PVWatts V8 and pvsamv1 are generating different simulation messages for bifacial modules with non-zero tilt and one-axis tracking.
pvsamv1:
Subarray 1 uses bifacial modules with one-axis tracking and a tilt angle of 20 degrees. The bifacial model is designed for one-axis tracking with a tilt angle of zero and may not produce reliable results for non-zero tilt angles.
PVWatts:
The tilt angle is 20 degrees with one-axis tracking. Large one-axis tracking arrays typically have a tilt angle of zero.
The bifacial model is designed for fixed arrays and may not produce reliable results for tracking arrays.
The bifacial model is similarly accurate for tracking systems as for fixed-tilt systems. There may be small nuances the model misses with tilted tracked systems because “it assumes infinite same effects on that axis” but that results should be quite similar.
Suggest removing messages.
See https://sam.nrel.gov/forum/forum-general/3285
PVWatts V8 and pvsamv1 are generating different simulation messages for bifacial modules with non-zero tilt and one-axis tracking.
pvsamv1:
Subarray 1 uses bifacial modules with one-axis tracking and a tilt angle of 20 degrees. The bifacial model is designed for one-axis tracking with a tilt angle of zero and may not produce reliable results for non-zero tilt angles.
PVWatts:
The tilt angle is 20 degrees with one-axis tracking. Large one-axis tracking arrays typically have a tilt angle of zero.
The bifacial model is designed for fixed arrays and may not produce reliable results for tracking arrays.
The bifacial model is similarly accurate for tracking systems as for fixed-tilt systems. There may be small nuances the model misses with tilted tracked systems because “it assumes infinite same effects on that axis” but that results should be quite similar.
Suggest removing messages.
See https://sam.nrel.gov/forum/forum-general/3285