Fig. 1 shows a schematic diagram of the system. If the system is
operated intermittently, the sand that has adhered to the cover
glass of the solar panels is repelled. On the other hand, if the system
is operated continuously, the sand that approaches the cover glass
is also repelled, and thus, the system can protect solar panels
against the adhesion of sand.
Six types of sand, collected from desert areas around the world,
were used for evaluation. Photographs of the sand particles are
shown in Fig. 2, and these specifications are summarized in Table 1.
Sand A was commonly used in the experiments unless otherwise
specified.