A novel perspective of addressing the hydraulic dynamic imbalance in district heating network: The application of nonlinear programming

Hydraulic balance within the heating system's pipeline network is essential for efficient operation. Hydraulic imbalances can result in increased energy consumption and heat loss. Accordingly, a new dynamic hydraulic model has been developed, leveraging the topological structure of the network. This model incorporates the nonlinear constraints associated with flow coupling between electric valves and variable frequency pumps, with the objective of minimizing energy used in pump operation. It determines the optimal pump frequency and valve settings for operational adjustments. The model's predictive accuracy was validated using real operational data from a campus heating system. Additionally, it calculates the campus's ideal load and evaluates the potential for energy savings. Three adjustment strategies were established based on different temporal scales: hourly, day-and-night, and daily. Findings indicate that the optimized system offers substantial energy savings, particularly the hourly adjustment, which reduces pump energy consumption by 38.2 % and total system flow by 9.0 %. The day-and-night variable frequency was the next most effective, reducing pump energy consumption by 32.8 %, and total system flow by 7.6 %. The daily variable frequency strategy showed the least energy savings, with pump energy consumption by 25.0 %, and total system flow by 5.5 %. This dynamic hydraulic regulation optimization model serves as a valuable tool for developing intelligent heating systems.