Multi-objective thermodynamic optimisation of supercritical CO2 Brayton cycles integrated with solar central receivers

In this paper, optimisation of the supercritical CO2 Brayton cycles integrated with a solar receiver, which provides heat input to the cycle, was performed. Four S-CO2 Brayton cycle configurations were analysed and optimum operating conditions were obtained by using a multi-objective thermodynamic optimisation. Four different sets, each including two objective parameters, were considered individually. The individual multi-objective optimisation was performed by using Non-dominated Sorting Genetic Algorithm. The effect of reheating, solar receiver pressure drop and cycle parameters on the overall exergy and cycle thermal efficiency was analysed. The results showed that, for all configurations, the overall exergy efficiency of the solarised systems achieved at maximum value between 700 degrees C and 750 degrees C and the optimum value is adversely affected by the solar receiver pressure drop. In addition, the optimum cycle high pressure was in the range of 24.2-25.9 MPa, depending on the configurations and reheat condition.