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Openstudio Run Time

asked 2014-11-20 08:59:09 -0500

Jlerazo gravatar image

updated 2015-01-19 03:04:16 -0500

I am developing a model of a large office building in Open Studio 1.4. It has 1000 spaces and 15 story. The problem is the run time. The simulation delays 7 - 9 hours. How can I fix it?

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answered 2014-11-20 09:08:50 -0500

Assuming that many of the stories are the same, you could use zone multipliers. See the answers to this question for more info on zone multipliers in OpenStudio.

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In addition to the zone multipliers you can try to minimize the number of spaces you use. You also seem to have about 65 space per floor which is probably more than necessary. Another run-time gottcha with EnergyPlus is running the simulation on a network drive. Make sure you are running to a local hard dive.

David Goldwasser gravatar imageDavid Goldwasser ( 2014-11-20 09:26:43 -0500 )edit

thank you for your answer, but I am detailing each story because is my graduation project and I must include the information.

Jlerazo gravatar imageJlerazo ( 2014-11-20 09:29:24 -0500 )edit

Good energy modeling does not necessarily mean modeling each detail as it exists physically. Floor multipliers, ribbon windows, and combined spaces are all valid approaches to producing a model that adequately reflects end uses while running in a reasonable time. Hopefully your instructor appreciates a pragmatic approach to modeling.

ljbrackney gravatar imageljbrackney ( 2014-11-20 10:04:57 -0500 )edit

I have not been performing my project with Software Trainer, I've developed by trial and error, then when I did the model have been learning what works and what does not.

Now I make the necessary changes to my model resembles reality, but want to know the impact of changes, and that I should further adjust

Jlerazo gravatar imageJlerazo ( 2014-11-20 10:36:05 -0500 )edit

answered 2014-11-21 11:25:54 -0500

@Jlerazo You said 1000 spaces, but you did not say how many thermal zones. Most users assume that fewer zones will speed up the simulation, but this can be counterproductive in large models. One of the biggest run-time hits can be the internal thermal radiant exchange within a zone where every surface exchanges with nearly every other surface. For a simple zone with 6-12 surfaces, this calculation goes quickly. For a zone with 100s or 1000s of surfaces, the computation time to solve the matrix grows geometrically (I may not have the right growth term, but you get the point). Other considerations are the number of surrounding shading surfaces, the selected solar distribution option in the building object, the quantity of output, daylighting, thermal comfort models (KSU model is slow), etc.

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Hi!, thank for your answer. My model have 24 thermal zones, the building have 15 stories (HVAC=Chiller), and there are others spaces where the hvac equipment works independent, like cocktail lounge or auditorium.

The model have 1134 spaces, 9733 surfaces and 1009 subsurfaces. Referent to the shading surfaces, I am not considering it. Respect to the selected solar distribution option in the building object, the quantity of output, daylighting, thermal comfort models (KSU model is slow), could you share me some link for read how apply it en OS?

Jlerazo gravatar imageJlerazo ( 2014-11-21 12:03:58 -0500 )edit

Jlerazo Sorry I did not notice your comment earlier. So, for a model like this, using more thermal zones should make it run faster by reducing the number of surfaces per thermal zone.

MJWitte gravatar imageMJWitte ( 2014-12-08 15:29:03 -0500 )edit

answered 2014-11-20 09:36:09 -0500

@Jlerazo. Simulation time is an EnergyPlus characteristic, not an OpenStudio one. OpenStudio can help you set up a simpler model that EnergyPlus will run faster, but if you really need to simulate every space and zone, then you are 99% stuck. The 1% is that you may be able to get onto Autodesk's new EnergyPlus Cloud beta (, which will use temporal parallelization to run your model about 10X faster. There may be a few other packages that can do this too, but I am not sure how many of them are available as services and what kind of computing resources are available to you if they are not. Good luck!

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@Amir Roth, he should do your winter break project for quicker runs while developing the model, with full access to full model for final runs :)

If you have more time, here are more projects.

  • spring break project - convert punched windows to ribbon windows
  • summer break project - merge adjacent co-planer surfaces in same zone that have the same constructions and same boundary conditions.
David Goldwasser gravatar imageDavid Goldwasser ( 2014-11-20 09:44:30 -0500 )edit

Thanks, I already have used the OSM diagnostic, now I am setting my model to the real condition, because in my model I have different occupancy per story. I am running the simulation, for check if the energy consumption is approaching for the real.

Jlerazo gravatar imageJlerazo ( 2014-11-20 10:11:40 -0500 )edit

answered 2015-02-13 10:35:52 -0500

Krishnan gravatar image

updated 2015-02-13 11:18:35 -0500

This is caused by truncated IDF input for certain objects from OpenStudio IDF, passed through the version updater. We fixed this error two weeks ago and tested it to be working well. The runtime is just a bit less than 10 minutes for this model that we received. If you are still havng problems, please send us the original idf (post it to the Autodesk Labs forum) before sending it through the version updater and we will revisit this issue. Its a challenge to find out all the quirks of how IDF is authored by various tools. Kudos to EnergyPlus team that they can handle most of this gracefully !!

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answered 2015-01-16 12:40:39 -0500

Jlerazo gravatar image

updated 2015-01-16 12:43:19 -0500

@Amir Roth, I am trying to use the Cloud, I have access to input my files, but I have not been able to run the simulation successfully. I always get the error:

Program Version,EnergyPlus, Version 8.2.0, YMD=2015.01.16 13:10,IDDVersion 8.2.0
** Severe
** IP: IDF line~146133 Did not find "10HeatBalanceAlgorithm" in list of Objects ** Severe ** IP: Possible incorrect IDD File ** ~~~ ** IDD Version:"IDD
Version 8.2.0" * ~~~ * Version in IDF="8.2" not the same as expected="8.2" * ~~~ * Possible Invalid Numerics or other problems * Fatal * IP: Errors occurred on processing IDF file. Preceding condition(s) cause termination. ...Summary of Errors that led to program termination: ..... Reference severe error count=2 ..... Last severe error=IP: Possible incorrect IDD File *** Warning: Node connection errors not checked - most system input has not been read (see previous warning). *** Fatal error -- final processing. Program exited before simulations began. See previous error messages. *** EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors. *** EnergyPlus Sizing Error Summary. During Sizing: 0 Warning; 0 Severe Errors. *** EnergyPlus Terminated--Fatal Error Detected. 0 Warning; 2 Severe Errors; Elapsed Time=00hr 00min 1.29sec

Have you try to use the cloud? or do you have any procedure to use the IDF file generated for OS?

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@Jlerazo. It looks like there is an EnergyPlus version mismatch between your OS version and EP-Cloud. What version of EnergyPlus is your OS producing?

__AmirRoth__ gravatar image__AmirRoth__ ( 2015-01-16 12:48:23 -0500 )edit

@Amir Roth, the E+ is the V8.1 (used with OS 1.5), but when I send the file, I change the version to V8.2 with the EnergyPlus Version Updater. I don´t know if before to sent the IDF i have to change something in the file, please could you guide me how use correctly the cloud?

Jlerazo gravatar imageJlerazo ( 2015-01-16 13:38:11 -0500 )edit

@Jlerazo. Will your file run on your own machine?

__AmirRoth__ gravatar image__AmirRoth__ ( 2015-01-17 09:01:35 -0500 )edit

@Amir Roth. Yes, I have run my model in a laptop with E+ v8.2. The same file I send to the cloud.

Jlerazo gravatar imageJlerazo ( 2015-01-17 11:55:16 -0500 )edit

@Jlerazo. OK, then you need to contact Autodesk's EP-Cloud support.

__AmirRoth__ gravatar image__AmirRoth__ ( 2015-01-17 12:11:29 -0500 )edit

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Asked: 2014-11-20 08:59:09 -0500

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Last updated: Feb 13 '15