Control-Oriented Modeling of Transcritical Vapor Compression Systems
Alleyne, Andrew G.
vapor compressor systems
This thesis details the efforts to develop a dynamic model of a transcritical vapor compression system
suitable for multivariable control design purposes. The modeling approach is described and the developed models
are validated with experimental data. The models are nonlinear, independent of fluid type, and based on first
principles. Linearized versions of the nonlinear models are presented. Analysis of the linearized models and
empirical models created using system identification techniques suggest that lower order models are adequate for the
prediction of dominant system dynamics. Singular perturbation techniques are used to justify model reduction.
Based on the reduced order models, the dominant dynamics of these systems are identified and described in terms of
physical phenomena. Although all results presented are for a transcritical vapor compression cycle with carbon
dioxide as the working fluid, the methodology and results can be extended to both subcritical and transcritical
Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.