In the face of climate change and the imperative to reduce greenhouse gas emissions, harnessing geothermal energy for mitigating environmental impact and curbing global warming stands as a promising solution. The increasing reliance on intermittent renewable energy resources necessitates effective energy storage solutions for both electricity and heat. Underground reservoirs provide a substantial avenue for heat storage, predominantly achieved through Aquifer Thermal Energy Storage (ATES) systems. Interestingly, the widespread adoption of ATES remains limited, with the Netherlands hosting nearly 90% of global ATES installations. Furthermore, the majority of existing ATES systems predominantly store low-temperature heat (below 30°C). Enhancing their efficiency and energy density hinges on the storage of higher-temperature water during warm seasons for subsequent heat recovery in colder periods.