Modelling of a prosumer’s substation in a district heating network: validation and dynamic analysis

Thermal grids will play a key role in the development of local energy communities and the achievement of 100% renewable societies. However, challenges are related to the capability of dealing with the increasing number of producers which could supply heat to thermal grids. Indeed, as in the case of the electricity grid, heat could be available for some hours in a day from RES plants installed at user level and distributed in the network (also referred to as “prosumers”). To achieve more reliable results when performing energy analyses of these innovative applications, there is a need to rely on accurate models of each component. For instance, substations are of paramount importance in the interaction of prosumers with thermal grids. These systems must properly exchange heat with the network according to the prosumer demand and production while complying with grid constraints. In this respect, there is a need to develop models of prosumers’ substation, which accounts for technical details (e.g., connections, heat exchangers, valves, etc.) and controls. Starting from the layout of a bidirectional substation for a thermal energy network proposed in the literature, this paper proposes a dynamic model that replicates the experimental setup in the TRNSYS environment. Simulations are performed to validate the model. The results show a good matching between experimental and simulated results in terms of dynamic behavior and energy balance. To show the capabilities of the proposed model, a prosumer with heat available from solar thermal collectors installed onsite is considered as a case study. Results show that almost 13.8% of the heat produced by the prosumers is exchanged with the grid. It is worth noting that the validated TRNSYS model will support studies on the feasibility of Thermal Energy Communities in existing systems, to develop strategies for energy-efficient and cost-effective operation and monitoring the performance.