EnergyPlus Crashes When Adding Windows to Rotating Building Model Using Site:VariableLocation
I have been experimenting with the Site:VariableLocation object in EnergyPlus to simulate a rotating building where orientation changes dynamically (e.g., monthly). To test it, I started with the VaryingLocationAndOrientation.idf example file and modified it to represent a simple building with windows instead of a vessel with "underwater" boundary conditions (idf v9.1 can be found here link text).
At first, EnergyPlus kept crashing during simulation with a blank .err file. After some debugging, I found that removing the FenestrationSurface:Detailed objects allowed the simulation to run without crashing. I tried substituting with the Window object too, but it was still crashing. It seems that there could be a conflict between dynamic orientation and solar/optical calculations for transparent surfaces but not opaque surfaces?
Testing using EnergyPlus v25.1:
Interestingly, when testing the same setup in EnergyPlus v25.1, the simulation only crashes if more than one window is present. If there's just a single window, the simulation runs without crashing. To explore this further, I compared the output variable "Surface Outside Face Incident Solar Radiation Rate per Area [W/m2]" between two cases: one with a fixed 90° orientation using the Building object, and another with a 90° dynamic rotation using Site:VariableLocation. The results for the surface hosting the window surface showed significant differences between the two cases. However, when the window was removed (i.e., all surfaces are opaque), the results aligned better suggesting that the dynamic orientation may not be consistently applied to fenestration surfaces.
Also, I noticed something potentially confusing in the example file: the field order appears to be shifted compared to the IDD documentation. For example, the name field is being used to pass a schedule for latitude.
Site:VariableLocation,
VaryingLatitude, !- Name
VaryingLongitude, !- Building Location Latitude Schedule
VaryingOrientation, !- Building Location Longitude Schedule
; !- Building Location Orientation Schedule
Has anyone:
- Confirmed if this is a known limitation or bug?
- Used
Site:VariableLocationwith windows successfully? or found a workaround?
Thanks!




EnergyPlus should never crash. And I can confirm the Name field is being incorrectly ignored, it's in the IDD/documentation but not the IDF sample file. I don't see any existing bug reports about this object, so please issue a bug report at https://github.com/NREL/EnergyPlus/is...
Thanks for the response. I created this issue: https://github.com/NREL/EnergyPlus/is...