A U.S. research team has found that increasing the spacing between rows of solar panels improves a PV system’s efficiency and economics by allowing airflow to cool down the modules. The method could improve a project’s LCOE by as much as 2.15% in certain climates. this report is in accordance with an article published in Renewable Energy World.
A new approach to utilizing heat transfer for solar module cooling in large-scale solar power plants has been proposed by researchers at the US Department of Energy’s National Renewable Energy Laboratory. Using factors such as row spacing, number of panels per row, and angle of tilt, they modeled the airflow around or through solar modules with dimensions that are appropriate for large commercial installations. In the standard models, the length often used is a ratio of module dimensions that ignores PV plant configuration.
“The convective heat transfer curve was generated through computational flow simulations and wind tunnel experiments that allowed for convective heat transfer to be described for a lacunarity length scale value that describes the spacing of the entire PV array through a single length unit,” the scientists said, claiming that using the lacunarity length scale leads to 1.5% more accurate power production.
A techno-economic analysis was conducted for 1 MW of south-facing PV systems located in Phoenix, Arizona. The analysis considered different row spacings and ground coverage ratios (GCR). The GCRs ranged from 0.73 to 0.08, with two-meter row spacing corresponding to GCRs of 0.73 and 11 meters corresponding to GCRs of 0.08.
“Increasing spacing could enable more varieties of crops and more types of agricultural equipment to be utilized in agrivoltaic systems,” said Jordan Macknick, who leads a different NREL research project focused on agrivoltaics. “That could potentially make these spaced-out solar systems more cost-effective and compatible with larger-scale agriculture.”
The group found that the optimal levelized cost of energy (LCOE) point was $0.29/kWh, with row spacing ranging from 4.83 to 7.34 meters. With two-meter spacing, the LCOE was $0.33/kWh, and with 11 meters it was $0.36/kWh.
The group discovered that the greatest LCOE improvements were registered in climates with low average annual ambient temperatures and moderate to high average annual wind speeds across the US. They presented the modeling in a study recently published in the IEEE Journal of Photovoltaics titled, “Technoeconomic Analysis of Changing PV Array Convective Cooling Through Changing Array Spacing”.
Other recent proposals for using convective solar module cooling include packing PV panels in close proximity, and taking wind direction and module inclination into account.
