Get Autosized IDF File (After Sizing Runs)

asked 2017-11-22 22:28:15 -0500

bbrannon4
1715 ●1 ●2 ●15

updated 2017-11-23 08:05:15 -0500

Julien Marrec

29077 ●86 ●74 http://www.effibem.com/

I'd like to run a simulation that has several values being autosized, but then get an idf file out that is exactly the same, but has the autosized values hard entered. EnergyPlus must have those values to be able to run, but I don't know if it's ever in an IDF format, or they are just adding in after the input file has been processed. If the former, then there must at least be a temporary file somewhere that would serve my needs, right?

This is related to this previous question, but hopefully with a different answer: use autosizing values for next simulations.

answered 2017-11-23 08:18:36 -0500

Julien Marrec

29077 ●86 ●74 http://www.effibem.com/

(I'm not sure if I should answer this question since I think it's exactly the same question as the one linked except you ask about an "intermediate IDF", but here it is anwyays)

No, there isn't an "intermediate IDF" file with the autosized values. What E+ does is two fold:

If autosize, it autosizes it during the run of the program and uses that in subsequent calculations
It also exports it for review

The autosized values are for example stored in the eplusout.sql file (if you request it), so you could use a script to fetch and replace them.

openstudio-standards actually uses this logic to apply sizing values to the model, see for yourself:

If you dig a mininum in the code base of openstudio-standards, you'll realize it's a lot of work to define it for every possible type of component (and it's actually not implemented for a bunch of components right now, the ones that aren't mandatory for baseline generation).

So if you only want to get a few autosized values (say for any Boiler:HotWater of Chiller:ElectricEIR only), then a quick python script querying the SQL file is the way to go, couple that with eppy for eg.

If you want to do it for a ton of components, a good idea might be to use OpenStudio with openstudio-standards.

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FWIW, methods to get all autosizable fields in all objects supported by OpenStudio should be included in OpenStudio 2.4.0, including a method to apply all autosized values back to the model.