Reduction in solar PV soiling loss using hydrophobic coating with and without dew suppression

Abstract

The deposition of particulate matter (PM) on PV surfaces reduces energy generation, which results in huge losses to the PV industry. Hydrophobic coatings are known to reduce PM deposition on PV surfaces. Covering panels during the night is expected to reduce the PM deposition as well as suppress the dew formation on the surface. The objective of the present study is to compare the soiling on the hydrophobic coating with and without dew suppression. Uncoated and hydrophobic coated slides were kept for PM deposition in a 70-day field study. The dew formation was suppressed on some of the uncoated and coated slides by covering them from sunset to sunrise. The results show that the % reduction in soiling of coated slides under dew suppression is higher (50 ± 13%) compared to the coated slides without dew suppression (31 ± 15%) (statistically different; two-tailed p-value < 0.05). In addition, the particle size analysis using optical microscopy shows that the hydrophobic coating (under dew suppression) reduces the particles deposition by 60.0 ± 8.1% (mainly 10 to 30 μm range) compared to the uncoated slides (under dew suppression) over the entire sampling period. However, the dust potency (soiling loss per unit deposited mass loading) for uncoated and coated samples is found to be statistically similar (5 to 6 % g−1 m2; two-tailed p-values > 0.05). Overall, the present study advances the understanding of the impact of dew on hydrophobic coating, thereby adding to the existing knowledge of soiling mitigation approaches for solar PV industries.