OpenStudio-designed AirLoop leading to EnergyPlus crash

asked 2015-08-10 07:36:57 -0500

updated 2015-08-20 14:21:14 -0500

After importing an osm-file Version 1.4.0 into OpenStudio 1.8.0, in the HVAC air-loop the setpoint manager symbol is lost, as displayed in the following image: image description

But this apparently was not the real problem: Starting a simulation run leads to an EnergyPlus crash, with an err-file of zero size. If the osm-file is exported to an idf-file and this idf-file is used to start a simulation, EnergyPlus also crashes. After some investigation I found that in the OS-exported idf-file there was no DesigSpecification:OutdoorAir object, although such objects exist in the osm-file version. After inserting a DesigSpecification:OutdoorAir object plus zone sizing references to this object, the EnergyPlus simulation was running without fatal error.

My initial diagnosis is that Openstudio does not create proper zoneHVAC sizing outputs for EnergyPlus (apart from the lost setpoint manager symbol bug) and there is also a bug in EnergyPlus which does not recognize the exception.

I have sent you the osm crashing file via email. OS Version: 1.8.0 /EP 8.3.0 (Windows 7, 32bit)

Update: MJWitte has meanwhile confirmed: The problem is that there are no DesignSpecification:OutdoorAir objects present in the idf. Contray to what the Input Output Reference states about the Design Specification Outdoor Air Object fields in Controller:MechanicalVentilation, there are required inputs. Same is true for DesignSpecification:ZoneAirDistribution (but these are present in this file, so they aren't a problem). New issue posted, #5112.

Dear OpenStudio development team: is this enough to post also a new bug-fix issue on the part of OpenStudio ?

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Comments

Thanks for the bugs! Did the model run in 1.4.0, but then not run in 1.8.0? Trying to determine whether it was a problem in updating the file, or whether it was an issue that has likely been fixed between 1.4.0 and 1.8.0. Also, the missing SPM icon bug is filed here

aparker ( 2015-08-20 15:51:28 -0500 )edit

I have sent you the osm files in both versions, so you can do further tests. However, I have realized meanwhile that in the 1.4.0 version osm-file (and subsequently the imported 1.8.0-version) did not contain a Design Specification Outdoor Air object. This could be considered a user error, but while this object appears to be optional in OpenStudio, it is apparently mandatory in EnergyPlus for sizing and it lead to crashes.