Particle-size dependent parameter studies for laboratory soiling tests: influence of temperature, relative humidity and tilt angle

The energy yield loss of PV modules due to soiling is an important performance factor and can become catastrophic in dusty environments. As the environmental conditions vary from region to region, soiling also varies, and its evaluation is a challenging element in the field of PV research. For that reason, an advanced laboratory soiling setup was developed for the evaluation of the anti-soiling performance of glass coatings under different soiling and controlled environmental conditions. The sequential methodology allows for testing the impact of environmental parameters individually. Within this study, we present an in-depth analysis of the influence of surface and ambient temperatures, relative humidity as well as tilt angle on the dust deposition. It is shown that - depending on particle size - the effects of natural convection, thermophoresis, capillary condensation and rebound can have crucial impact on soiling and the outcome of laboratory soiling tests.