Sustainable Process Systems Modeling of a Geothermal Powered Direct Air Capture and District Heating Concept

The global shift toward low-carbon and sustainable energy marks a critical step in advancing decarbonization and resilient energy systems. This study presents a process-to-system modeling of a geothermal energy integrated with direct air capture (DAC) and district heating systems. The designed geothermal-DAC-district heating configuration demonstrates a technically robust and thermodynamically synergistic pathway toward carbon-negative energy systems. By effectively integrating geothermal power generation with an all-electric DAC and heat recovery system, this designed configuration advances deep decarbonization goals and aligns directly with the United Nations Sustainable Development Goals (SGDs) on affordable clean energy, sustainable cities, and climate action. The analysis indicates that the turbine output and DAC performance are highly sensitive to geothermal operating parameters, suggesting that maximizing CO₂ capture efficiency requires operation at low flashing pressures and elevated reservoir pressures to ensure stable turbine performance and uninterrupted DAC operation. Employing the operational results obtained from the sensitivity analyses and parametric studies, the designed configuration captures 666.6 tCO₂ per year employing 8 DAC units and provides district heating to 124 households. The findings reveal that geothermal-DAC integration enables continuous, zero-emission CO₂ removal using renewable baseload energy while supporting community-scale heating demands, positioning the system as a viable technological pathway toward carbon neutrality and a sustainable energy infrastructure.