Hydraulic-thermal coupling dynamic models based on mechanism and data-driven methods of the heating networks in integrated energy systems

Abstract

The district heating is expected to play a crucial role in the decarbonization of integrated energy systems within the context of attaining carbon neutrality. The literature review reveals a research gapin the investigation of models that account for thehydraulic-thermalcouplingdynamiccharacteristics of heating networks in integrated energy systems, particularly those based on the flow-regulation mode. This discrepancy may affect the safety of the heating networksand contribute to the inefficient scheduling of integrated energy systems, which motivates this study. In this study, it refutes the harsh hypotheses in previous studies, making it more closely related to the real hydraulic and thermal conditions of heating networks. A mechanism-driven model is proposed, which involves the coupled hydraulic and thermal dynamic characteristics of heating networks. The modified forward–backward iteration as a calculation method is carried out, which is embedded with the method of characteristic and upwind difference. A data-driven hydraulic-thermal dynamic model is proposed for fast calculations. For model validation and case analysis, three heating networks in the integrated energy systems are utilized. The simulation results indicate that1) The hydraulic and thermal average relative errors between the measured data and the simulation results are 0.396% and 0.091%, respectively, validating the effectiveness of the proposed dynamic mechanism model; 2) Compared to the current quasi-dynamic model, the proposed dynamic mechanism modelcould reflect the characteristics of heating networks more accurately and simulates the dynamic processes with higher resolution. These results demonstrate that the fluctuations of water head and pipe flow can reach 61.24 ∼ 237.53 m and −4.26 ∼ 32.16 kg/s, respectively. The average temperature difference between the two models is around 0.264 °C; 3) Compared to the forward–backward iteration, the modified forward–backward iteration has a superior convergence performance and calculation accuracy; 4) Compared to the quasi-dynamic model, the proposed data-driven model increases the overall accuracy of hydraulic-thermal calculations and significantly reduces the amount of time required. The average calculation time of the data-driven model is 0.0349 s, while those of the quasi-dynamic model and the proposed mechanism model are 352.92 s and 624.13 s, respectively. In conclusion, the proposed mechanism model of hydraulic-thermal coupling calculation and the related data-driven model are suitable for the dynamic simulations of heating networks in integrated energy systems.