Simulation time with complex external shading

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@LyleK, we've done some work on the shading calculations in the current iteration and they have sped up significantly, although I am not sure whether the 15,000 surface limit for overlap calcs is still there. I believe these changes are already in the main EnergyPlus "develop" trunk (@Edwin?). If you are feeling adventurous, you could build your own EnergyPlus from source. Come on, what else do you have going on this weekend? :)

By default EnergyPlus mirrors shading surfaces at runtime. That may be important for vertical fins, but if your shading surfaces are horizontal then you can turn this off. It might also be nice to see an image of the model to see why there are so many surfaces.

• Are you doing a lot of site shading of adjacent structures? If so make sure to only draw shading surfaces that face your structure or would directly affect the shading. If these adjacent structures have tiny little undulations in plan, you may consider drawing it as a flat plane instead.
• Do you have tons of punched windows each with their own shade? If so you could consider window or zone multipliers. Although not sure how using a window multiplier would affect the sunlit fraction of the base surface, since it would only have one shade vs. one for every window. Would take some thought.
• Back to not mirror shading surfaces, I'm not exactly sure if that is something in the IDF or through EP Launch. Would take some work to see how to set that for an OpenStudio run.
• The calculation frequency is a good suggestion. That is available in OpenStudio in the simulation settings. We default to 30.

You might also look at your timestep in general too see if it can be relaxed, and also see what solar distribution you need for your model.