Photovoltaic thermal system design including aquifer thermal energy storage in a fifth generation district heating network in Hilversum

The urgent need to address global warming and transition to sustainable energy solutions has driven the development of innovative heating systems. Among those solutions, several district heating alternatives have been proposed to combine heat pumps and thermal energy storage tanks. This paper addresses the integration of photovoltaic thermal systems (PVT) with aquifer thermal energy storage (ATES) within a fifth-generation district heating network as an innovative combination to minimise electrical power consumption from the grid, thereby reducing grid dependency and CO2 emissions. The proposed configuration is tested for the Werfgebied district in Hilversum, the Netherlands A Python model of the multi-energy carrier system is developed to investigate the effects of configuration, storage distribution, and component sizing within the district heating network, embedding the thermal and electrical behaviour of the components and their interaction. The results show that an optimal configuration for the ATES and PVT combination involves a single ATES well rather than distributed thermal energy storage. The results indicate that the aquifer's size significantly affects the overall operating temperature and its fluctuations. A larger ATES maintains a stable but relatively colder temperature. If constrained by a maximum allowed ATES temperature of 20 °C, the optimal ATES size is 175 000 m3; however, when considering the overall benefit and excluding that constraint, the optimal system size comprises an ATES of 380 000 m3 and an 800 module PVT system, reducing the overall emissions by 856 tonnes of CO2 equivalent compared to the case without the district heating.