Engineering Aspects of a Parabolic Trough Collector Field with Direct Steam Generation and an Organic Rankine Cycle

Abstract

This thesis comprises engineering aspects of a parabolic trough collector field with direct steam generation and an organic Rankine cycle for a concentrating solar power plant to be erected in Tunis in 2015. The small scale power plant will have a nominal output of 60 kWel and will combine solar thermal power with a biogas boiler fed from local waste and will integrate a phase change material storage system. The plant is part of REELCOOP (Research Cooperation in Renewable Energy Technologies for Electricity Generation), a project funded by the Seventh Framework Programme of the European Union. The power plant is meant for demonstration and educational purposes. Due to the magnitude of the project, the thesis contains the pre-design of the plant such as the elaboration of layouts, defining instrumentation and dimensioning the piping system, the expansion tank and steam drum. In order to define the required pumps, a calculation of the pressure losses within the piping, bendings, valves, filters, etc. along the process has been carried out. A draft for future operation of the plant has been elaborated based on the results of an experimental campaign carried out at SOPRAN (solar process heat applications), a parabolic trough collector testing plant at the German Aerospace Centre. These experiences allowed to have a reference for a better understanding of the plant operation, including preparation, start-up, regular operation and shutdown procedures. The performance of the solar collector field and ORC for nominal and partial loads according to experimental data from the collectors and the ORC has been simulated with the software Greenius. Based on these results and meteorological data of Tunis, the annual electricity generation for a representative operation year has been calculated.