Experimental investigation of all-regime control for supercritical CO2 Brayton cycle system

The Supercritical carbon dioxide (sCO2) Brayton cycles have garnered significant research attention due to their potential applications across diverse energy conversion systems. The development of effective control strategies constitutes a critical prerequisite for ensuring successful commercial implementation of this technology. However, the research on the control strategies primarily focuses on simulation, there have been limited experimental studies on system control, with a predominant focus on evaluating the efficacy of manual control logic rather than assessing the effectiveness of specific controllers within control strategies. Furthermore, most studies primarily concentrate on load following control and start-stop operations, overlooking critical aspects of extreme working conditions. This paper conducts experimental tests on all-regime control including load following, system start-stop, as well as emergency shutdowns in case of fault conditions. The results demonstrate that control accuracy exhibits strong dependence on both the linear relationship between operating variables and controlled parameters and the thermodynamic properties of the working fluid. Inventory control demonstrates relatively distinct efficiency superiority. The crux of maintaining safety subsequent to a system failure resides in depressurizing and cooling in a rational manner. The experimental tests on the control strategies offer significant references for the formal operation of the sCO2 Brayton cycle system.