Developed by Spanish scientists, the proposed model aims to reduce yield losses caused by the fact that north-south aligned single-axis trackers are often deployed on uneven east-west slopes.
Researchers from the Universidad Politécnica de Madrid (UPM) has developed a two-dimensional (2D) modeling tool for deploying large-scale bifacial PV installations using single-axis trackers over terrain with arbitrary orientation and slope.
The proposed model aims to reduce yield losses caused by the fact that north-south aligned single-axis trackers are often deployed on uneven east-west slopes.
“This article first outlines some relevant assumptions that standard PV software relies on to simplify energy yield simulation and points out the horizontal constraint, which does not necessarily require the ground to be horizontal, but only that the angle of inclination about the axis is zero ”said the author. according to research group. “Next, the mathematical basis for adjustments to overcome the horizontal constraint while maintaining these assumptions is described.”
The scientists used the Sisifo software, an open PV simulation tool developed by the UPM itself, and said it can overcome the horizontal limitation of conventional modeling solutions while still relying on 2D modeling and a representative array with one tracker. Simple equations were also developed to monitor the motion control of the trackers.
The proposed approach assumes that the axle length is infinite and that the axle height above the ground is constant over the entire length. “This leads to a reliance on 2D modeling, which reduces the description of the geometry to a projection onto a plane perpendicular to the axes of the tracker, i.e. the cross-axis plane,” the academics explained. “On the other hand, it is assumed that the number of axes is infinite and that the axes are periodically arranged so that they all lie in the same plane, parallel to the ground and equidistant from each other.”
Thanks to the software, the researchers analyzed a single-axis bifacial PV installation over a terrain that slopes only in the east-west direction, with each specific case defined by the ground slopes and the azimuth of the axis. They also simulated a benchmark PV plant deployed on a horizontal site with a south-facing axis.
The analysis revealed that PV installations on versatile sites should be addressed by considering that the sites are composed of a series of smoothed areas, each with a defined azimuth and slope, with each area hosting a series of sub-axises with a defined axis. azimuth. The modeling was described in the study “Single-axis tracking and bifacial reinforcement on sloping terrain”, published in Progress in photovoltaics.
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