Energy assessment of a district by integrating solar thermal in district heating network: a dynamic analysis approach

This work focuses on the energy upgrade of a neighbourhood located in Yverdon-les-Bains, Switzerland. Starting from a potential low-temperature district heating network, the possible integration of new buildings equipped with solar thermal collectors capable of interacting with the network is explored. The methodology proposed in this work focuses on the study of the energy balance of the district at reduced time intervals. Bringing the level of detail to every single hour of the year, the concept of energy balance is superseded by the hourly averaged power balance as a specific tool for a detailed exploration of the energy flows exchanged within the district. Self-sufficiency has also been identified as key performance indicators to better understand the ability of the entire district to satisfy its heating and domestic hot water needs, modelled in CitySim's urban energy environment. The outcomes have shown that an annual energy balance is ineffective and unrealistic for describing performances of the district. On the other hand, the hourly averaged power balance proves to be a powerful tool for understanding the dynamics of the neighbourhood. The district's energy flexibility, which relies on energy sharing, is a characteristic that cannot be assessed annually. Using the new proposed methodology to evaluate the district's thermal energy sharing, it was discovered that the district functions as a Zero Energy District for 28.9% of the year. With the outcomes presented in this study, it is now possible to comprehend how a dynamic performance assessment positively impacts a district's redevelopment strategies.