[Solved] ExportToOpenStudio vs runEnergySimulation - Results differences

Thanks, Abraham. You’ve found the issue already. Let’s see if Chris has any comments on this. I’ve overbooked myself for the next two weeks but hopefully I can take a look after that if it’s still an issue.

Thanks Mostapha.

Crossing fingers this is the reason and it is easy to fix.

BTW, from the image above we can see that in OS, the only double connection happens between z6 and z7, while there is a missing connection between z3 and z6.


Abraham and Mostapha,

Thank you very much for finding the error. I have what I need to fix it now and I am sorry that I am just getting around to it now. I’ll post back here in an hour with fixed components.



Man, this bug was like finding a needle in a haystack! It was just one little line that needed changing but the bug only affected cases where you have several air walls between zones, which made it so hard for me to replicate on a smaller scale. It really required a file of this size and created surface-by-surface to replicate.

To be clear, the bug was in the OpenStudio component in that it was only writing out a single mixing object for each zone instead of the multiple objects needed to model cross-mixing of air in between zones.

This bug has been fixed here:


… and in the attached file.

Thank you again, Abraham and Mostapha, for your persistence with addressing this issue. As they say, any computer issue is solve-able with enough perseverance. I am happy to finally say that this case is closed!


munotoA115.09.16ASHRAEEU_AY_Updt_FIXED.gh (1.95 MB)

Great news Chris!!

I’ll check it, but i’m sure it going to be fine.

As you know this case is very important for me and my student, and it was necessary to solve, otherwise phasing towards the OS was not going to be possible, not now and not later.

It was indeed hard to find, and this is another lesson that you always need to check ALL the outputs. In this case the IDF files which are the output of the components, to understand they are well written.

Thanks again,



This is official. Issue solved == case closed.

Results are exactly the same.

Thanks a lot. This was a tough one.


Great job both! As always impressed by both of you, on finding the issues and get them fixed. I hope to finally break out of the butterfly strike in the next few days and check this out.