pvperfsolar performance modeling

Reference

API field

Rear-side geometry

The rear model's slope length, clearance, transmission and structure shade

What it is

Selects where the rear model takes its geometry from: racking, the collector width of the Racking tab and this section's height above ground, transparent fraction and structure shading factor; or pvwatts_layout, the fixed values of PVWatts version 8: the slope length of 300 W modules with a length 1.7 times their width (1.638 m on a tracker and 3.277 m on a fixed rack for the standard type, 1.683 m and 3.367 m for thin film), 1 m above ground, a transparent fraction of 0.013 and no structure shading. The Model tab's Rear-side geometry step sets it.

Typical values and how to get it

racking for a design; pvwatts_layout to reproduce PVWatts version 8. If not given: racking.

References

  1. NREL SAM Simulation Core (SSC) source code, release 2026.7.3, github.com/NatLabRockies/ssc: ssc/cmod_pvwattsv8.cpp, the representative module's geometry and the rear irradiance in exec() (calc_rear_side(0.013, 1, module.length · nmody), passed to the module model without a mismatch)

API

bifacial.geometry