Simulation of transient behaviour in refrigeration plant pressure vessels: mathematical models and experimental validation S. Estrada-Flores a, *, D.J. Cleland b , A.C. Cleland c , R.W. James d a Supply Chain Innovation, Food Science Australia, PO Box 52, North Ryde, NSW 1670, Australia b Institute of Technology and Engineering, Massey University, Palmerston North, New Zealand c The Institution of Professional Engineers New Zealand. PO Box 12241, Wellington, New Zealand d School of Engineering Systems & Design, South Bank University, 103 Borough Rd, London SE1 0AA, UK Received 11 April 2002; accepted 19 August 2002 Abstract 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 predic- tions by the four models was obtained in spite of major simplifying assumptions made to develop the less complex models.Amodelconsideringonlythethermalcapacityintheshellandliquidrefrigerantpredictedratesoftemperature change within 10% of predictions by the other models, and also close to experimental data. # 2003 Elsevier Science Ltd and IIR. All rights reserved. Keywords: Refrigerating circuit; Pressure vessel; Transient state; Operating; Modelling; Measurement Simulation du comportement transitoire des re´cipients sous pression des installations frigorifiques : mode´les mathe´matiques et validation expe´rimentale Mots cle ´s : Circuit frigorifique ; Re´servoir sous pression ; Regime transitoire ; Fonctionnement ; Mode´lisation ; Mesure 1. Introduction Pressure vessels such as intercoolers, receivers and surge drums are often used in refrigeration plants. The transients of parameters such as pressures, temperatures and refrigerant mass distribution in such vessels can be usedasindicatorsoftheoverallperformanceofaplant. Complex dynamic phenomena, such as de-superheating of vapour from low stage compressor, flashing of high pressure liquid and the heat flow from external (ambi- ent) conditions occur in such vessels (Fig.1). Two approaches have been traditionally used for developing vessel models: a) detailed models with time 0140-7007/03/$20.00 # 2003 Elsevier Science Ltd and IIR. All rights reserved. PII: S0140-7007(02)00081-6 International Journal of Refrigeration 26 (2003) 170–179 www.elsevier.com/locate/ijrefrig * Corresponding author. E-mail address: silvia.estrada-flores@csiro.au (S. Estrada- Flores).