Impact of pipe resistance on performance of supercritical carbon dioxide Brayton cycle system

Abstract

This study develops a system simulation model based on the megawatt-class supercritical carbon dioxide Brayton cycle unit in Hengshui, China, to examine the effect of pipe section resistance on system performance. The results indicate that increased pressure loss in pipe sections significantly reduces power generation efficiency and power supply efficiency. Specifically, a 100 % increase in pressure loss results in 3.290 % and 4.377 % decreases in power generation efficiency and power supply efficiency, respectively. Moreover, higher pressure loss leads to increased CO2 mass flow rate at design power generation load. When the pressure loss is doubled, it requires a 17.593 % increase in CO2 mass flow rate to achieve the design power. Pressure loss in high-pressure section has minimal impact on system performance, while resistance in low-pressure section significantly affects it. For instance, a 100 % increase in pressure loss from the compressor outlet to the low temperature regenerator inlet causes a 0.37 % decrease in system power supply efficiency, and a similar increase from the high temperature regenerator outlet to the low temperature regenerator inlet leads to a 0.76 % decrease. These findings provide meaningful guidance for component design and piping layout optimization for similar systems.

Keywords

• Supercritical carbon dioxide
• Brayton cycle
• Pipe resistance
• System performance
• Exergy loss