Designing a Safe and Optimal Heat Storage System in Salt Caverns for Maximum Thermal Efficiency and Heat Output

Abstract

This thesis addresses the central research question: "How can operational and structural parameters be optimized within salt caverns to enhance thermal efficiency and safety for heat storage?" Focusing on the Twente region, this study employs COMSOL Multiphysics and DIANA FEA software for a comprehensive analysis. COMSOL is used to evaluate the influence of operational parameters such as temperature differentials (ΔT), initial temperatures, and the impact of cavern shape and aspect ratios on the thermal performance and efficiency of salt caverns used for energy storage. DIANA FEA conducts geomechanical analyses to assess the structural safety and stability of these caverns. Simulation results from COMSOL indicate that higher ΔTs and initial temperatures enhance rapid heat absorption, which may lead to quicker energy depletion, suggesting a balance is crucial between heat retention and extraction. Adjustments in cavern shape and aspect ratios were found to significantly influence thermal efficiency, highlighting the potential for geometric optimization in storage effectiveness. The geomechanical analysis via DIANA FEA provides essential insights into managing subsidence and internal pressures, critical for ensuring the structural safety of these storage systems. This contributes to advancing theoretical knowledge and offering practical strategies for efficient and safe thermal energy storage implementations . Given the scarcity of research on utilizing salt caverns for thermal energy storage, this study not only fills a significant gap in the literature but also demonstrates the potential for further detailed investigation. The findings suggest promising areas for enhancing the efficiency and safety of these storage systems, thereby contributing to the diversification and sustainability of energy storage solution.