Water Gas Heater Non-Linear Physical Model: Optimization with Genetic Algorithms

J. Vieira and A. Mota (Portugal)


Non-Linear Physical Modelling, Genetic Algorithms, Time-Delay Estimation, Smith Predictive Control, Non Linear Control and Water Temperature Control.


This paper presents the steps taken for the semi-physical model construction of a domestic water gas heater. The water gas heater presents a large and varying time-delay and measured perturbations in water flow, cold water temperature and output water temperature. It is presented a detailed description of the water gas heater in terms of its physical characteristics and mathematical equations. The semi-physical model is implemented based on energy conservation equations and for the determination of some unknown parameters genetic algorithms were used. The accuracy and robustness of the implemented model was tested using a model based controller. The Smith Predictive Model Controller was used as an efficient controller for systems that present large and varying time delays. The real action control results using the Semi Physical Model based Smith Predictor Controller is presented showing the accuracy and robustness of the semi-physical model.

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