EnergyPlus setting heat transfer algorithm for constructions - leads to fatal error

asked 2022-07-26 08:54:41 -0500

AGeissler
93 ●1 ●6

updated 2022-07-26 16:52:17 -0500

Aaron Boranian

14070 ●81 ●24 http://bigladdersoftware.com/

Hi there,

does anyone have experience in setting the heat transfer algorithm of selected constructions? According to the IO-Manual, I can set the global behaviour via

HeatBalanceAlgorithm, ConductionTransferFunction, 200; !- Algorithm, Surface Temperature Upper Limit {C}

and can then change this for selected constructions like this,

SurfaceProperty:HeatTransferAlgorithm:Construction, BO05Override, ConductionFiniteDifference, BO05; !- Name, Algorithm, Construction Name

Seems easy & straightforward. However, I then get a fatal error when trying to run the simulation telling me that "InitialInitHeatBalFiniteDiff: Found Material that is too thin and/or too highly conductive ..." which gives a material name that is not part of the construction addressed.

Any ideas welcome. Best Achim

OS: macOS; EnergyPlus, Version 22.1.0-43b09606e2

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Can you provide a link to your IDF via, e.g., Google Drive or Dropbox?

shorowit ( 2022-07-26 17:11:23 -0500 )edit

Hi Scott, thanks for taking notice. The .idf should be downloadable from here for a few days: https://drive.switch.ch/index.php/s/Q.... Best, Achim

AGeissler ( 2022-07-27 03:06:53 -0500 )edit

I'm not an expert in this area but, having looked briefly at your file, I agree with you that the error message is either wrong or confusing. I suggest creating a new issue at https://github.com/NREL/EnergyPlus/is....

shorowit ( 2022-07-27 09:50:24 -0500 )edit

Hi Scott, thanks again, finally I found time to re-compile the current version of E+ (there seemed to be some commits in the general area of my problem). Sadly, to no avail. So now I created a new issue (#9597) as you suggested. Let's see what happens. Best, Achim

AGeissler ( 2022-08-11 07:20:50 -0500 )edit

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answered 2022-08-15 14:06:53 -0500

RKStrand
106 ●2

This is definitely a problem and is being worked on. When you selected the CondFD solution, that triggered an initialization routine specific for that solution technique. The problem occurred in part because you used regular materials for the air layer rather than Material:AirGap. The CondFD code was basically going through all constructions and even ones that were not using the CondFD solution. That included one that had your air layer in it and this caused a problem. If you had used the air gap input rather than the regular material input, it would have skipped this and you wouldn't have gotten an error message. So, that is a temporary work around--change your air layer definitions to Material:AirGap. The full fix is to skip constructions that are not used for CondFD and that is what is being worked on. Hope this helps!

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Workaround suggested works fine. Thanks again (by the way, the original "culprit" material was a sheet metal, not an air layer). A kind of "follow-up" question: I now am able to look at construction node temperatures, however, it is quite tedious to enter an output line for each node for a given construction, especially as the number of nodes changes w/ time-step used. Any tricks here? Thanks.

AGeissler ( 2022-08-31 08:58:21 -0500 )edit

You can use regular expressions in the output variables you request, see here for example.

shorowit ( 2022-08-31 10:24:26 -0500 )edit

Sadly it seems no. Regex only seem possible in the "first" category, i.e. here the surface name. Not in the variable name. At least, I couldn't find any example that does that and my own trials all led to (fatal) errors. The input-for-output looks like this: Output:Variable,Surface 328,CondFD Surface Temperature Node 34,Timestep; so the regex would need to be something like this Output:Variable,Surface 328,CondFD Surface Temperature Node .*,Timestep; which does not seem to work.

AGeissler ( 2022-08-31 10:34:33 -0500 )edit

Ah, you're probably right. You might consider requesting at https://github.com/NREL/EnergyPlus/is... that the regex be expanded to output variable names, though that won't help your immediate need.

shorowit ( 2022-08-31 11:13:21 -0500 )edit

I submitted issue #9632.

AGeissler ( 2022-09-01 01:34:10 -0500 )edit

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EnergyPlus setting heat transfer algorithm for constructions - leads to fatal error

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EnergyPlus setting heat transfer algorithm for constructions - leads to fatal error