Simulation of transient behaviour in refrigeration plant pressure vessels: mathematical models and experimental validation

Four dynamic models of different degrees of complexity were derived to represent a typical industrial refrigeration intercooler (pressure vessel). The models were validated against temperature and pressure data from two pilot plant calorimeters containing R-134a under a variety of transient operating conditions. The measured response rate was strongly influenced by sensible heat storage in the calorimeter shell and liquid refrigerant. Little difference in predictions by the four models was obtained in spite of major simplifying assumptions made to develop the less complex models. A model considering only the thermal capacity in the shell and liquid refrigerant predicted rates of temperature change within 10% of predictions by the other models, and also close to experimental data.