The Water-Cooling Effect of Floating PV Systems

The Water-Cooling Effect of Floating PV Systems

What is the water-cooling effect of floating PV systems? How to estimate the temperature of photovoltaic modules?

Scientists from the United States and Brazil developed four different methods to estimate the temperature of photovoltaic modules in the floating PV solutions. They used temperature measurements from floating solar farms in Brazil to verify these models.

Researchers at the University of Louisiana at Lafayette and scientists at Punta Groza State University in Brazil developed four models to estimate the temperature of floating photovoltaic modules of floating PV systems in various climatic conditions, configurations and locations.

They created a three-layer thermal model, a simplified thermal model, an empirical model, and a computational fluid dynamics (CFD) model. They applied the model to a single 330WP JA Solar module in a floating solar system in Lake Passona, Brazil, between May 2020 and September 2022. The system has an installed capacity of 130kW and covers an area of 1,200 square meters.

A more complex thermal model studies the dynamic behavior of the solar cell temperature in three layers of the solar module: the front surface, the cell surface, and the back. Simplified thermal components treat the temperature of the component as a whole. The empirical model calculates the temperature on the back of the component using the site data through the least square linear regression analysis method. The CFD modeling also uses the finite element method (FEM) to determine the temperature on the back of the component.

The scientists say the results show "a good correlation between the four proposed models and the actual data collected from the field, with [root-mean-square deviation (RMSD)] in the range of 0.5 degrees to 4.8 degrees." The complex thermal model showed the best fit with RMSD of 2.04 degrees, followed by the empirical model of 2.27 degrees. The simplified thermal model is 2.89 degrees, and finally, the CFD model is 3.26 degrees. However, the simplified thermal model shows that a linear fit line following the actual temperature of the component gives the best results.

The scientists also compared the efficiency of solar modules of solar PV systems to a ground-mounted PV system modeled by Sandia National Laboratories. The results show up to a 3 percent increase in efficiency compared to the ground-mounted Sandia National Laboratories model.

"The water-cooling effect plays an integral role in the efficiency of floating PV modules. As the temperature of the battery drops due to its proximity to water, the efficiency increases, "the expert explains.