| Work Detail |
A UK-Saudi research group has investigated the impact of uneven soiling on PV modules and has found that it can lead to enhanced performance losses due to different operational effects at intra-cell level. The academics conducted a series of experiments on a residential rooftop in Muscat, Oman, throughout 2021.
For the electrical characterization, the group used an indoor solar simulator that can replicate standard illumination conditions. It also applied thermocouples to the rear side of each solar cell to conduct temperature measurements. “Beyond the average loss in power, we are interested in the power variations over the tested spatial regions, and correlations between the power generation and the degree of soiling,” the researchers further explained.
The tests showed that nonuniform soiling on the mini modules can result in an average temperature increase of 2 C and a 13% average transmittance drop compared to the reference glass.
“The transmittance losses were found to be strongly correlated with power generation, with an average power deterioration of around 6–7% per 5% drop in transmittance,” the scientists stated. “Specifically, a power generation loss of 30%, 31%, 27% and 32% was measured relative to a clean sample across the four spatial regions/zones. Finally, a large solid formation was identified on the horizontal tilt sample, which gave rise to a localised hot spot.”
Looking forward, the researchers said more “regional” researchers are needed to define standardized metrics to assess soiling nonuniformity. “Our results highlight the importance of addressing PV soiling for optimal PV performance, and of accounting for spatial soiling nonuniformity,” they concluded. |
