When I run the Energy Plus simulation it comes up with this error. "DetermineShadowingCombinations: There are 3 surfaces which are casting surfaces and are non-convex. * ~~~ * ...Shadowing values may be inaccurate." I am not sure how to resolve this issue and what it means exactly.
A casting surface is one that produces a solar shadow on another surface. The shading model in EnergyPlus does not work well for non-convex casting surfaces. You can change a surface from non-convex (or concave) to convex by breaking it up into a set of smaller component surfaces that are each convex.
This issue has been added to the EnergyPlus project requesting support for non-convex casting surfaces. This issue was added to request clarification on this warning output, right now it is somewhat confusing as it is labelled a severe error but the simulation completes and produces results. I think if the first issue were addressed then the second issue becomes unnecessary as there is no more error.
Does anyone know, does this error actually affect the simulation results? Are the results from a simulation with this error still valid?
It definitely affects the results (to the bad). From the Engineering Ref: "During surface entry, surfaces are checked for convex or non-convex shape. If non-convex and inappropriate (used as a receiving surface) then a severe error is produced telling the user that shadowing calculations may be inaccurate."
Sorry @Archmage , I didn't understand how to change a surface from non-convex (or concave) to convex. Could you please explain it with more details ? I am not really familiar with that concept (of convex surface) and I am new in using openstudio sketchup plugin
Thanks :)
Hello, I found this video From NREL which might be useful :-)
Youtube - Finding non-Convex Surfaces with the OpenStudio SketchUp Plug-in
Cheers, Juanita
Excellent! Thank you Juanita!
Asked: 10 years ago
Seen: 4,640 times
Last updated: Mar 18 '20
@eklein12 in the future please tag your question with the software you're using, it'll get a faster response that way. Are you also using OpenStudio?
Sorry, I will do that in the future. Yes I amusing Open Studio.
I think this is a duplicate of this question: Non-convex surfaces in EnergyPlus
I think you're right @Julien Marrec. @eklein12, does the previous question help?
Yes, I have been able to fix the severe error with the non-convex surfaces. Thank you.