control volumes of the cylinders, the suction and discharge chamber as well as the crankcase, the heat transfer, the dynamics and friction of the swash plate and the pistons, the valve behavior, the piston leakage and the control valve mass flows. Based on measured data from the literature a validation is carried out under stationary full load operation conditions. The main focus of this investigation and the achieved progress compared to the state-of-the-art are the simulative linkage of the sub models in one complete model: the dynamic modeling of pistons and swash plate taking into account the impact of each individual piston on each other. An extensive sensitivity analysis was carried out to achieve a better understanding of the over-all compressor model behavior. Based on this analysis, the model and geometric parameters with a significant impact on the main model's variables and efficiencies were identified in each sub model. A subsequent goal is the generation of a compressor characteristic to provide compressor efficiencies for cycle simulations.