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Hot water tank cannot be autosized without failing, is there a way around hard sizing?

asked 2016-03-06 01:03:53 -0600

VictoriaEagen's avatar

updated 2016-03-06 07:37:52 -0600

I created a Water Use Connections object and a Water Fixture object and dropped them into the appropriate places in the Service Hot Water Loop. I then attempted to bring the hot water to the loop. I dropped a mixed hot water tank into the demand side of my district hot water loop. I created a new plant loop and dropped the same hot water tank into the supply size and added my water connection to the demand side. When I dropped the hot water tank in it hard sized to a really large value and my water use equipment was 95% of the usage of my building. I then tried to autosize and it failed. Is this a common bug? Is there a way around this?

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Can you add the error message and version of OS you're using?

MatthewSteen's avatar MatthewSteen  ( 2016-03-06 07:39:32 -0600 )edit

I think it's the same error as discussed on the tracker [here] ( @Julien Marrec seems to have recently encountered this as well in 1.10.2.

Adam Hilton's avatar Adam Hilton  ( 2016-03-06 13:52:04 -0600 )edit

It is OS 1.9.0.

VictoriaEagen's avatar VictoriaEagen  ( 2016-03-07 21:38:09 -0600 )edit

1 Answer

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answered 2016-03-22 07:46:25 -0600

This is currently a bug in OpenStudio as @adhilton mentioned. Here are two workarounds:

  1. Hard size the tank volume

  2. Write an EnergyPlus Measure to add the WaterHeater:Sizing object at run time.

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Asked: 2016-03-06 01:03:53 -0600

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Last updated: Mar 22 '16