Object-Oriented Modeling of a Multi-Pass Shell-and-Tube Heat Exchanger and its Application to Performance Evaluation∗

Molten salt thermal storage systems are the keystone of the dispatchability of demand in solar thermal power plants and many commercial plants use this technology. Nevertheless, there are still open questions related to long-term durability and reliability of components. During experimental campaigns in the CIEMAT-PSA molten salt testing facility, a performance detriment in a multi-pass shell-and-tube heat exchanger was noticed. For this reason and as a tool for analysis and diagnosis, an object-oriented dynamic model is being developed. This paper describes the testing facility and the thermal oil -molten salt heat exchanger particularly, the design of the Modelica model and compares simulation results against manufacturer calculations and experimental data in steady-state operation conditions and at transients in order to evaluate the heat exchanger performance.