Override Outdoor Air

[spakkala]

Does anyone know if there is a way to override the outdoor air for a zone? I have all my spaces set up correctly based on our current mechanical code. But depending on the air distribution, the effectiveness is different and thus the outdoor air needs to be adjusted accordingly. When I do a heating and cooling load, there is a spot for outdoor air information, but it is not adjustable. It is set on the space type. Or perhaps there is another way to add more outdoor air? This is a big limiting factor in the heating and cooling load software unless I am missing something.

Thank you!

[dtiemeyer]

I'm not familiar with the load calcs inside Revit, but you can add parameters to a space schedule and create additional parameters that modify your current results. I guess it boils down to where you need the data to exist and what it's downstream use is.  In this scenario I've only modified the schedule to include a new Number parameter that gets added to the outside airflow, but it could easily be a percentage. This data only shows up on the schedule. If you needed it to be a property of the space itself, you could create a shared parameter that becomes a project parameter applied to spaces, then schedule all of them, then use a formula like this. 

[spakkala]

Thank you.

I already have something similar to this that does this calculation already. The issue is in the heating and cooling loads. It won't take these percentages. It only brings in the values based on the space type properties. Essentially 100% and not any sort of factor can be applied short of changing the values in each space type (which would then mess up my schedule). 
Example: I set all my space type properties to a certain value, and the minimum outdoor air comes out to be 2000 CFM. Based on the air distribution, the effectiveness is 80%, which brings my required outdoor air to 2500 CFM. When the outdoor air can be -20 degrees, this affects the overall heat load quite a bit. Revit's heating and load calc will only consider the 1000 CFM and thus the load is undersized. There isn't a way to override this value for the heating and cooling loads as near as I am aware.