Modeling, simulation and optimization of a beer pasteurization tunnel

This paper introduces a general computational model for beer pasteurization tunnels, which could be applied for any pasteurization tunnel in the food industry. A simplified physical model, which combines fundamental and empirical correlations, and principles of classical thermodynamics, and heat transfer, is developed and the resulting three-dimensional differential equations are discretized in space using a three-dimensional cell centered finite volume scheme. Therefore, the combination of the proposed simplified physical model with the adopted finite volume scheme for the numerical discretization of the differential equations is called a volume element model, VEM [Vargas, J. V. C., Stanescu, G., Florea, R., & Campos, M. C. (2001). A numerical model to predict the thermal and psychrometric response of electronic packages. ASME Journal of Electronic Packaging 123(3), 200–210]. The numerical results of the model were validated by direct comparison with actual temperature experimental data, measured with a mobile temperature recorder traveling within such a tunnel at a brewery company. Next, an optimization study was conducted with the experimentally validated and adjusted mathematical model, determining the optimal geometry for minimum energy consumption by the tunnel, identifying, as a physical constraint, the total tunnel volume (or mass of material). A parametric analysis investigated the optimized system response to the variation of total tunnel volume, inlet water temperature, production rate, pipe diameter and insulation layer thickness, from the energetic point of view. It was shown that the optimum tunnel length found is robust with respect to the variation of total tunnel volume, combining quality of the final product with minimum energy consumption. The proposed methodology is shown to allow a coarse converged mesh through the experimental validation of numerical results, therefore combining numerical accuracy with low computational time. As a result, the model is expected to be a useful tool for simulation, design, and optimization of pasteurization tunnels. 2005 Elsevier Ltd. All rights reserved.