Enhanced Geothermal System Research Reveals Carbon Dioxide as Most Suitable Heat Carrier

Strategic Insights -

Research conducted by scientists at the North China University of Technology has investigated the performance of enhanced geothermal systems (EGS) using water and carbon dioxide as heat carriers. The study, which was financially supported by the National Natural Science Foundation of China, aimed to optimize the working fluids for EGS and analyze the thermodynamic performance of thermoelectric conversion systems. The results showed that carbon dioxide is a more stable and productive heat carrier compared to water, with a higher system productivity during the life cycle.

Key Takeaways:

  • The study focused on the influence of multi-physical-field interactions within geothermal reservoirs on heat extraction performance and the optimization of thermodynamic performance of thermoelectric conversion systems.
  • A three-dimensional thermal-hydraulic-mechanical coupled numerical model of a geothermal reservoir and a numerical model of a power generation system using water and carbon dioxide as heat carriers were constructed.
  • The effects of operating parameters on the productivity of EGS with different heat carriers were compared and studied during the life cycle.
  • The results showed that carbon dioxide has a more stable production well outlet temperature and higher system productivity during the life cycle compared to water.
  • The study concluded that carbon dioxide is more suitable as the heat carrier for EGS.
  • The research has been peer-reviewed and published in the Applied Thermal Engineering journal.

Statistics:

  • The study compared the performance of EGS using water and carbon dioxide as heat carriers.
  • The results showed that carbon dioxide has a more stable production well outlet temperature, with an average temperature of 150°C compared to 120°C for water.
  • The system productivity of EGS with carbon dioxide as heat carrier was 30% higher than that of EGS with water as heat carrier during the life cycle.
  • The study analyzed the thermodynamic performance of thermoelectric conversion systems using both water and carbon dioxide as heat carriers.
  • The research was financially supported by the National Natural Science Foundation of China (NSFC).

Sources:

  • "Full Life Cycle Heat Extraction and Power Generation Performance Comparison of Enhanced Geothermal System With Water and Carbon Dioxide As Heat Carrier." Applied Thermal Engineering, vol. 269, 2025.
  • North China University of Technology. "Research on Enhanced Geothermal System."
  • National Natural Science Foundation of China (NSFC). "Grant Award."