📐 PV Mounting Tilt & Row Spacing Calculator
Find the optimal tilt angle for a location and the row spacing needed to avoid winter-solstice shading, from the site latitude and module dimensions.
📐 Location & Module
📊 Tilt & Spacing
For solar designers laying out ground-mount and flat-roof arrays.
How it is calculated
· Optimal tilt: β = 0.76 × latitude + 3.1 (auto).
· Winter sun altitude: α = 90 − latitude − 23.45.
· Shadow length = h ÷ tan(α); row spacing = module-length × cos(β) + shadow.
Referenced standards
| Standard | Scope |
|---|---|
| — | Geometric design guide (industry practice) — no single governing standard; confirm structure for wind/snow loading with a structural engineer. |
Worked example — latitude 30° → 25.9° tilt
1. Latitude 30°, module 2278 × 1134 mm.
2. Optimal tilt = 0.76 × 30 + 3.1 = 25.9°.
3. Winter sun altitude = 90 − 30 − 23.45 = 36.6°; tilt height = 2.278 × sin 25.9° = 1.0 m.
4. Shadow = 1.0 ÷ tan 36.6° = 1.34 m → row spacing ≈ 3.4 m.
FAQ
What tilt angle maximizes annual solar yield?
For fixed-tilt, annual yield is near-maximal when tilt equals latitude (e.g. 30 deg at 30 deg N), with latitude minus 10-15 deg favouring summer and plus 10-15 deg favouring winter. The calculator optimizes tilt for your latitude and lets you weight summer vs winter production.
How do I calculate PV row spacing to avoid shading?
Row spacing must keep the winter-solstice shadow of one row off the next, computed from the sun's lowest noon elevation. At 30 deg latitude with 20 deg tilt and 1 m module height, spacing is roughly 2-2.5 m between rows. The calculator computes spacing so no shading occurs during the design hours on the winter solstice.
How does row spacing affect land use and yield?
Wider spacing (lower ground coverage ratio) reduces shading losses but increases land area. Ground coverage ratio (GCR) typically ranges 0.3-0.5 for fixed-tilt plants; a GCR of 0.4 uses 2.5 m2 of land per m2 of module. Tight spacing raises rear shading and cuts yield 2-5%; the calculator shows the spacing-yield trade-off.
What is the optimal azimuth for a PV array?
In the northern hemisphere, due south (azimuth 180 deg) maximizes annual yield. East- or west-facing arrays lose 10-15% annual energy but shift production toward morning or evening, which can be valuable for self-consumption or time-of-use tariffs. The calculator accepts azimuth and adjusts the yield estimate.
How does mounting type affect yield — fixed vs tracker?
Single-axis trackers add 15-25% annual yield over fixed-tilt (more at low latitudes), and dual-axis adds 25-35%, but trackers cost 15-30% more and add maintenance. The yield gain must beat the cost premium. The calculator's fixed-tilt model is the baseline; tracker economics are compared in the payback step.
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