How condensation causes dusty solar panels

Solar panels are an increasingly promising renewable energy alternative to fossil fuels and a useful tool for reducing greenhouse gas emissions. However, dust agglomeration on the surface of photovoltaic panels causes damage and impedes their ability to efficiently turn sunlight into electricity.

Because condensation is a driving force in dust aggregation, Hu et al. investigated the dust agglomeration process during condensation. Their results will inform the design of future photovoltaic panels to reduce dust agglomeration.

Condensation and dust are unavoidable operation conditions, but too much dust deposition can prevent solar radiation from entering solar cells and can cause the panels to overheat, further impeding the photoelectric efficiency.

The team examined the effect of a condensation simulator on a hydrophilic photovoltaic panel using a microscope and high-speed camera. They observed how the droplets evolved from above and on the side.

The surface tension of water droplets proved to be the main dynamic factor behind dust agglomeration and caused a surprising, tiled pattern on the panel surface.

“Since the semi-submerged particles are subject to surface tension in different directions during the fusion process of droplets, a combined force and surface tension moment are created to make the particles move and roll, resulting in the agglomeration of particles,” said author Jianlan Li.

To design more dust-resistant solar panels, the authors recommend mechanisms like superhydrophobic coatings that reduce the contact area between the dust particles and the photovoltaic surface.

Source: “Experimental and mechanical analyses of dust agglomeration on photovoltaic surfaces due to condensation,” by Guoqiang Hu, Pengluan Huang, Xiaodong Zhao, Luyi Lu, Honggang Ding, and Jianlan Li, Physics of Fluids (2023). The article can be accessed at https://doi.org/10.1063/5.0136421 .