# Backtracking: system with many sub-fields

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I'm designing a system with backtracking (horizontal axis tracking and no tilt) however the shape of the land is such that I have to use many sub-fields in order to make efficient use of the available land area. Throughout the system the pitch between all trackers is uniform and so is the collector width.

For such a uniform system in which backtracking is defined for multiple sub fields how do the backtracking calculations work? Are the shading effects between sub fields taken into consideration or is each sub field considered independently and then the performance of the system is some combination of the performance of these individual sub fields?

Many thanks!

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The backtracking strategy is only possible with flat systems, where the trackers are at a same altitude.

Backtracking between trackers at different altitudes is not possible in PVsyst, and doesn't make sense in the reality (except if you have a very special system with individual backtracking algorithm for each pair of tracker).

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So the altitude for all the sub-fields is the same. The pitch is also constant both within sub-fields and between sub-fields. The collector width is also constant throughout the system. The shape of the land is not a rectangle so many rectangular shaped sub-fields of different sizes have been used to utilise all the land.

My question was how does the PVsyst backtracking algorithm handle the mutual shading between adjacent sub-fields in this case? Is this system one that the back-tracking algorithm could accurately model?

Many thanks!

Thomas

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For the calculation of the backtracking angle, PVsyst has to use the pitch and wdth of 2 adjacent trackers.

This is only possible with trackers of a same tracker object (array of trackers). When you have several arrays of trackers, PVsyst will choose the more "narrow" as reference.

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• 1 month later...
For the calculation of the backtracking angle, PVsyst has to use the pitch and wdth of 2 adjacent trackers.

This is only possible with trackers of a same tracker object (array of trackers). When you have several arrays of trackers, PVsyst will choose the more "narrow" as reference.

I read this as stating that PVsyst requires two trackers to be at the same orientation (no misalign or azimuth changes). If I have two trackers of the same orientation, and another two that are misaligned which are adjacent to the first two, is this acceptable and able to be properly captured? See image for reference.

Thank you,