Thermally induced tank stress in a single tank

Abstract

Single-tank thermocline-based molten salt storage systems present a cost-effective alternative to conventional two-tank configurations in concentrating solar power (CSP) plants. However, the structural integrity of large-scale single tanks remains a key design challenge due to thermal and mechanical stresses. This study investigates the critical diameter for single-tank molten salt storage by performing a comprehensive parametric analysis of structural constraints. Various design parameters, including tank height-to-diameter ratio, insulation strategies, material properties, and thermal gradients, are evaluated to determine their impact on mechanical stability. Finite element modelling and analytical methods are used to assess stress distributions and deformation limits under operational conditions. The results indicate that beyond a specific diameter threshold, structural reinforcements become imperative to prevent excessive mechanical stresses, thereby influencing both economic and operational feasibility. It is also shown, that there is a physical limit of the tank diameter beyond which technical realization becomes impossible. These findings provide crucial insights for optimizing large-scale thermal storage tanks in next-generation CSP plants.