Measurement of dust sweeping force for cleaning solar panels

A new methodology has been developed to evaluate cleaning efficiency of dust particles on solar panels. Those particles have an average diameter of 2.3 µm and were collected in Doha, Qatar. A brush-disk configuration was constructed to measure the sweeping force as a polymeric tip sliding through a dusted glass substrate. The sweeping force was measured under various applied loads on samples treated in environment of various humidity. Experimental results showed that the cleaning efficiency of dry dust particles was independent of the applied load, reaching higher than 90%. However, the adsorption of water molecules showed pronounced effects on the cleaning efficiency. In order to increase the efficiency in humid environment, the applied load thus needed to be increased. The higher the applied load, the higher the sweeping force, the higher the cleaning efficiency, indicating more power is needed to clean the surface. This research presented an alternative approach to evaluate the cleaning efficiency of dust particles.