Indoor experiments of dust deposition reduction on solar cell covering glass by transparent super-hydrophobic coating with different tilt angles

Dust deposition on solar photovoltaic (PV) panels would greatly reduce the PV output efficiency, especially in dusty regions. This paper investigated dust deposition reduction on solar cell covering glass by transparent super-hydrophobic coating under different PV tilted angles. The macroscopic and microscopic dust deposition patterns, dust deposition density, spectral transmittance of covering glass and PV efficiency reduction caused by dust deposition were studied and analyzed. The results showed that dust deposition on the glass surface can be greatly reduced by super-hydrophobic coating due to the low adhesion energy. The super-hydrophobic coating has a better performance on dust deposition reduction compared with hydrophobic coating. The deposition density on the glass with super-hydrophobic coating is just 44.4%, 28.6% or 11.2% of the bare surface for tilt angle theta = 30 degrees, theta = 45 degrees or 60 degrees, respectively. The spectral transmittance of coated glass and the PV efficiency are obviously higher compared with bare glass case after dust deposition. Moreover, the self-cleaning coating has better performance for large tilt angle and poly-crystalline silicon PV cell. The performance of super-hydrophobic coating on dust deposition reduction is similar between the test dust and the real dust obtained from Guangzhou, China.