Physical Model of District Heating Networks to Boost the Transition to Next-Generation Systems

District heating networks are key players in the decarbonization of urban energy systems. A detailed understanding of their thermo-fluid dynamic behavior is required to address their evolving operating conditions, such as lower temperature supply, increasing integration of storage and renewable energy sources, and the interconnection with the electricity grid. In this scenario, the development and application of simulation models to estimate the distribution and evolution of pressures, mass-flow rates, and temperatures along the networks is becoming increasingly important. In this work, a physical simulation model is proposed. This allows replicating the operation of the network under varying operating conditions, making it possible to simulate potential future scenarios. The compactness of the model allows large-scale networks to be simulated without excessive computational effort. Moreover, a compact simulation setup allows the simulation model to be incorporated into optimization frameworks, which are essential in a transition context where a large number of changes have to be tested and implemented. The methodology is applied to a real large-scale district heating network, providing insights into the thermo-fluid dynamics of the network and enabling the assessment of system responses under varying boundary conditions. The results highlight how physically accurate and computationally efficient simulation tools can facilitate the transition towards more sustainable energy systems.