Preliminary and robust design analysis of a solar thermal power block

Abstract

Australia is endeavouring to expand the mix of power resources, and is investing heavily in the development of renewable generation methods such as concentrated solar thermal power. In these systems, the power block and turbine need to maintain high efficiency under non-ideal conditions away from the design point. Literature shows that there is a clear relationship between the selection of fluids, the design of the operating cycle, the fluctuation in operating conditions and changes in power block performance. It is thus important for innovative power block designs to consider the performance of the system as a whole rather than by component, mainly turbine design, cycle development and economic analysis. However, there are few works that consider the coupling of multidisciplinary design and robust design to turbine-fluid selection and economic analysis for realistic systems. Furthermore, existing methodologies for robust optimisation often do not consider the effects of high-density gas properties on the performance of the power block. It is also critical that a power generation system produces ideal economic outcomes that meet a number of key performance indicators including levelised cost of electricity. Therefore, this paper develops a preliminary multidisciplinary design and robust design applied to turbine-fluid selection and economic analysis of a solar-thermal power block. In this work, an Organic Rankine Cycle using novel working fluids for a solar thermal power system is developed. Integrating robust optimisation into the development of the power block is key to push efficiency further and guarantee power block feasibility when running at non-ideal conditions. A preliminary multidisciplinary optimisation is applied to design the complete power block concept such that the power block operates at peak performance across multiple analysis approaches. When using a multidisciplinary design approach, it is possible to perform robust optimisation on the whole power block where the target is on the economic outcomes rather than traditional targets such as efficiency, specific power generation capacity or size.