Parametric analysis of transient thermal and mechanical performance for a thermosiphon-concrete thermal energy storage system

An innovative thermosiphon-concrete thermal energy storage system is developed using an enhanced concrete formulation for sensible storage media and thermosiphons for heat exchangers. A finite element analysis approach is established for this cylindrically shaped thermosiphon-concrete thermal energy storage system to assess transient thermal and mechanical performance at different scales and under different operating conditions. Two modules at 10 kWh th and 150 kWh th capacities are modeled and validated against experimental data generated in previous studies by the authors. Parametric evaluation is then conducted to examine their thermo-mechanical performance with variations in charging/discharging rate, module geometry (slenderness ratio), type of concrete media, and type of heat transfer fluid. The validated simulation approach is demonstrated as an effective numerical tool to provide design guidance for the implementation of the proposed system or other similar thermal energy storage systems. • A simplified simulation approach for modeling thermosiphon-concrete TES system • A 10 kWh th module and a 150 kWh th TC-TES module are analyzed and used for validation. • Both thermal performance and mechanical performance during charging and discharging are assessed. • The slenderness ratio, media type and HTF condition are investigated in the parametric study.