Decrease of the energetic consumption in process control

Several indexes to compare the performance of automatic control systems applied to specific processes are shown in control theory literature. Nevertheless, crucial aspects like the energetic cost to eliminate the controlled variable deviation and the work done by the final control element, are neglected. In this work, different control strategies such as conventional proportionalintegral- derivative (PID) controllers, feed-forward control algorithms and internal model control techniques are compared. The comparison is made in an alimentary fluid heating process. The performance is measured by using the integral of the absolute value of the error, the settling time, the maximum deviation of the controlled variable, the work done by the final control element and the energetic cost associated with the manipulated variable. It is demonstrated how the additional control techniques can help to decrease the energetic operation costs. All the strategies can be implemented using typical industrial instrumentation.