Experimental investigation of dust deposition reduction on solar cell covering glass by different self-cleaning coatings

Dust deposition on the solar photovoltaic (PV) modules would greatly decrease the spectral transmittance of the covering glass and result in a significant reduction of PV output efficiency. In this paper, the dust deposition reduction on solar cell covering glass by different self-cleaning coatings was investigated by experimental measurement. Four glass samples were used in the study: the bare glass (glass sample A), the glass coated by hydrophobic silica sol (glass sample B), the glass coated by ethanol solution with SiO2 nano-particles (glass sample C) and the glass coated by silica sol with SiO2 nano-particles (glass sample D). The microscopic patterns of dust deposition, dust deposition density, spectral transmittance reduction and PV efficiency degradation of the four glass sample cases were studied in details. When the dust deposition time is 60 min and the tilt angle of glass sample is θ = 30°, the dust deposition density on the glass sample B, C or D is just 51.4%, 38.6% or 36.1% of the bare glass sample A, respectively. The super-hydrophobic coating with micro-nano structures (glass sample D) achieves the highest spectral transmittance and the lowest PV power efficiency reduction after dust deposition.