Application of un-fired closed Brayton cycle with mass flow regulation and particles-based thermal energy storage systems for CSP

In this work it is evaluated the performance of regenerative closed Brayton power cycle for Concentrating Solar Power (CSP) applications. Power plant components and operation control strategy have been designed in order to fully cover electricity demand of the grid to which it is connected in Sicily (Italy). Results analysis is proving that pure solar Brayton cycle can follow electricity demand curve during most of the day through base pressure and mass flow regulation of the closed-loop and the introduction of particles-based Thermal Energy Storage (TES) system between solar receiver and turbine. Operation flexibility and non-expensive price of the working fluid (air) and storage medium (particles) make this concept very attractive for CSP applications. Detail analysis of the results is showing that the selected 20-MW power block can produce around 42 GWh per year, and when TES is included the power plant operation will increase from 3393 hours to 4640 hours, which represents an increase of 53 % working time