Researchers Say Cooling Measures for Solar Farms Improve Efficiency by 2-3%
Raising the height of solar cells & increasing spacing improved power output
Researchers from Portland State University, the University of Utah, and the National Renewable Energy Laboratory (NREL) said they have identified a new method to improve efficiencies at solar projects through enhanced natural cooling which is achieved by utilizing the existing geometry of the farms.
The researchers found that a solar farm with optimally spaced panels facing the correct direction could cool itself through convection using the surrounding wind. It was identified that raising the height of solar cells and increasing the spacing between panel rows increased power output by 2% to 3%.
Contrary to common perception, too much sun or heat can reduce the efficiency of photovoltaics and they have been found to work more efficiently when operated at lower temperatures.
“This correlation between geometry and efficiency is a huge step toward predicting convective cooling for solar farms based on their inherently unique arrangements… and paves the way for more accurate energy generation and cost prediction models in the industry,” author Sarah Smith, of Portland State University said.
The team found that when the operating temperature rises by 1°C, silicon-based solar cells lose about 0.5% efficiency. For instance: In the case of a typical photovoltaic plant, energy loss would account for 12%, where modules operate at nearly 25°C above ambient temperature.
Modern cooling methods force wind or water to interact with solar panel surfaces, while others employ specific materials with less thermal sensitivity, but such techniques require significant resources to operate.
This necessitates effective and hassle-free cooling measures for solar farms.
Each farm needs a different cooling model
The team improved the models that calculate how much energy a given solar system would produce based on factors such as material, environmental conditions, and panel temperature.
This was done by specifically focusing on the geometry of solar farms, or how much space was present between the modules.
The working hypothesis was that the most precise estimate of solar system convection and production efficiency must consider the farm as a whole and all the possible configuration changes.
“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,” said Smith.
To corroborate their model, the researchers performed wind tunnel experiments and high-resolution simulations and collected real-world data.
This was followed by the investigation of photovoltaic heating and cooling with variations in module height, row spacing, angle, and wind.
Earlier, NREL had revealed that distancing rows of solar panels could help maintain the module temperature, which usually increases when solar modules are exposed to direct sun for a long time leading to a decrease in module efficiency.
In November 2022, a team of researchers at the University of Alcala in Spain claimed that a temperature reduction in solar modules by up to 20ºC can enhance the net system efficiency by about 14%.