Analysis of natural sand for soiling tests and qualification of solar glass with a soiling sensor

Solar glass is used as glazing for solar devices like photovoltaic modules and solar-thermal collectors. In desert regions dust accumulation can lead to extreme efficiency losses due to soiling, with previous results of up to -80% in 6 month. For a reproducible qualification of different glass types, surface structures and functional coatings an in-house developed soiling test device soils samples homogenously with any kind of natural or standard dust. To determine the effect and interaction between the surface and the different types of deserts sand from all over the world, the dust properties are investigated. Grain format, particle size distribution, sand colour, and chemical composition has been analysed. Also dry dusting tests have been performed. The loss of transmittance due to the dust layer has been measured with the in-house built transportable soiling sensor directly at the location of soiling. Prospectively further testing will be done to understand the mechanism of soiling, the interaction with different surfaces and the effects of anti-soiling coating in solar applications. Results are also most likely the be easy to transfer to other application, such as buildings.