Effect of dust and cleaning methods on mono and polycrystalline solar photovoltaic performance: An indoor experimental study

Abstract

Photovoltaic modules are affected by the weather and are sensitive to dust accumulation. The accumulation of dust causes obvious losses in the produced yield. To reduce these losses to a minimum, it is recommended to clean the photovoltaic units periodically by several cleaning methods. In this practical study, the accumulated dust was collected for a period of two months (March and April/2021) from five sites in the Wilayat of North Al Batinah – Oman. The dust components were examined, and the sources of these components were determined and their proportions in the dust of each city. The study adopted the examination of the effect of each component separately on the performance of monocrystalline and polycrystalline PV modules. The results showed that the contamination of 5 g/m2 on the monocrystalline PV module caused a decrease in the produced power by 12%, 6%, 6%, 7%, 3%, 4%, and 4%, for ash, calcium carbonate, limestone, cement, sulfur, sawdust, and brown soil, respectively. For polycrystalline module, at the same contamination (5 g/m2), the measured deteriorations were 5%, 4%, 4%, 1%, 2%, and 2% for ash, sand, limestone. sawdust, black silicon carbide and silica gel, respectively.The best manual cleaning methods were also studied to choose the optimal ones for each PV module and city. Polycrystalline are more affected than monocrystalline by the accumulated dust, with an average of not less than 10% at an accumulation rate of 50 g/m2 and 5.28% at an accumulation rate of 5 g/m2. The best way to clean PV modules to recover the largest percentage of yield losses is the sodium solution with rubber and cloth brushes. The study suggests, depending on the practical results, periodic cleaning periods from 10 days (for polycrystalline module in the cities of Liwa, Sohar and Barka) to 15 days (for monocrystalline module for all the cities studied).