Cold energy storage as a solution for year-round renewable artificial ground freezing: Case study of the Giant Mine Remediation Project

In cold regions, passive thermosyphons are often employed in permafrost protection and artificial ground freezing (AGF) applications. While passive thermosyphons utilize available cold wind during cold seasons, energy-intensive refrigeration plants are sometimes needed to run thermosyphons in warmer seasons. In this study, a novel cold energy storage (CES) concept is proposed to operate thermosyphons year-round using renewable energy resources. The proposed system is based on additional energy storage ground coupled thermosyphons (ST) and heat extraction pipes (HEP). In cold seasons, the STs store wind cold energy, which is then transferred in warmer seasons using HEPs to the site of interest. The system is mathematically demonstrated using numerical models validated in our previous work against field data from the Giant Mine Remediation Project (GMRP). The results reveal that the proposed system enhances the heat extraction capacity of primary thermosyphons (located in the site of interest) by more than 15%. Further, the ground freezing process is achieved one year faster. Overall, this study presents the foundation of an innovative concept that can help run thermosyphons using renewable resources in cold regions, especially at the GMRP.