Scientists have developed a precursor formulation for various PV simulation tools that can help calculate the expected performance of solar farms on hilly slopes. Validation tests against an experimental setup showed a mistake of less than 3%.
Researchers from the East West University of Bangladesh have developed a new method for analyzing bifacial PV systems in sloping sites. The new technology is a precursor that is then inserted in existing PV simulation models that do not explain hilly solar farms.
“The proposed method includes the recalculation of the solar path and the irradiation (direct and diffuse) to that of ‘seen from a sloping surface’ and these values in a conventional PV model. The updated inputs ensure that the overall outputs are the results for a PV -Array, the studies. “We are therefore able to design and analyze PV farms for every slope and orientation without reformulating another part of the existing PV models.”
The technology consists of three parts: the modeling of the solar path on a certain hill; the correction of the sunlight values; And the integration into existing models. In the first step, the global coordinate is rotated together with the orientation and corner of the slope. This process yields a modified solar path from the point of view of the tilted surface.
In the second step, the diffuse horizontal radiation (DHI) is reduced based on the viewing factor of the slope in the sky, while the direct normal irradiation (DNI) remains as it is. The new DHI value is responsible for the limited exposure to the air of the hilly surface. In the last step, the corrected incidence and sun corners are inserted into available PV models, which they treat as flat soil.
The team has validated their model in a few ways. In most cases, self-validation found an error of a maximum of 2% and benchmarking against the PVsyst software, which can take into account sloping trees, has yielded comparable results. Finally, the team also built a small -scale experimental setup, including a monofacial array of a panel placed on a hill on the east with a slope of 20 °. The panels were placed flat against the slope, at a height of 51.5 cm and a width of 28.5 cm.
Image: East West University, Energy Conversion and Management: X, CC by 4.0
“This experiment was carried out on the roof of East West University, Dhaka (23.8Z, 90.4Ze) for 10 days of February-March 2022. The output was measured every 2 minutes from 6.30 am to 6:00 pm, then integrated over the day to get the daily energy output,” the team explained “.Lobal HOrizontal I.Radiance (GHI) as an input for the combined model to simulate the output of the same configuration and location. The comparison between the energy output of our combined model and it showed a daily error of less than 3%from the experiment. “
Finally, the team demonstrated their model, using their precursor formulation with the PV-maps simulation software. They tested an angle of 20 °, on a hill with North, South, East or West. The panel, monofacial or bifacial, was mounted parallel to the slope. In the bifacial simulation they adopted a bifaciality of 1 (unit) and an albedo of 0.2. All panels had an efficiency of 16.8%, with panel height and luminaire height of one meter.
The analysis showed that the Bifacial PV system yields a higher output, as expected, with the annual energy of the bifacial PV systems on different hills ranging between 211,33 and 290.45 kWh/m2/year and the monofacial PV system that is taken from 187.18 to 259,72 KWH/year….
“In general, the developed model simplifies the implementation of numeric models for bifacial panelarrays on sloping terrain. The models for mono/bifacial farms, mono/bifacial (single junction and tandem) tracking farms, and agrivoltaics systems can now be refunded for cortemes systems -Surfaces for predictions and analysis, “the team concludes.
The new approach was presented in “Modeling of every Bifacial solar panel Array configuration in the helly site: generalization using a precursor formulation“Published in Energy conversion and management: X.
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