I am currently developing a large and complex thermo-hydraulic systems in Modelica/Dymola environment using ThermoPower library by Prof. Francesco Casella. At present, I have completed building our system model (which contains several closed-loop hydraulic circuits) and concentrating on designing controllers for the developed model. Given complexity of the system, I have about 25 PI controllers controlling various valve opening, pump, condenser and boilers. At this stage, I am tuning the controller gains using some judicious trial-and-error method. I tried to look into literature to see if there are any formal design methodology or any rule-of-thumbs for designing controllers for such a multi-input-multi-output (MIMO) thermo-hydraulic system. Consequently, I would like to ask if anyone can provide some pointers or literature/papers which deals with controller designs for such systems. Because my knowledge in controller design (sliding mode, linear control, root locus, etc) are not helping me here as most of these methodology are based on available model equations.

Furthermore, for such a large thermo-hydraulic systems, how one sets initial conditions of the system? Does one need to just provide some reasonable guess value and expect Dymola to take care of rest of it?

I apologize if you have seen this question somewhere else.

Thanks

JG