Heat Transfer and Entropy Generation Evaluation on Molten Salt Tank Foundation with Internal Water Cooling

Abstract

Molten salt tanks are used to store and release thermal energy. Large heat leakage through the molten salt tank foundation to the ground and high temperature of the foundation are detrimental to long-term operation safety. Here we evaluate the heat transfer and entropy generation characteristics of molten salt tank foundations with internal water cooling. Both laminar and turbulent flows reduce the heat leakage efficiently, while the power consumption for the laminar flow is negligible. The effects of the geometrical parameters are presented. Internal fins in the cooling channels decrease the heat leakage significantly. The total entropy generation rate with foundation cooling is higher than that without foundation cooling. The entropy generation rate in the solid domain is much larger than that in the fluid domain and the flow friction irreversibility is tiny. Larger insulation layer thickness decreases the heat leakage and the total entropy generation rate simultaneously. The local entropy generation rate map helps us identify where the most irreversibility is produced. The largest local entropy generation rate for the design with foundation cooling occurs near the solid-fluid interfaces and is much higher than that without foundation cooling.