Model Predictive Control of a Substation of a District Heating System for Enhanced Environmental and Economic Performance

This paper describes the design and optimization of the model-based predictive control (MPC) of a substation in the district heating system of the VUB campus. A properly controlled energy exchange improves the economy of the entire system while minimizing the pollutant emissions and fossil fuel consumption; the main goal of the European energy plan until 2030. The designed MPC modifies the flow rates in the substation, based on temperature evolutions and continuously provides an optimal return temperature in the network, while dispatching the desired amount of thermal power to the building. Compared to the installed proportional integral (PI) control, a reduction in substation return temperature of 10 °C can be obtained. The environmental and economic benefits of this reduced substation return temperature were assessed via a techno-economical model of the condensing boiler in the DHS, showing a 13% increase in overall efficiency, 11% of operational savings and a reduction of 5 ton in CO2 emissions, when compared with the experimental data of December 2020.