Defence of dissertation in the field of Control Engineering, M.Sc. (Tech.) Philipp Nguyen
The title of thesis is “Modelling, estimation and control of waste heat recovery and desalination processes in maritime applications”
In maritime applications the energy-efficient operation of ships has benefited from waste heat recovery systems that enhance the extraction of thermal energy within the system that would have dissipated otherwise, e.g. exhaust gas, coolant. However, the occurrence of process uncertainties such as incomplete models, unobserved states, disturbances potentially leads to performance deterioration or system instability in the worst case. Here, the focus lies on two particular systems, namely a freshwater cooling circuit and a multistage flash evaporation plant.
The thesis presents a method when the unobserved waste recovery process is successfully stabilized in the presence of unknown drifting parameters. Furthermore, the closed-loop system is proven to be conditionally Gaussian with optimal mean-square state estimates for the FWC-circuit on hand. A stochastic PDE model has been developed for the desalination processes inside the MSF plant that is corrupted by the effects of flow turbulence. Efficient water production is ensured by stabilizing the pressure head inside the subdomain to a reference profile by means of boundary controls. The applied controls are sufficiently robust as the induced error field is kept within tight bounds.
The obtained results can be utilized in enhancing grey box identification methods as well as application in the control of PDE systems
Opponent: Professor Kurt-Erik Häggblom, Åbo Akademi University, Finland
Supervisor: Professor Arto Visala, Aalto University School of Electrical Engineering, Department of Electrical Engineering and Automation.