Model Predictive Control of Distributed Adjustable Jet Pump in District Heating System Considering Renewable Energy Access

High energy consumption of the pipe network and low user comfort are long-standing problems in district heating systems. In order to address these challenges, this paper proposes a dynamic operation control method for district heating systems based on distributed adjustable jet pumps. While taking advantage of traditional jet pumps to balance hydraulic power, the area ratio of the adjustable jet pump can be dynamically adjusted by the controller to adapt its operating characteristics to current heating needs. In this paper, the mechanism modeling of the adjustable jet pump is firstly carried out. Then jet pump models are distributed and combined with the farthest, middle, and nearest heat user models to form the entire control system. Subsequently, a multiple-input and multiple-output model predictive control method is designed, which considers both the physical constraints of adjustable jet pumps and the disturbance of renewable energy output. Finally, taking a district heating system in Beijing as an example, the room temperature comfort and energy-saving benefits under MPC, PID, and non-control conditions were compared and analyzed. The calculation results show that the room temperature comfort under MPC controller has the greatest improvement. Moreover, compared to PID control, it can save 5.8% of the circulating pump power consumption, and 10.0% compared to non-control condition.