Road solar collector and borehole thermal energy storage integration into a district heating network in Italy

A promising solution to lower the energy consumption and greenhouse gas emissions due to building heating and cooling lies in the implementation of low-temperature District Heating Networks, collecting heat from diverse sources (solar thermal collectors, energy geostructures waste heat from industrial pro-cesses), store it underground during summer, and distribute via pipelines in win-ter. The REHEAT project examines the technical, social, economic, and legislative feasibility of such systems in Italian urban environments, with a focus on Padova, which aspires to achieve climate neutrality by 2030. The project has analyzed and modeled a small-scale network, beginning with a comprehensive review of existing Borehole Thermal Energy Storage to identify optimal designs considering underground conditions. Experiments were conducted to evaluate the efficiency of Road solar Thermal Collectors installed within parking lot pavements as ther-mal energy source. Finally, the functioning of a borehole thermal energy storage charged by a Road solar Thermal Collector satisfying the thermal requirements of a multiplex Cinema has been developed on a FEFLOW software fem model to evaluate the ground thermal evolution during the charging and discharging periods. Finally, all the DHN components are combined in a TRNSYS software model, to analyze the system behavior in a dynamic system-level simulation envi-ronment. The REHEAT project aims to advance sustainable heating solutions and contribute to achieving urban net-zero emission goals, also developing the local legal framework as well as the economic and social aspects.