Molten Salt for Parabolic Trough Applications: System Simulation and Scale Effects

Abstract The trend of solar thermal power plant engineering towards lower investment and energy costs leads to a demand for higher operating temperatures in the plant cycle. The use of molten salts withstanding temperatures up to 550 °C is considered for use in CSP plants, in particular for parabolic trough systems. In thermal storage systems fluids as “Solar Salt” (NaNO3/KNO3) are already state of the art. As the thermodynamic boundary conditions are completely different from those of plants utilizing thermal oil, the resulting changes in storage, collector and receiver design have a considerable impact on energy output and on the business case. Simulations carried out in cooperation of SCHOTT Solar CSP GmbH, schlaich bergermann und partner - sbp sonne gmbh and Flabeg GmbH show the effect of different plant layouts and operating conditions in terms of annual power generation, investment costs and LCoE. A comparison to power tower plants is made.