Dynamic Modeling of a Parabolic Trough Solar Power Plant

Models for dynamic simulation of a parabolic trough concentrating solar power plant were developed in Modelica for the simulation software Dymola. The parabolic trough power plant has a two-­‐tank indirect thermal storage with solar salt for the ability to dispatch electric power later in the evening and during the night when little or no solar irradiation is present. The complete system consists of models for incoming solar irradiation, a parabolic trough collector field, thermal storage and a simplified Rankine cycle. A parabolic trough power plant named Andasol located in Aldeire y La Calahorra, Spain, is chosen as a reference system when the complete system model is designed and built in Dymola. The system model is later validated against performance numbers from this reference system in order to make sure a correct implementation has been made. The collector and solar model have also been validated against different papers regarding solar collector performance and show good results. Finally the system in Dymola has been simulated during a day for different parts of the year with solar data from the same region as the Andasol power plant. The results from these simulations show similarities to how the Andasol power plant operates and how well the system performs under different solar irradiance conditions. By modeling the system dynamically the changes in insolation over time can be studied to gain information about how it affects the system model in detail. Plant startup time and how long the system can be running on the thermal storage is other parameters that could be studied with this dynamic model.