Stress analysis of external molten salt receiver

Abstract

Commercial solar thermal power plant projects using central receivers with molten salt as a heat transfer fluid are dominating the market. Due to the complex load situation, especially the inhomogeneous heat flux distribution, the receiver components are subjected to complex thermo-mechanical loads. Transients from operation like clouds, start up and and shut down lead to fatigue of the components. Furthermore, the filling process could be critical due thermal gradients between salt and the metallic components. In this paper, a work flow is presented and results applied at the receiver of the Solar Two experiment to demonstrate the methodology. Thermal models (FE and CFD) are used to deduce the thermal field for different operational situations and a stress analysis is carried out. It was found that highest stresses occur at the absorber tubes for maximum flux density operation (inlet panel). The stresses caused by the filling process are much lower.