Simulation-driven design and optimisation of fifth-generation district heating and cooling networks integrated into renewable-based collaborative energy initiatives

• Novel design can simultaneously enhance dew-point efficiency and cooling capacity. • A quantitative study is conducted on the distribution of along-channel parameters. • Customized perforation can realize the reallocation of thermal and mass parameters. • A new dimensionless near-saturation evaluation index is introduced. • The regulation mechanisms of single and multi-parameter are revealed. Fifth-generation district heating and cooling (5GDHC) systems offer a key solution to accelerate the electrification of thermal demands in urban areas, promoting renewable integration and energy sharing. This study addresses the need for energy-flexible network designs that enhance efficiency by increasing thermal inertia and operational adaptability. Different layouts of 5GDHC systems are proposed and optimised, including a single-network design with water tank to increase network thermal inertia, and a single-network design with a water tank integrating solar technologies combined with power-to-heat/cool strategies. A dynamic simulation of a mixed-use district in Sorrento (Italy) including data centre waste heat recovery is carried out, supported by surrogate modelling to ensure scalability. Compared to a conventional two-network baseline systems (electricity consumption of 19.9 MWh for heating demands, and 95.7 MWh for cooling demands), a single-network design achieves global electricity savings of 20 %, increased up to 45 % when solar technologies are integrated. Power-to-heat/cool strategies boost solar self-consumption from 40 % to 84 %. The developed simulation tool is exploited to provide a surrogate model that maintains a 9 % deviation from detailed simulations. Using this surrogate modelling, the performance of the single-network design is assessed across various European climates (Almeria, Turin, and Freiburg) and district configurations, demonstrating optimal electricity savings of ∼22 %. These results demonstrate the viability and scalability of 5GDHC optimisation strategies, whereas this work introduces novel methods for their design and evaluation, supporting real-world implementation in diverse urban settings.