Performance and design optimization of single-axis multi-position sun-tracking PV panels: Fid-Bau Portal

Performance and design optimization of single-axis multi-position sun-tracking PV panels

Li, Guihua / Chen, Yingbo / Yu, Yamei / Tang, Runsheng / Mawire, Ashmore

In this article, the photovoltaic (PV) and sun-tracking performance of single-axis multiposition sun-tracking PV panels (MP-PV) is investigated based on solar geometry and dependence of PV conversion efficiency on the incident angle of solar rays on PV panels. For such PV systems, the azimuth angle of the PV panels is adjusted daily M times from an eastward direction in the morning to a westward direction in the afternoon by rotating the PV panels about the inclined north–south axis (INSA) to ensure that the projected incident angle (PIA) of solar rays on the plane perpendicular to the INSA is always less than the angle θ_a, the specified maximum PIA. Results show that the annual average sun-tracking efficiency ( $η_{s t}$ ) and the annual electricity generation (AEG) of the MP-PV system increase as M increases, but this increase is less than 1% when M > 5. The optimal θ_a of the MP-PV system for maximizing AEG and the ratio (C_p,MP-0) of AEG of the optimized MP-PV system to that of a similar fixed PV system are highly dependent on the annual average atmospheric clearness index (K_t) but only slightly dependent on the site latitude (λ). For an MP-PV with a tilt angle (β) of the INSA that is fixed yearly, the AEG of 3P-, 5P-, and 7P-PV systems is about 92%, 94%, and 95%, respectively, of that obtained from a similar dual-axis tracking PV panel (2A-PV). However, for an MP-PV whose β is adjusted four times a year at three tilts, the AEG of 3P-, 5P-, and 7P-PV systems is about 96%, 98%, and 99%, respectively, of that of a similar 2A-PV system. Empirical correlations for quick estimation of the optimal θ_a and C_p,MP-0 of the MP-PV optimized for maximizing AEG are suggested and examined based on monthly global radiation on the horizon at 30 sites around China.