Does, for example, a N-S SAT tracker azimuth follow the East - West direction or the torque tube? I would say the azimuth and elevation define the normal vector of any PV panel on it, but I'm not at all sure.

A distinction needs to be drawn between the angles that define the orientation of tracker and the angles that define the orientation of the modules on the tracker. A single-axis tracker with N-S axis has constant axis_azimuth=180 (or zero, but 180 is better). The modules on the tracker will have surface_azimuth=90 in the morning and surface_azimuth=270.

I will take a closer look at this PR in the coming days. Thanks for your patience @echedey-ls!

Lot of thanks for clearing this up. Now I feel like it's obvious.

Don't worry about the review. I know it's premature to open a PR based on another one (I've got yet another one in the drawer that needs this implementation to work, sorry 😬 )

I'm late jumping in here, but one thought I have: does this need to be limited to trackers? Or can the function name and variable names be updated to more generally cover fixed or tracking rows?

It should work for fixed tilt just fine, so not limited to trackers

Thanks, @mikofski. It seems like it would be helpful to change:

• the function name from tracker_shaded_fraction to shaded_fraction,
• the variables tracker_tilt and tracker_azimuth to surface_tilt and surface_azimuth, and
• references in the docs to “trackers” to “rows”

or something like that.

Maybe I misspoke. Sorry, I meant to say that it could be repurposed for fixed tilt with some care, but, I’m not sure if we should make it all purpose for both fixed tilt & SAT. For one, tracker azimuth and surface azimuth mean different things, so we can’t just swap them.

I think it would work if we treat fixed tilt as a tracker aligned east to west and set the tracker azimuth to either 90° or 270° measured clockwise from north, or 90° from the surface azimuth. Like a similar issue you raised recently, if azimuth were 90° then tilts would be negative if north and positive if south.

Currently this algorithm doesn’t seem to account for tracker axis tilt, but as I mentioned in the original PR #1725 I think it could be managed when calculating projected solar zenith? A tracker axis tilt would correspond to an east-west slope for a fixed tilt.

Anyway I apologize for being too glib, I should have been more careful in my replies, again sorry.

I agree with @williamhobbs. surface_tilt and surface_azimuth terms seem to apply to all contexts independently of the used tracker, so they are less prone to be misunderstood by a user.

Well spotted, I always miss something...

FYI I believe @AdamRJensen plans to review as well.

All feedback is welcome, even better if it comes from one of the authors 😉

Everything's ready IMO 😄 . Feel free to review and propose changes 📝

I just fixed a syntax issue and linter issue, and then fixed a new syntax issue I introduced...

Thanks for this great contribution @echedey-ls!

Excited to see this merged! Thanks to everyone that helped move this forward!!