Improved Frequency Domain Modeling of Dynamic Heat Flow for DHS Energy Flow Calculation

With the extensive interconnection and deep coupling of electricity and diversified energy carriers, traditional energy networks are increasingly evolving into integrated energy systems. While energy flow modeling and power flow calculation, as foundational aspects of energy system analysis, have established mature computational models and methods across various energy sectors, current approaches relying on time-domain nodal methods and finite difference schemes lack unified modeling strategies. This limitation introduces excessive spatiotemporal discretization elements during practical computations, resulting in compromised computational efficiency and potential inaccuracies in power flow solutions. This paper proposes a frequency-domain modeling framework for district heating systems (DHS) that refines the existing energy circuit model (ECM) theory, adaptable to both constant-flow and variable-flow operational scenarios. Derived from mass conservation principles, the methodology incorporates scaling transformations for fluid element dynamics and thermal loss corrections. The developed model achieves high precision while significantly enhancing computational performance, demonstrating particular advantages in handling complex DHS network analyses.