As operating temperature rises by 1 degree Celsius, traditional silicon-based solar cells will lose about 0.5% efficiency. In a typical photovoltaic plant, where modules operate nearly 25 degrees Celsius above the ambient temperature, energy losses can reach 12%. This necessitates effective cooling measures for solar farms.
Some modern cooling methods force wind or water to interact with solar panel surfaces, while others employ specific materials with less thermal sensitivity. However, these techniques require significant resources to operate. In contrast, a solar farm with optimally spaced panels facing the correct direction could cool itself through convection using the surrounding wind.
A team of scientists has improved models that calculate how much energy a given solar plant will produce based on factors such as material, environmental conditions, and panel temperature. They specifically focused on the geometry of solar farms, or how much ‘gappy-ness’ was present between the panels.
Focusing on their research work, Scientist Sarah Smith, of Portland State University, said, “Our hypothesis was that the most precise estimate of solar plant convection, and ultimately production efficiency, must consider the farm as a whole and all possible configuration changes.”
By design, it is rare that any two solar plants have the same setup. Each is uniquely designed to optimize solar irradiance and conform to its surrounding environment. For example, the tilt of solar panels changes with latitude and their height varies with vegetation. Spacing of rows often depends on how much land is available.
“This means that the heat-removing wind flow will also move differently throughout each solar plant based on its arrangement, ultimately changing how efficiently heat is removed from module surfaces,” explained Smith.
The researchers performed wind tunnel experiments and high-resolution simulations and collected real-world data to corroborate their model. They investigated photovoltaic heating and cooling with variations in module height, row spacing, angle, and wind. Raising the height of solar cells and increasing the spacing between panel rows increased power output by 2% to 3%.
“This correlation between geometry and efficiency is a huge step toward predicting convective cooling for solar farms based on their inherently unique arrangements,” said Smith. “It paves the way for more accurate energy generation and cost prediction models in industry.”
(The complete research work is available at https://doi.org/10.1063/5.0105649.)