Kharitonov-Hurwitz Based Optimal Control Law for a Heat Exchanger System Using Constraints on Maximum Closed-loop Amplitude Ratio

A cascade control law employing non-linear constraint optimization for a shell and tube heat exchanger system is presented in this paper. Shell and tube heat exchangers are widely used in various industries for efficient heat transfer between two fluids. The control of such systems is crucial to ensure optimal operation and maximize energy efficiency. Hence, the main aim of the work is to regulate the shell outlet temperature. The cascade control structure employs an inner loop with a PI controller to regulate the flow rate, whereas a PID controller is employed in the outer loop to maintain the desired temperature. Further, a separate flow controller is used to govern the flow rate. The design criteria arc attained with the control law by minimizing the error. The intended specifications are attained by imposing constraints on bandwidth and loop-gain. Further, the performance of the controller is analyzed with external disturbances and parameter uncertainties. Besides, the Kharitonov-Hurwitz theorem is used to determine the robust stability. The findings highlight the potential of the proposed technique in achieving optimal control of shell and tube heat exchanger systems. The proposed control strategy offers a practical approach to improving temperature regulation and energy efficiency, contributing to industrial processes’ overall performance and sustainability.