Operation optimization of district heating systems considering dynamic thermal characteristics and passive heat storage

Utilizing thermal inertia in district heating systems (DHSs) for operation optimization is widely regarded as an effective strategy for energy conservation. However, this approach often entails a trade-off by compromising indoor thermal comfort, as it disrupts by disrupting the real-time balance between heat outputs from heat sources and heat loads of end-users. To leverage the heat storage potential of the DHSs while maintaining the real-time balance, this study introduced a passive heat storage method based on the dynamic thermal characteristics of the DHSs. An operation optimization model was then established to optimize the operational regulation of the DHSs by integrating the dynamic thermal characteristic of the DHSs with the proposed passive heat storage method. And a simulated annealing algorithm was employed to solve the resulting multi-objective optimization problem. Additionally, to evaluate the effectiveness of the passive heat storage method over an entire heating season, a monthly multi-characteristic day temperature method was proposed to capture the temporal variation of outdoor temperatures throughout the entire heating season. Simulation results based on an actual DHS demonstrated that, without additional investment, the proposed optimization method can reduce operational energy consumption and circulation pump costs by approximately 27.36%, decrease carbon dioxide emissions by about 1083.19 tons, and significantly improve heating quality for end users over the heating season.