A new thermodynamic modeling method for Brayton cycle schemes based on heat flux of the heat source

The supercritical carbon dioxide Brayton cycle is a promising option for power generation. However, the existing models for assessing its performance lack universality for various layouts and rely on challenging-to-acquire thermodynamic parameters at state points (such as the inlet temperature of the turbine). The present study proposes a modular thermodynamic modeling method, making it suitable for various layouts. A parameter-matching method is proposed using the heat flux of the heat source as an input, making it more practical than methods relying on parameters at state points. The method's accuracy is verified with a deviation not exceeding ±1.5%. Subsequently, four typical schemes including simple recuperation, recompression, intercooling, and reheating cycles are analyzed. The effect of heat flux on power generation and thermal efficiency of each scheme is also evaluated. It is found that the simple recuperation cycle is capable of operating effectively within lower thresholds for both maximum pressure and temperature. For maximizing power generation, the intercooling cycle offers an advantage. As for thermal efficiency, the simple recuperation cycle is best suited for heat fluxes under 1.6 MW/m2, while the recompression cycle is recommended for fluxes exceeding this limit. The outcomes can guide the designing and optimization of Brayton cycle schemes.