Mathematical modeling and control of thermal plant in the district heating system of Korea

The development of a mechanistic model for the thermal plant in the district heating system is addressed. Energy balance is composed of the change of enthalpy and the generation of the heat by a fuel combustor, on the basis of several assumptions. Effective thermal capacitance is estimated using the data measured in the heating system of Su-Seo area in Korea, and the validity of the developed model is clearly shown by the comparison of outlet temperatures from the boiler between the model prediction and data measured during the period other than that for the estimation. The model performs satisfactorily, and its usefulness has been illustrated by the application of the model-based controller for the regulation of outlet temperature. The controlled case shows that the temperature is maintained close to the set-point, and the energy saving is expected to be about 10 million USD for a year in the area.