3D CFD modelling of dust deposition characteristics and influences on building-mounted photovoltaic system

Abstract

Airborne dust deposition on the solar photovoltaic panels can significantly decrease the photovoltaic efficiency performance. Dust deposition characteristics and influences on building-integrated photovoltaic panels were studied by shear stress transfer k-ω turbulence model with inlet profiles and discrete particle model. The influences of dust size, wind velocity, and building roof inclination on the dust deposition behaviors were studied carefully. The air flow fields, the dust particle trajectories, the deposition rate on solar photovoltaic panels and the photovoltaic efficiency decrease by dust deposition were obtained and analyzed in the study. The three-dimensional simulation has great difference on the wind flow structures compared with two-dimensional simulation. The size of the separation vortex in the three-dimensional simulation is significantly smaller than that in two-dimensional simulation. The secondary flow structures become more significant in the rear of the building. The dust deposition rate is firstly increased and then decreased with the increasing of dust diameter. The maximum deposition rate is 2.54% for 150 μm particles. The minimum deposition rate is just 0.03% for 500 μm particles. The maximum deposition rate is 1.39%, 2.54% or 3.74% for the roof inclination angle of 16.7°, 22.6°or 36.9°, respectively. When particle size is 150 μm, the dust motions are determined by the air flow fields, mass inertia and gravitational settling. The photovoltaic efficiency reduction is significantly higher with increasing of dust size. The present model can conveniently estimate the photovoltaic efficiency decrease by dust deposition in realistic engineering application.

Keywords

• Dust deposition
• Solar photovoltaics
• Wind flow
• Building-integrated photovoltaics