Optimization capacity configurations and operational regulation methods of the heat source with passive heat storage in district heating systems

Operational optimization of district heating systems (DHSs) with its own thermal inertia has been regarded as an effective approach for energy conservation. This kind of approach usually relies on advanced optimization algorithms, but the complexity of these algorithms makes it very challenging for their utilizations in practical engineering. To simplify and facilitate the use of the thermal inertia in DHSs, this study developed a novel passive heat storage (PHS) method to optimize the capacity configurations of heat sources and the operational regulations of DHSs. The key feature of the PHS method was its ability to harness the thermal inertia of DHSs while meeting real-time heat demands of end users. Furthermore, to accurately utilize the thermal inertia of DHSs, a heat storage quantification method and a heat storage state definition method were also developed. Moreover, operational performance of the PHS mode were also compared with the regular mode in terms of capacity configurations and operational regulations in an actual DHS. In addition, key factors affecting capacity configurations of the PHS mode were analyzed, in which a heat load-delay time distribution graph was proposed to illustrate the coupling effects between heat load distribution and delay times. Results showed that the utilization of the PHS method in DHSs could reduce the required heat source capacity effectively and improve operational efficiency and stability of DHSs. Additionally, the heat storage capacity quantification and state definition methods offered more precise and comprehensive assessments of the heat storage characteristics of DHSs.