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Severe node connection errors but not fatal - do they matter?

asked 2014-11-26 05:27:01 -0600

updated 2015-07-11 18:46:09 -0600

I have a model with a solid oxide fuel cell CHP included. The example file MicroCogeneration.idf I have adapted it from has a PTAC but my modelled building does not so I've removed it. I think the issue that EnergyPlus is flagging up in the .err file is that there are dangling connections where the PTAC was previously.

Have I understood this correctly? Do these errors matter? And if they do, how do I prevent them? The model runs anyway so it seems like this may not be an issue but I'd like to confirm one way or the other.

Extract from the .err file:

************* Testing Individual Branch Integrity
************* All Branches passed integrity testing
************* Testing Individual Supply Air Path Integrity
************* All Supply Air Paths passed integrity testing
************* Testing Individual Return Air Path Integrity
************* All Return Air Paths passed integrity testing
** Severe  ** Node Connection Error, Node="BUILDING:SAPZONE2 INLET NODE", ZoneInlet node did not find an outlet node.
**   ~~~   ** Reference Object=ZONEHVAC:EQUIPMENTCONNECTIONS, Name=BUILDING:SAPZONE2
** Severe  ** Node Connection Error, Node="BUILDING:SAPZONE2 EXHAUST NODE", ZoneExhaust node did not find a matching inlet node.
**   ~~~   ** Reference Object=ZONEHVAC:EQUIPMENTCONNECTIONS, Name=BUILDING:SAPZONE2
************* There were 2 node connection errors noted.
************* Beginning Simulation
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answered 2014-11-26 09:21:00 -0600

Archmage gravatar image

Yes, I think your understanding is correct. To prevent them, alter the ZoneHVAC:EquipmentConnections object so it no longer includes the inlet and outlet/exhaust nodes that were in there for the PTAC. The errors may not matter much as long as you know the equipment is missing.

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I have a similar situation with an IDF generated in OpenStudio: I had deleted a setpoint manager, but there are evidently still e+ nodes that reflect its presence (same severe error in the ERR output). But the model runs and makes sense, so I have been inclined to leave it alone, since I'm avoiding editing at the IDF level.

Nick N gravatar image Nick N  ( 2015-07-23 12:38:32 -0600 )edit

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Asked: 2014-11-26 05:27:01 -0600

Seen: 383 times

Last updated: Nov 26 '14