While comparing Surface Sunlit Fraction across different surface types, I’m seeing physically impossible values for Shading:* surfaces and PV-panel host surfaces (used by Generator:Photovoltaic). Specifically: During timesteps when the sun is below the horizon (Site Solar Altitude Angle < 0 and Site Sun Is Up = 0), Surface Sunlit Fraction for Shading:* and PV surfaces is non-zero and sometimes exceeds 1.0.

In the same timesteps, Surface Sunlit Fraction for BuildingSurface:Detailed and FenestrationSurface:Detailed is correctly 0.0.

Operating System (Multiple choices)

Windows

Operating System Version

11

Version of EnergyPlus

23

Unmethours link or helpdesk ticket number

N/A

Defect file

File to reproduce the issue:
Shoebox.idf.txt