The Long-Term Mitigating Effect of Horizontal Ground-Source Heat Exchangers on Permafrost Thaw Settlement

• Main Authors: Amir Fatollahzadeh Gheisari, Pooneh Maghoul, Hartmut M. Holländer, Rob Kenyon, Rob Sinclair, Maryam Saaly
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: Processes
• Subjects: geothermal heat exchangers; permafrost; thaw settlement; sustainability
• Online Access: https://www.mdpi.com/2227-9717/9/9/1636

This study investigated the long-term effect of horizontal Ground-Source Heat Exchangers (GSHEs) on mitigating permafrost thaw settlement. In the conceptual system, a fan coil was used to chill the recirculating fluid in the linear High-Density Polyethylene (HDPE) ground loop system. A fully coupled thermo-hydro-mechanical finite element framework was employed to analyze multiphysics processes involved in the thaw settlement phenomenon. To investigate the sustainability of the system, a period of 50 years was simulated. Two operational modes were defined: one without and the other with HDPE. Different heat carrier velocities and inlet temperatures, and heat exchanger depths were examined to explore their effects on the thaw settlement rate. It was concluded that the proposed system can effectively alleviate the predicted permafrost thaw settlement over the study period. Moreover, the heat carrier temperature was found to have a prominent impact on the thaw settlement rate amongst other parameters.