Thermal-mechanical Analysis on Foundation Schemes of Molten Salt Storage Tanks

Molten salt storage tanks are crucial for long-term and high-capacity thermal energy storage and electricity peak shifting. However, their foundation is vulnerable to structural damage from material overtemperature and large deformations under combined thermal and hydrostatic loads. In this work, steady-state and transient thermalmechanical behavior of non-cooled, air-cooled, and water-cooled foundation configurations are studied. The influence of high temperature on the structural response is analyzed. The result shows that thermal effects alter the deformation pattern especially at the edge of the foundation, and increase the maximum displacement from 105.0 mm to 125.5 mm. The investigations of steady-state air- and water-cooled cases show that the cooling tubes can effectively control and uniform the foundation temperature, particularly preventing the concrete overtemperature, while increasing the edge deformation, local stress concentration and maximum displacement. The influences of the environment temperature and cooling fluid velocity on the temperature and deformation are also investigated, and discussions between comparable air- and water-cooled cases have been made. Transient simulations of a 2-hour salt filling process and a 1-hour thermal storage process show that the average temperature of the upper layers rises following the variations of the molten salt temperature and level, and the foundation settlement increases with time. The structural response exhibits delayed thermal and mechanical equilibrium during thermal storage. The study also proposes three future research directions: improved foundation model, extended study scope, and artificial intelligence combination.