Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Civil and Environmental Engineering

Supervisor(s)

Dr. Horia Hangan

Abstract

A combination of Computational Fluid Dynamics (CFD) simulations and wind tunnel experiments are carried out to investigate the effects of wind on the aerodynamic loading and heat transfer of a ground mounted stand-alone photovoltaic (PV) panel with tilt angle of 25o in open country atmospheric boundary layer. Several azimuthal wind directions are considered: Southern 0o, Southwest 45o, Northwest 135o and Northern 180o. Three dimensional Reynolds-Averaged Navier-Stokes (RANS) approaches with an unsteady solver using Shear Stress Transport (SST) k-ω turbulence closure are employed for the CFD simulations, whereas Particle Image Velocimetry (PIV) and Hot Wire Anemometry (HWA) methods are applied for the wind tunnel experiments. The mean wind flow fields obtained from PIV and CFD for the stand-alone PV system are compared and an overall reasonable agreement is found. Further on, the same CFD simulation approaches are employed to evaluate aerodynamic loading of an array of ground mounted PV panels.

For the stand-alone PV system, maximum mean uplift is observed for 180o wind direction and maximum overturning moment for 45o and 135o wind directions. For 135o and 180o wind directions, higher level of turbulence on the leeward side of the panel are noticed based on the PIV experiment. Employing Hot Wire Anemometry, a weak shedding of vortices from the leading edge is detected only for the 180o wind direction. For the array configuration, all trailing rows are completely in the wake of the first windward row for 0o and 180o wind directions, which results in lower mean wind loads (drag, lift and overturning moments) on the trailing rows. Higher overturning moments are found for all rows for 45o and 135o wind directions cases. From the heat transfer simulation for the stand-alone system, dominance of natural convection over forced convection is observed for Reynolds number of 1.0x105. A correlation between dimensionless convective heat transfer coefficient, Nusselt number and Reynolds number is established for 0o and 180o wind directions. This work provides a new and in-depth analysis of surface pressures and heat transfer rates correlated to the flow field around ground mounted PV panels.