Performance optimization of larger-aperture parabolic trough concentrator solar power station using multi-stage heating technology

The large-aperture parabolic trough concentrator (PTC) solar power can reduce the initial investment and in-crease the outlet temperature. However, the use of a single absorber tube (AT) cannot meet the requirements of maximize efficiency and the outlet temperature of 580 degrees C. Therefore, a multi-stage heating technology is pro-posed to improve the efficiency and outlet temperature in this study. The single-loop, consisting of a semi-circular AT with two outer fins, a semi-circular and circular AT, makes the temperature rise from 300 degrees C to 580 degrees C. The results show an optical efficiency of 79.1% and a thermal efficiency of 72.8%, for a 1400 m single -loop and a mass flow of 6.1-19.9 kg/s (corresponding to DNI of 400-100 W/m2). The large-aperture multi-stage PTC solar power established in Dunhuang, China (E 94.66, N 40.14) has an annual average solar-to-electric efficiency of 24.50%, higher than 20% at present. At the same time, homogenizing the solar radiation flux at the AT surface at the high-temperature section can reduce the length of the high-temperature region and increase the thermal efficiency, and the solar-to-electric efficiency of a large-aperture multi-stage PTC solar power can be increased by improving the thermal efficiency and the exit temperature.