Dust accumulates rapidly on solar panels in arid coastal desert regions where there is little rain or snow. Dew forms daily, causing dust to bond into a hard-to-remove mud layer that reduces panel efficiency by up to 26%. Cleaning is needed at least weekly to maintain acceptable performance levels, but manual cleaning uses much water and labor while automated systems also struggle with the hardened mud. An effective automatic cleaning method is needed that can remove built-up dust and mud without large water usage.

1. Solar panels are always covered by airborne dust Dust covered area cleaned area

2. Dew or light rain turns accumulated dust into hard-to-remove mud

3. Dew forms almost daily in coastal deserts. It causes dust to form a hard-to-remove mud layer. Number of dew nights in a coastal desert

4. Dust effect on glass coated mirrors is doubled since light passes through the dust twice - on the way in and out

5. Sources of dust Dust accumulation on solar mirrors occurs rapidly in arid regions where there is no rain and snow to keep the dust on the ground, slow its transport by winds or to clean the mirrors by natural means. Dust sources: - In the desert, the main source of dust are “loess” soil particles of local and not of local origin (from atlas mountains through Sahara desert). - In industrial or urban environment, the sources of dust are mostly of local origin (dust from roads, industrial soot etc.)

6. Cleaning Frequency: Weekly Efficiency Drop for Glass Mirrors in Arid Climates 14% Egypt 18% India 26% Kuwait - Negev (Sede Boqer) - data for 2 different weeks: 26% , 15.6% For focal point at a distance of 13m, above values should be multiplied by 1.17 Conclusion: Cleaning should be performed at least on a weekly basis to achieve acceptable level of performance!