Performance analysis, optimization and dynamic control of a PTC-driven recompression sCO2 brayton cycle

This study develops a thermo-economic model for a parabolic trough collector (PTC)-driven recompression supercritical carbon dioxide (sCO 2 ) Brayton cycle equipped with printed-circuit heat exchangers (PCHEs). The model combines optical and thermal analysis of the PTC field, separate 40-segment calculations for the high- and low-temperature recuperators, multi-objective optimization, dynamic response analysis and constrained operating control. Under the reference condition, the system produces 576.27 kW of net power, with a Brayton cycle efficiency of 30.83%, a collector efficiency of 68.23% and a solar-to-power efficiency of 21.03%. The required heat-transfer areas of the two recuperators are 16.43 and 12.09 m 2 , with corresponding pressure drops of 102.34 and 101.87 kPa. The parametric analysis indicates that receiver temperature governs the balance between useful solar heat and thermal loss, whereas mass-flow allocation and recuperator performance control heat-capacity-rate matching and external heat demand. Increasing turbine-inlet temperature therefore improves the power cycle but does not continuously improve plant-level efficiency because radiative heat loss rises rapidly at high receiver temperatures. The net-power–investment Pareto formulation selects a 245.51 kW design with an investment of USD 3.82 million, while the composite thermal-economic formulation selects 539.56 kW, a system efficiency of 24.10%, an investment of USD 5.15 million and a levelized cost of electricity of 0.3192 USD/kWh. Component response times are calculated from thermal-capacitance and inventory balances rather than assigned as fixed constants. During a simultaneous 20% load reduction and 22% decrease in direct normal irradiance, the turbine-inlet temperature remains between 508.08 and 577.25 °C, while the maximum power tracking error reaches 96.46 kW after the collector reaches full focus. The residual power deficit arises from insufficient solar heat, indicating the operating range in which thermal storage or auxiliary heating is required.