Tracker configuration

The Tracker Configuration group appears in Single Axis Tracker mode only. Choosing a tracker mode at launch replaces two fixed-tilt groups — the table configuration and the spacing and tilt group — with this single group, because a tracker has no fixed tilt to derive and no row pitch to calculate. You set the east–west pitch directly, and everything else follows from the tracker unit itself. For the fixed-tilt equivalent see Table configuration.

The geometry the fields describe

The tracker modelled here is a horizontal single-axis tracker. Four facts about its geometry make every field in the group read straightforwardly:

• The rotation axis runs north to south, along a torque tube. The tube is horizontal; the tracker does not tilt toward the equator the way a fixed table does.
• The panels sweep east to west as the axis rotates through the day, facing the morning sun in the east and the evening sun in the west.
• A tracker unit is a run of modules along that axis — modules threaded north to south down one torque tube, driven together.
• Units sit end to end north to south, forming columns spaced east to west. A gap is left between consecutive units in a column for access and for the drive gear; the spacing between columns is the pitch.

Placement follows the same shape: the application works east to west across tracker columns, and north to south along the units within each column.

Two terms recur below. Aperture is the east–west width of the modules on one tracker, measured flat — the collector width that sweeps. GCR is the ground coverage ratio, the aperture divided by the east–west pitch.

The fields

P and L configuration

Module orientation decides which module edge runs east–west across the torque tube, and so how wide the aperture is for a given module count.

P config is the default: one module deep across the tube, with its long edge sweeping east to west. L config puts the module's long edge along the tube instead, which shortens the aperture and lengthens the row for the same module count.

Because the aperture is the numerator of the GCR, changing configuration without changing the pitch changes the ground coverage ratio — and therefore the shading, the capacity per hectare and the number of columns that fit. Check the preview line after changing it.

Gaps within and between units

Three clearances are set here, two inside the unit and one between units.

Gap between modules E–W is the space between modules sitting side by side across the tube, and applies only when Modules across tracker (E–W) is more than one. At the default of one module across, it has nothing to act on.

Gap between modules N–S is the space between consecutive modules along the tube. It is applied between every pair of neighbouring modules down the whole run, so on a long unit it accumulates.

N–S service gap between units is the clear ground left between one unit and the next in the same column — the access and drive-gear allowance. It ships at 2.0 m and is the figure the cleaning-robot sizing takes as the span of a standard bridge between units, so a realistic value matters beyond the geometry.

The four relations

Four figures come out of the group, each from one line of arithmetic:

modules along tube = strings per tracker × modules per string

aperture (E-W)  = modules across × module E-W dimension
                  + (modules across − 1) × E-W module gap

length (N-S)    = modules along tube × module N-S dimension
                  + (modules along tube − 1) × N-S module gap

GCR             = aperture ÷ east-west pitch

modules/tracker = modules across × strings per tracker
                  × modules per string

The gap terms matter. Gaps sit between modules, so a run of n modules carries n − 1 gaps — and with 56 modules along the tube, that is 55 of them.

A worked example on the defaults

Take the shipped defaults throughout: a 2.38 m by 1.13 m module, both module gaps at 0.020 m, P config, 1 module across, 2 strings per tracker, 28 modules per string, and a 5.5 m east–west pitch.

P config puts the long side east–west, so the module's east–west dimension is 2.38 m and its north–south dimension is 1.13 m.

modules along tube = 2 × 28                    = 56

aperture        = 1 × 2.38 + 0 × 0.020         = 2.38 m

length (N-S)    = 56 × 1.13 + 55 × 0.020
                = 63.28 + 1.10                 = 64.38 m

GCR             = 2.38 ÷ 5.5                   ≈ 0.43

modules/tracker = 1 × 2 × 28                   = 56

A default tracker unit is therefore one module wide with a 2.38 m aperture, 64.38 m long north to south, carrying 56 modules in two strings, at a ground coverage ratio of 0.43. With one module across there is no east–west gap to add, which is why the aperture is a clean multiple; the north–south length is not. Add the service gap of 2.0 m to the 64.38 m length to get the north–south spacing each unit consumes in its column.

The live preview

A preview line sits directly under the group and reports those same four figures — Aperture (E-W), Length (N-S), GCR and Modules/tracker — recalculated as you type. It updates before you generate anything, so it is the fastest way to converge on a unit you are happy with.

Use it for three checks in particular:

• The GCR is in the range you intend. Pitch is the only lever on it, and raising the pitch lowers the GCR.
• The north–south length is credible against the site. A unit longer than the usable ground is available in that direction will not place at all, and the layout will come back sparse or empty.
• Modules per tracker matches the electrical design. This is the count the string monitoring or inverter limits are applied to.

Setting the unit up in order

The fields interact, so work down them in this order and let the preview line confirm each step before moving on.

Rotation limit and tracker height

Two fields describe the tracker's mechanics rather than its footprint, and it is worth being plain about how far they reach.

Max rotation angle (±) is the rotation limit either side of horizontal, 55.0° as shipped. It is a reference and shading-analysis figure. It does not move a tracker unit on the ground and does not change the pitch: on a tracker plant the summary reports this angle in place of the fixed-tilt tilt column, so the drawing and the schedule carry the mechanical limit you specified.

Tracker height from ground is the height of the torque tube above ground, 1.5 m as shipped, and is likewise a reference and shading-analysis figure rather than a placement input. It does not alter what is placed where.

No tilt, no row pitch

A fixed-tilt design derives its tilt from the site latitude and its row pitch from the no-shading condition at winter solstice, and lets you override either. A tracker design has neither control, by construction:

• There is no tilt to derive. The axis is horizontal and the panels rotate; the angle that matters is the rotation limit, which you state directly.
• There is no pitch to derive from a shading condition. You set Tracker E-W pitch yourself, and the GCR is reported as the consequence rather than as an input.

That makes pitch the one number to think hardest about on a tracker plant. A tighter pitch raises the GCR and fits more capacity into the site; it also raises row-to-row shading in the early morning and late afternoon, which is exactly when a tracker earns its premium over a fixed plant. See Shading losses for how that loss is estimated.

Packing options

Both packing options work as they do in Fixed Tilt mode, on tracker units instead of tables:

• Maximize placement, off as shipped, positions each tracker column independently against the exact edge of the usable area rather than starting every column from a shared origin. It fits extra units against diagonal and curved boundaries, at the cost of columns that no longer line up and a longer run on a large site.
• Add half trackers in leftover space, off as shipped, allows a shortened unit where a full one will not fit. Half units are reported in their own summary column and count as half a unit wherever units are weighted.

Both are covered in detail on Maximize placement and half tables.

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