Prediction of process parameters for intelligent control of tunnel freezers using simulation

Various analytical and empirical methods assuming the existence of steady state and requiring homogenous properties of the product have been used with limited success in estimating freezing times in the food processing industry. Irrespective of the method adopted for estimating freezing time requirements, a critical process issue that needs to be considered is that of system control. Simulation models suggest that a feed-forward control strategy, as discussed in this paper, can be used to control a freezing tunnel and obtain considerable energy savings while ensuring 'appropriate' freezing of all products. The control strategy discussed in this paper, involves the continuous monitoring of product input and controlling either or both of the refrigerant flow and conveyor speed. The primary objective of this paper is to demonstrate the use of simulation to predict process parameters for 'intelligent control' of freezing tunnels, and provide an estimate of potential energy savings.