Vapor compression cycle systems using accumulators and receivers inherently operate at or near a transition point involving changes of phase at the heat exchanger outlets. This work introduces a condenser/receiver model and an evaporator/accumulator model developed in the moving-boundary framework. These models use a novel extension of physical variable definitions to account for variations in refrigerant exit phase. System-level model validation results, which demonstrate the validity of the new models, are presented. The model accuracy is improved by recognizing the sensitivity of the models to refrigerant mass flow rate. The approach developed and the validated models provide a valuable tool for dynamic analysis and control design for vapor compression cycle systems.

This paper presents experimental validation of a dynamic vapor compression cycle (VCC) system model specifically suited for multivariable control design. A moving-boundary lumped parameter modeling approach captures the essential two-phase fluid dynamics while remaining sufficiently tractable to be a useful tool for designing low-order controllers. This research makes two key contributions to the control-oriented dynamic modeling of these systems. First, the moving-boundary approach is used to develop models of evaporators and condensers with receivers, models previously unavailable in the literature. Second, semi-empirical correlations are incorporated for predicting key model parameters. The resulting models are compared to experimental data for validation purposes.

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