Solar tracker error impact on linear absorbers efficiency in parabolic trough collector – Optical and thermodynamic study

Abstract

The parabolic-trough solar concentrating systems are often considered element of heat generation systems from renewable energy sources. It is important to use appropriate optical systems and solar trackers because parabolic trough collectors utilize only direct solar radiation. The paper presents the results of an analysis of the effect of solar tracker error on the optical and thermodynamic efficiency of linear absorbers. The results are presented for low concentrated geometry, popular among scientific institutions, consistent with the existing facility operating under natural conditions. Two diameters of the linear receiver were considered in the analysis: 33.7 mm and 21.3 mm. The research was carried out in optical engineering software based on the Monte Carlo ray-tracing method. Thermodynamic analysis was performed based on the mathematical model of the radiation absorption phenomenon by heat transfer fluid. The maximum angle error of the solar tracker for the tested geometry, not significantly affecting the performance of the linear absorber for a diameter of 33.7 mm is 1.5°, and for 21.3 mm is 0.9°. The reduction in efficiency for 2° error is 4.7% points, and 42.5% points respectively. The analysis also presents the results of the radiation distribution on the surface of the absorber tube.