Design and performance investigation of modified dual reflector parabolic trough collector with double planar mirrors

In a typical parabolic trough collector (PTC), sunlight is concentrated at the bottom of the absorber tube. This concentrated solar flux leads to uneven heat distribution, resulting in high local temperatures and significant thermal stress on the absorber tube. These limitations have restricted the application of PTCs in solar thermochemistry and other fields and have impacted their safe operation. In this study, a new PTC with dual planar mirrors (DPMS) is proposed to homogenize the circumferential solar flux distribution of the absorber tube. A design method and single-objective optimization of the new PTC with a DPMS are proposed, and an uncertainty analysis of the operational and structural parameters is performed. A coupled light-heat-structure numerical model was developed to study the heat transfer performance and structural mechanical properties. The thermodynamic properties of the PTC with DPMS under different boundary conditions were analyzed. The results show that the circumferential temperature difference of the new PTC is within 2.6 K, and the circumferential thermal deformation is within 0.9 mm under typical working conditions (the inlet velocity of the heat transfer fluid is 3 m/s, inlet temperature is 573.15 K, and the direct normal irradiance is 1000 W/m2). Compared with conventional PTCs, the circumferential temperature difference is reduced by 74%-90%, and the maximum thermal deformation along the y-axis is reduced by more than 95% under all working conditions (1-5 m/s, 373.5-675.15 K, 200-1000 W/m2). The new PTC maintains the uniformity of the circumferential solar flux distribution for different operating parameters (sun incident angle of 0 degrees-3 degrees) and installation errors (+/- 3 mm), is suitable for solar energy applications in various fields, and has the potential for large-scale applications.

Automated summary

This study proposes a new type of parabolic trough collector (PTC) with dual planar mirrors (DPMS) to homogenize the circumferential solar flux distribution. A design method and optimization approach are proposed, and an uncertainty analysis is conducted. The results show that the new PTC maintains low circumferential temperature difference and thermal deformation under different working conditions, making it suitable for solar energy applications in various fields and having the potential for large-scale applications.