Experimental and numerical analyses of water droplet condensation on photovoltaic surfaces under clean and dusty conditions

Several studies have investigated the condensation effect on dust agglomerate located on PV surfaces. The phenomena of dust condensation remain minimally addressed by researchers and not understanding well in the field of PV systems. Using rigorous experimentation, this research study explored the accumulation of dust on photovoltaic units. Furthermore, we thoroughly examined the effect of condensation on the glass surface of the unit. The formation of condensed droplets and their consequences were examined through meticulous experiments and mechanical analyses. The experiment was made possible by an ingeniously designed experimental platform, which enabled monitoring the influences of condensation on dust aggregation. The condensation process was carefully observed and analysed using microscopic techniques, while its direct impact on the dust accumulated on the PV module's surface was also examined. The experimental and numerical investigations of droplets condensation, condensing water droplets speed, condensation film thickness, and mud formation layer on the glass cover of PV module were highlighted. The droplets condensation on a glass plane (similar surface to covering glass for PV module) was recorded at different air conditions. The values of air velocity were chosen 0, 2.4, 4.1, 6.3 m/s, to provide a constant air temperature and humidity of the inflow air, the channel was supplied with heating control system. Furthermore, two dust seeding quantities 150 and 300 g were tested to provide a range for different cases for thickness of dust layers with different air velocities. According to the study, condensate time directly correlates with drop equivalent diameter, demonstrating that drop diameter increases proportionally to condensation time. It is indicated that the droplet formation and condensation period accelerated with increasing dust seeding quantity. It is noteworthy that the period of droplet formation and condensation accelerates with the increase in the amount of dust seeding. The results showed that by increasing the air speed from 2.4 m/s to 6.3 m/s, the weight of accumulated dust was decreased from 0.166 g to 0.151 g. Also, the average mud layer thickness was reduced from 27.6 μm to 25.1 μm.