The importance of an accurate numerical model for the simulations of new generation district heating systems

• Published in: Journal of physics. Conference series 2024-11, Vol.2893 (1), p.12030
• Main Authors: Dénarié, Alice, Aprile, Marcello, Motta, Mario
• Format: Article
• Language: English
• Subjects: Accuracy; Alternative energy sources; Complex variables; Diffusion rate; District heating; Energy resources; Heating; Heating systems; Low temperature; Method of characteristics; Numerical models; Renewable energy sources; Renewable resources; Simulation models; Substations; Thermal simulation
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/2893/1/012030

The aim of this work is to present a fast and accurate district heating simulation tool conceived to support the implementation of successful integrations of renewable energy sources along district heating networks. New generation district heating systems are facing new challenges related to increasing integrations of distributed renewable energy sources and new type of customers, such as prosumers. These connections introduce a great variety of low temperature highly variables energy profiles in the network that traditional modelling tools cannot properly simulate. Therefore, a specific thermo-hydraulic simulation model has been built to simulate the complex dynamics of entire network and its components, combining accuracy and rapidity. The model uses different numerical approaches to properly taking into account the thermal inertia of the components capacity, namely the water network and the users. The rapidity and reduction of computational effort is reached by the use of a Lagrangian approach based on the method of characteristics applied to the piping elements. Compared with the commonly used finite-volume and the node method, the proposed model shows accurate results at a lower computational expense and reducing numerical diffusion and artificial smoothing. In order to properly simulate the effects of the user behaviour on energy demand, flow rates and return temperatures of the network, a simplified but accurate user substation model is built with a lumped capacity approach. The model accuracy is investigated under real operating conditions with one-year hourly monitoring data of an Italian district heating network.