Continuous/discrete simulation of controlled atmosphere (CA) cool storage systems: model development and validation using pilot plant CA cool storage H.B. Nahor a, * , N. Scheerlinck a , P. Verboven a , J. Van Impe b , B.M. Nicolaı ¨ a a Flanders Center/Laboratory of Postharvest Technology, Department of Agro-Engineering and Economics, Katholieke Universiteit Leuven, W. de Croylaan 42, B-3001 Leuven, Belgium b Bioprocess Technology and Control, Department of Chemical Engineering, Katholieke Universiteit Leuven, W. de Croylaan 46, B-3001 Leuven, Belgium Received 15 December 2003; received in revised form 23 March 2004; accepted 16 April 2004 Abstract Simulation of dynamic processes in controlled atmosphere (CA) cool room storage systems has been developed. The model consists of three interacting sub-models for the prediction of the transient behavior of the processes in the three units, namely, the cool room, the refrigeration system and the gas-handling unit. Several modules representing each of the components in these units were developed based on energy and mass balances. The modules were then arranged to form the sub-models, which were interconnected, in turn, into the global CA cool storage system model. The modules were implemented in an object-oriented computational environment, (EcosimPro) which can handle both continuous and discrete events. The model was validated using experimental data from a pilot plant CA cool storage facility. Model predictions of the most important discrete and continuous processes were found to agree to the experimental data with a maximum difference less than the observed spatial variability or at best with the accuracy level as set by the measurement instruments. As product respiration and quality models are incorporated, it is possible to use the model for optimization of plant performance with respect to the final quality of the stored product. Moreover, the handling of discrete/continuous events enables the implementation of practical operational procedures and to investigate their implication directly on the product quality and plant performance/design. Published by Elsevier Ltd on behalf of IIR. Keywords: Cold storage; Controlled atmosphere; Modelling; Transient regime; Optimization; Performance Entreposage sous atmosphe `re contro ˆle ´e: simulation en continu, de ´veloppement et validation d’un mode `le a ` partir d’une installation pilote Mots-cle ´s: Entreposage frigorifique; Atmosphe `re contro ˆle ´e; Mode ´lisation; Re ´gime transitoire; Optimisation; Performance 1. Introduction Nowadays, controlled atmosphere (CA) storage systems are widely employed for the storage of a wide range of International Journal of Refrigeration 27 (2004) 884–894 www.elsevier.com/locate/ijrefrig 0140-7007/$ - see front matter Published by Elsevier Ltd on behalf of IIR. doi:10.1016/j.ijrefrig.2004.04.011 * Corresponding author. Tel.: þ32-16-32-26-68; fax: þ 32-16- 32-29-55. E-mail address: nahor.haddish@agr.kuleuven.ac.be (H.B. Nahor).