Analytical design of decoupling control for variable flow hydronic heating system

Hydronic heating systems are used in homes and apartments worldwide. The variable flow system is advantaged to the energy saving while the control in variable flow system is difficult. This paper describes the typical variable flow hydronic heating system and presents the coupling mathematical model of heat exchanger. Based on the mathematical model, a new analytical design method of decoupling controller matrix is proposed in terms of the standard internal model control structure for variable flow hydronic heating system. Its advantage is that absolute decoupling for the nominal responses of system outputs can be implemented, and moreover, the controller parameters can be tuned on-line in a monotonous manner to cope with the perturbed plant dynamics, so that significant decoupling regulation can be achieved. The detailed simulation shows that the decoupling control system is effective and feasible.