Thermodynamic analysis and optimization of liquid air power plant integrated with parabolic trough solar collectors

As to investigate the impact of parabolic trough collector optical characteristics on the comprehensive performance of solar-driven liquid-gas energy storage power plants, this study establishes a mathematical analysis model for a liquid-gas energy storage power plant with a parabolic trough collector. The effects of direct irradiance, collector tracking mode, and component configuration on collector efficiency, round-trip efficiency, and exergy efficiency are analyzed. The results show that when the direct irradiance exceeds 400 W/m2, the round-trip efficiency of the system decreases while the exergy efficiency increases. For every 100 W/m2 increase in irradiance, the round-trip efficiency decreases by 1.54%, and the exergy efficiency increases by 2.36%. The north-south axis tracking mode is superior to the east-west axis tracking mode and dual-axis tracking mode. The component configuration improves the collector efficiency and round-trip efficiency but decreases the thermal efficiency. In low irradiance conditions (direct irradiance less than or equal to 400 W/m2), the system performance is optimal when the collector optical efficiency is maintained at 74%. Under these conditions, the system achieves a maximum net energy output of 495.12 kW center dot s/kg, the exergy efficiency of 54.5%, and the round-trip efficiency of 18.96%. In high irradiance conditions (direct irradiance greater than 400 W/m2), a 10% increase in collector optical efficiency leads to a 1.94 kW center dot s/kg decrease in net energy output, a 3.14% decrease in exergy efficiency, and a 0.05% decrease in round-trip efficiency.