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ABSTRACT: Ice-based thermal energy storage systems, utilizing both sensible and latent heat capacities of water, have achieved successful commercialization and are currently operational in numerous installations worldwide. However, conventional chilled water and ice-based energy storage systems often necessitate substantial space to store significant quantities of cooling energy. To address this limitation, the subsurface emerges as a promising solution. Nevertheless, the freezing of the ground introduces potential alterations in its behavior, leading to changes in pore pressure and ground movement. In this study, the TOUGH multiphase flow code was enhanced by incorporating water/ice phase change capabilities and subsequently validated against analytical and experimental data. Our investigation focused on the subsurface as a potential storage site for ice, taking into account the impact of ground permeability, spacing between freezing pipes, freeze/thaw damage, and refrigerant temperature. Numerical simulations using a Thermo-Hydro-Mechanical approach were conducted over a 10-year period, representing 10 cycles of seasonal freeze/thaw, to comprehensively assess the performance and long-term stability of a generic subsurface ice storage system. 1 INTRODUCTION Amid the global push for sustainable energy solutions, the reliability of renewable sources like solar and wind power is undeniable. However, their intermittent nature highlights the urgent need for efficient energy storage to balance clean energy supply and demand. This paper focuses on addressing the demand for cooling in hot regions, driven by rising temperatures due to climate change. Among various energy storage technologies, ice thermal storage has shown promise for building cooling at a district scale (Chan et al., 2006; Gang et al., 2016). This method typically involves chilling a glycol solution, circulating it through coils immersed in a water tank to freeze the water during off-peak hours, and then thawing the ice for cooling during peak hours. Despite the proven effectiveness of ice thermal storage, challenges arise when integrating renewable energy sources into the freezing process, particularly in urban areas due to space constraints (Yan et al., 2016). To address these challenges, this study explores the concept of subsurface ice-based thermal energy storage. This innovative approach involves installing underground freeze pipes through which a glycol solution circulates, allowing the ground to freeze in winter and extracting the stored cold energy for air conditioning in summer.
Tounsi et al. (Sun,) studied this question.