The influence of wind and module tilt on the operating temperature of single-axis trackers

We measure the module temperature T-\{m\} in 1P and 2P single-axis trackers, analyzing how T-\{m\} depends on wind speed and direction, as well as on irradiance, ambient temperature and module tilt ß. On a clear day, we find that the typical temperature variation within a tracker is 1-4°C for 1P and 2-6 °C for 2P trackers, where the coolest region tends to be nearest the torque tube. Whether for 1P or 2P, we find that when ß < 25°, the wind cools the windward side of the tracker by 1-1.5 °C more than the leeward side; but when ß > 25°, the upper side is 0.5-1.5 °C cooler than the lower side, irrespective of wind direction (for wind speeds < 5 m/s), We also find that the commonly used NOCT and Faiman temperature models overpredict T-\{m\} by, on average, 7.4 °C and 3.3 °C. Even after calibrating these models to our trackers, they only predict T-\{m\} at any given time to ±6.6 °C with 95% confidence. Without adding any free variables, the modelling accuracy is improved to ±3.8 °C by accounting for radiative loss to the sky and transient effects; the accuracy is improved further to ±2.8 °C by accounting for module tilt, wind direction and ground temperature. This study expands upon the PV industry's understanding of how single-axis trackers are influenced by wind speed, wind direction, and tilt, and it refines our ability to accurately predict T-\{m\} of FTC's Voyager 2P tracker.

PV Lighthouse, FTC Solar

Keith R. McIntosh and Malcolm D. Abbott and Ben A. Sudbury and Saurabh Aneja and Mitch Bowman and Lance Brown and Ben Kahane and Norm Nicholas and Kristian Nolde

2022

10.1109/PVSC48317.2022.9938577

01608371

Conference Record of the IEEE Photovoltaic Specialists Conference

2022-June