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OS Required Hourly Outputs and Reporting Time

asked 2016-03-29 17:54:08 -0500

Does OpenStudio automatically create hourly output variables for Zone Air Temperature and Zone Air Relative Humidity? These output variables are marked as 'OFF' on the output variables tab of my OS model, and I don't see them defined as objects in my OSM file either. However, when I run a simulation and open the ESO output file, I see hourly temperature and humidity results for every zone in my model.

Question 1: Is OS plotting these variables (behind the scenes) for every run so it can pull values for OS summary reports? Is there a way I can turn these off when running an OS simulation?

Possibly related to this, I've noticed it can take an additional 5-10 minutes for the entire 'OS simulation' to finish after a successful 'E+ simulation' is reported in the run tab of OS. After the 'E+ simulation' completion message is displayed in the OS run tab, I believe E+ is still creating reports and then OS is parsing those reports when complete.

Question 2: Is there a way to cut down post E+ simulation time for my OpenStudio run?

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answered 2016-03-30 01:50:45 -0500

Yes, by default OpenStudio adds these two output variables. It's actually because of the standard reporting measure. To produce the tables of zone conditions where you see number of hours in humidity range and temperature range for each zone, it needs to request this output.

And yes, it can slow down your runtime quite significantly. While the reporting measure is really nice, if you're just debugging or going through an iteration to calibrate or something, then I suggest you turn it off and wait until you're satisfied to enable it back again.

Currently there's no proper way to turn off the reporting measure but I've posted a hack that works here

As far as other things to cut simulation time, the obvious places to look for at the timestep value (defaults to 6, but 4 can be plenty no?), the solar distribution, the convergence limits, etc.

Also, if you're doing an annual simulation, make sure you turn off "Run for sizing periods". I've noticed that people get confused by this, they think turning it off will result in a failure of sizing. What it means is whether or not it'll run the simulation and report the variables. If you have 7 design days, that means 7 more runperiods in your SQL file, also means 7 warmup periods more... That takes a lot of time.

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Thanks for confirming the temperature and humidity variables are created automatically and used for the zone condition tables. I will try to modify/disable the report measure as suggested...somehow I missed the post you are referencing when I was searching Unmet Hours previously. Very helpful as always, Julien.

Lyle K's avatar Lyle K  ( 2016-03-30 11:07:46 -0500 )edit

I'm aware of the steps you mention to reduce the E+ sizing and energy simulation time (timestep, solar calcs, convergence, etc...). I was looking for ways to cut down on the reporting time when I'm building and QC'ing large models. I've found that the 'reporting magic' can add an additional 25-33% to my complete OS runtime.

Lyle K's avatar Lyle K  ( 2016-03-30 11:16:16 -0500 )edit

I've had a similar experience... That's why I didn't give up until I found a way to disable the measure (as much as I love it overall! It's really nice, once your model is running ok)

Julien Marrec's avatar Julien Marrec  ( 2016-03-30 11:38:56 -0500 )edit

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Asked: 2016-03-29 17:54:08 -0500

Seen: 295 times

Last updated: Mar 30 '16