MultiEnergySystem: A Modelica Library for Dynamic Modeling and Simulation of District Heating and Gas Networks

Abstract

This paper presents the MultiEnergySystem Library (MESL),an open-source Modelica library designed for the dynamicsimulation of integrated district heating and gas/hydrogennetworks. MESL introduces a fully equation-based fluidproperty formulation, ensuring model interpretability andenabling compatibility with control and optimizationapplications. The library includes dedicated models forhydrogen blending studies and supports gas qualityindicators such as Wobbe Index (WI), Higher Heating Value(HHV), and Specific Gravity (SG). District heating modelshave been experimentally validated using data from areal-world test facility, and these datasets are providedto support reproducibility. While MESL currently focuses onthermal and gas domains, planned expansions include a morecomprehensive electrical package and experimentalvalidation of hydrogen components. The paper describes thelibrary’s design and validation strategy, concluding withillustrative case studies and ongoing development plans.