In brief
The fixed calculation parameters of the simulation, including time step, sun model, solar diameter and calculation grid, cannot be changed; the report documents them in the chapter "Simulation Parameters".
| Parameter | Value |
|---|---|
| Temporal resolution | 1 minute, reference year without a leap day (1 January to 31 December) |
| Solar position | NREL SPA (pvlib), apparent elevation including refraction, calculated at the mean of all PV corner points of the project (one solar position for all areas) |
| Solar elevations calculated | above 0° |
| Time reference | project time zone as standard time, without daylight saving time |
| Direct irradiance (DNI) | clear-sky model according to Ineichen and Perez, climatological Linke turbidity per month, site altitude = mean terrain height of the PV corner points (one altitude per simulation) |
| Luminous efficacy (K) | dependent on solar elevation according to Littlefair (1988), 51.8 to 96.6 lm/W |
| Apparent solar diameter | 0.53° |
| Module curves | reflection profile, major and minor axis per zone (up to three zones), reflection offset δ; 10° supporting points, interpolated linearly |
| Reference illuminance of the profiles | 100,000 lx on the module surface, independent of the angle of incidence |
| Lobe boundary | ellipse with semi-axes (lobe axis + solar diameter) / 2 |
| Point grid (calculation points) | per PV area and axis (azimuth, elevation) about 40 steps across the extent at which the area appears from the observation point; step width at most 0.125°. Finer step widths are snapped to the nearest divisor 0.125°/n, with at least 30 steps per axis; the cap of 20,000 points per area takes precedence. Points at the edge of the area count with the area share of their grid cell. In the report "Spatial resolution" |
| Cell grid (assessment) | 0.5° × 0.5° (azimuth × elevation), fixed |
| Capture margin of the hit check | half the cell diagonal, 0.354°; for narrow lobes (smallest semi-axis < 1.5°, largest < 6°) half the diagonal of the point grid |
| Display grid | 0.5°, 0.25° or 0.125° per PV area; display only |
| Back side / grazing view | no reflection when seen from behind; for ground-mounted and racked areas already at more than 89° between viewing direction and module normal; for trackers per time step and calculation point |
| Cell rules | blocked if more than half of the points are; outside the field of view if all points are outside; shaded according to the ray from the cell centroid and, with terrain occlusion, the nearest sampling point |
| Obstacle silhouette | 0.05° azimuth per step, per observation point |
| Terrain occlusion | near horizon per observation point, 2 m grid, 0.5° azimuth, steps of 0.05°, range up to 10 km; shading of the PV areas at sampling points in a 25 m grid (coarser for large installations, at most about 600) at the height of the module top edge, range 2 km, sampling with the grid spacing, further out 1 % of the distance; if switched on |
| Horizon lines (far-field shading) | PVGIS, 48 directions, per PV area at the centre of the corner points; if activated |
| Trackers | tracking angle per time step (pvlib), backtracking with GCR, rest angle during backtracking; all tracking parameters required, no substitute values |
| Elevation data | source chain of the project (Ch. 6); the report lists the sources used |
The app sends the values for temporal resolution, solar diameter and the upper limit of the point grid as fixed values with every simulation start; they cannot be changed. The report documents the parameters used in the chapter "Simulation Parameters" (Ch. 14).