Comparison of different load-following control strategies of a sCO2 Brayton cycle under full load range

Abstract

The supercritical CO2 Brayton cycle has been regarded as a promising next-generation power conversion system owing to its flexibility and high efficiency. Dynamic performance and control strategy are essential research topics when systems are subjected to various load demands. Inventory control has been proven as a very effective load control method and valve controls have the potential to meet wider load demands. While few studies have focused on the differences in efficiency and system performance under different control strategies. In this study, a dynamic model of recompression supercritical CO2 Brayton cycle is proposed, and its components are carefully validated. Moreover, an inventory and anti-surge coupled control strategy is proposed to achieve better control performance. Under the premise of considering system security, various control strategies meeting 0%–100% load range are compared. The primary objective of this study is to reveal the differences in efficiency and dynamic performance of various control strategies in the full load range, to provide a basis for the selection of control strategies in off-design conditions. The results demonstrate that inventory and anti-surge coupled control allow safe tracking loads as low as 0%, and it provided an absolute advantage in terms of efficiency compared to valve controls.