Design of tray tunnels for food deep chilling

A mathematical model for the semi-batch operation of tray tunnels for food deep chilling is presented and analyzed. Design aspects are discussed invol ving both single tunnels and systems of parallel tunnels. In both cases, op timum flowsheet configuration and operating conditions are sought and verif ied by appropriate formulation of design and optimization strategies. The o ptimization objective is the total annual cost of the plant, subject to con straints imposed by the operation of the chilling tunnel, thermodynamics an d construction. The decision variables were the number of trucks, the opera ting temperature and flowrate of the cooling air stream, the refrigeration cycle heat exchanger temperature, as well as the total number of sections i nvolved. The Mixed-Integer Non-Linear Programming (MINLP) nature of the des ign problem required mathematical programming techniques for its solution. The optimization was carried out for a wide range of production capacities, and the optimal points, where a new truck or a new section is introduced, were evaluated. The analysis focused on the design of tray tunnels for the most popular food product treated by deep chilling meat slabs. A characteri stic case study is presented in order to demonstrate the effectiveness of t he proposed approach. (C) 1999 Elsevier Science Ltd. All rights reserved.