Optimal configuration of a solar-powered Organic Rankine Cycle power plant utilizing thermochemical energy storage

Abstract

The thermal energy storage system greatly influences the efficiency and design of the Organic Rankine Cycle (ORC) power plant. In this research, a novel thermochemical energy storage (TCES) system was incorporated into the solar energy-driven ORC system to enhance its overall efficiency. The study details the TCES system, which utilizes paired metal hydrides (specifically LaNi4.25Al0.75/LaNi5) in conjunction with a phase-change material (PCM). What makes this system unique is its integration with an ORC system-a novel approach not previously explored or examined. In order to evaluate and enhance the performance of the TCES system, an optimization model based on simulations was created using the SAM (System Advisor Model) software. This optimization framework is aimed at concurrently determining the best system design, taking into account factors such as solar multiple, storage duration, the levelized cost of electricity (LCOE), and the availability of solar resources at the location of the ORC plant. This study primarily focuses on achieving the best overall performance for a 50 MW ORC power plant in Tunisia. The results of this research demonstrate that the proposed ORC plant has the potential to generate an annual energy output of 244.2 GWh-e. This outcome is achieved through an optimized system design that incorporates a net conversion efficiency of 54.4 %, a solar multiple of 2.2, and a storage duration of 6.2 h. Additionally, the levelized cost of electricity (LCOE) decreases to a minimum value of 11.4 c/kWh. The study's findings emphasize the significance of integrating the TCES system into the ORC plant, driving advancements in solar energy technologies, and providing valuable insights for the development of future ORC plants.