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OS/E+ Autosizing Error for Hot Water Unit Heaters

asked 2015-04-06 10:09:27 -0600

updated 2020-03-08 11:28:05 -0600

I am getting the following error with hot water unit heaters in OpenStudio. The weird thing is that with OS was using E+ 8.1 I would not get this error, but with the updated OS that runs E+ 8.2 I am getting an error. It seems to be from zones that have zero heating load (such as an internal stairwell) that have unit heaters placed in them. Has anyone else had this issue, and does anyone know a way to fix it? I have tried hard sizing the unit heaters, and messing with the plant setting to no avail.

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I'm surprised that hard sizing doesn't work around this problem. Are you sure you hard sized the actual coil:heating:water object inside the unit heater?

Kyle Benne's avatar Kyle Benne  ( 2015-04-06 14:01:12 -0600 )edit

Yes I hard sized the actual coil design capacity and it did not fix the issue. Also, I do not want to have to hard size all of my unit heaters and for a large project this might happen to 20+ coils and I don't want to have to run OS 20 times to track down all of the coils with this issue and hard size them. I was hoping to find a solution that could be applied to all unit heaters in my model.

TaylorRoberts's avatar TaylorRoberts  ( 2015-04-06 14:37:08 -0600 )edit

Has anyone else ran into this issue?

TaylorRoberts's avatar TaylorRoberts  ( 2015-04-09 09:27:51 -0600 )edit

@TaylorRoberts curiously I am in the midst of updating OpenStudio to EnergyPlus 8.3 and while running the test suite I suddenly see this exact error popping up on a hot water coil that is inside AirLoopHVACUnitarySystem. No amount of fidgeting with the plant sizing has yet alleviated the issue. I can reduce the size of the coil, therefore reducing the load on the plant and make the problem go away, but I haven't been able to get the plant to match the coil I have. I'll keep you posted as I work through this.

Kyle Benne's avatar Kyle Benne  ( 2015-04-14 12:09:21 -0600 )edit

Hi Taylor. Did you ever figure out this problem? I'm having the same issue.

mleach's avatar mleach  ( 2015-06-19 18:09:11 -0600 )edit

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answered 2015-07-24 16:52:26 -0600

This has been documented as an E+ issue here.

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Asked: 2015-04-06 10:09:27 -0600

Seen: 221 times

Last updated: Jul 24 '15