Understanding row orientation for 1-axis solar

Hello, I am using the detailed PV model in SAM and am trying to understand the relationship between the azimuth in the "System Design" group and the rows in the "shading and layout" group.

I'm trying to model a 1-axis solar farm with rows oriented north-south, kind of like this random solar farm I found on google maps: www.google.com/maps/place/37%C2%B000'11.5%22N+120%C2%B057'20.5%22W/@37.003022,-120.9555268,156m

As I understand it, the correct azimuth to model this 1-axis orientation would be 180. However, when thinking about the side and bottom of rows, I'm confused about whether I should be thinking about rows looking at the array from the perspective parallel to the rotational axis (from the south) or perpendicular to the rotational axis (from the east or west).

For example, looking at the example in the Google map, I would say that if I were standing on the east side of the array and looking west, the panels would be in portrait orientation, with 1 module along the side of the row, and lets say 100 modules along the bottom of the row.

However, if I were looking at the array from the south, I might say that the panels are in landscape orientation, with 100 modules along the side of the row, and 1 module along the bottom of the row.

So for a 1-axis system, does a row run parallel to the azimuth, or perpendicular to the azimuth, and which convention should I use for specifying the system layout?

Hi Greg,

I would model an array like the one you found on Google Maps as follows, assuming each row is 1 x 100 modules:

Azimuth = 180 (assuming a north-south rotation axis)
Modules along bottom = 100
Modules along side = 1

Marion (2013) "Rotation Angle for the Optimum Tracking of One-Axis Trackers. National Renewable Energy Laboratory" might shed more light on that. You can download it here: sam.nrel.gov/photovoltaic/pv-publications.html

Best regards,
Paul.

Thank you for confirming this Paul