Multi-Axis Smart Solar-Tracking PV Systems

Reference: Trina Solar Vertex N TSM-NEG21C.20, 730 W bin. The official TSM_EN_2025_C datasheet specifies nominal bifaciality 80% (±5%), NOCT 43 °C (±2 °C), power temperature coefficient −0.29%/°C and dimensions 2.384 × 1.303 m. Tracking and flat use those same module parameters. Selected front-rated installed capacity: 1 kW. The 730 W, 900 W and 1 kW choices compare system capacities; they are not three single-module ratings in this series. With the same mounting geometry and loss assumptions, watts and every energy term scale by capacity in kW; temperature and percentage gain stay unchanged. An actual larger array changes layout and shading and requires its own model. Both sides use Ineichen–Perez clear sky and a shared Hay–Davies split: circumsolar diffuse joins sunlight from the sun direction; the remainder is isotropic skylight. Both faces and the roof use that same split and shadow treatment. A near-horizon projection limit preserves horizontal irradiance. Ambient temperature is 20 °C and the generic system-loss factor is 0.86. Direct and circumsolar light use ASHRAE incidence-angle correction; remaining skylight and reflection use an assumed 0.95 transmission factor. The flat panel lies directly on the roof: its back rests against the roof and receives no light, so only the front counts; a horizontal front sees no roof either, so the flat result does not depend on roof color. The tracker is raised above the roof. Analytical polygon view factors are integrated over a 48 × 96 roof grid with 4 × 4 shadow probes per cell. The module obstructs roof skylight; visible rear skylight is added separately. Current assumptions: 60% roof reflectance; a 4 × 2 m horizontal roof with its long axis north–south; 0.15 m lowest-edge clearance for the tracker, with its center rising with tilt; no support shading; 2% rear mismatch. The 15 cm lowest-edge clearance is a scenario assumption, not a measured product dimension; geometry and reflectance are assumed. Tracker effective irradiance = front effective irradiance + rear effective irradiance × 0.80 × 0.98. Both faces affect temperature; power is integrated every 5 minutes. Net rear contribution = combined output minus a front-only calculation. The front-only calculation uses the same front irradiance without rear-induced heating. The net increment therefore deducts the extra heating loss on the front; it is not roof-reflected electricity alone. Today at 1 kW: tracking 6.68 + 0.20 = 6.88 kWh; flat 2.82 kWh, front only; figures rounded independently. Gain = total tracking energy / flat energy − 1, so a lighter roof raises the gain along with the tracker’s rear output. The chart keeps a common 1 kW comparison axis so capacity changes remain visible. Ground beyond the roof, multiple reflections, cloud, nearby obstructions and soiling are excluded. Ideal full-travel tracking is not the existing 720 W product’s 0–45° mechanical range; this calculator reference does not replace reviewed product-page specifications. Local standard time, no daylight saving. Representative clear-sky days are not annual yield. Model home-roof-bifacial-4.0.0 is not calibrated to vehicle measurements or equivalent to the device gain reported against an optimal fixed-tilt reference with measured weather. Trina Solar datasheet ↗