A novel parabolic trough receiver enhanced by integrating a transparent aerogel and wing-like mirrors

In this paper, a novel evacuated receiver was proposed to improve the efficiency of the parabolic trough collector. In this receiver, a solar-transparent aerogel supported by a glass support was employed to insulate the absorber in the directly illumined vacuum zone, and wing-like mirrors on the support were designed to collect some irradiance wasted in the conventional receiver. An optical model developed using ray tracing and a heat transfer model developed using computational fluid dynamics were employed to study the receiver performance. Firstly, optical study indicates the receiver optical efficiency first increases then decreases with increasing aerogel thickness due to the combined effects of the aerogel and the mirrors. The peak receiver optical efficiency of 89.56% is achieved when the aerogel thickness is 20 mm. Moreover, thermal study indicates the receiver thermal efficiency just monotonically increases with increasing aerogel thickness before the aerogel touches the absorber. Then, the receiver with the aerogel thickness of 20 mm was selected as the suggested design after considering both the efficiencies and the safety requirements. Finally, performance evaluation reveals that the suggested receiver can improve the receiver efficiency at any direct normal irradiance or fluid temperature compared with the conventional receiver, which is the originality of this work. It is found the receiver efficiency can be improved by 0.32-5.04% under the typical direct normal irradiance of 300-1000 W.m(-2) and the inlet fluid temperature of 573-823 K. Results from present study are beneficial for improving the Yperformance of the parabolic trough collector.