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EnergyPlus Number of Output Variables Limitation

asked 2017-01-31 08:28:37 -0500

updated 2017-01-31 09:37:29 -0500

I made a very large model with more than 200 thermal zones. I found an issue when I request more than one output variables in E+, it will only report one variable in the excel output.

Is this because an limitation within EnergyPlus for number of reporting zones?

Now I have to run several parallel simulations to request more variables which is very time consuming.

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There should be no limitations. Did you initially create an rvi file and forget to update it?

rraustad gravatar imagerraustad ( 2017-01-31 08:48:53 -0500 )edit

There might be one limitation (maybe that's outdated though): the number of columns (=N_variables - 1) used to be limited to 256 (old Excel versions - 2003 and older - had such a limitation of max 256 columns, now it's 16,384). There's an option in the EP-Launch parameters to discard any warning message and allow more than 250 columns. See the VB source code for EP-Launch here

But if you get exactly ONE variable (not one per zone), I'd think this is a different problem.

Julien Marrec gravatar imageJulien Marrec ( 2017-01-31 08:53:34 -0500 )edit

@Julien Marre . How should I use those VB source code for EP-launch. Thank you very much for the quick response. For example I only requested zone lighting and electrical equipment,so I will be more than 500 columns.

Bo_Lin gravatar imageBo_Lin ( 2017-01-31 09:02:40 -0500 )edit
1

Related post (that I forgot I ever wrote...): Calling ReadVarsESO without the 255 columns limit

Julien Marrec gravatar imageJulien Marrec ( 2017-01-31 09:02:55 -0500 )edit

(I gave you the VB code because I don't have EP-Launch handy, doesn't exist on mac...) In EP-Launch, go to Options, and find this option to "Allow more than 250 columns" and check it. Then rerun sim. Are you getting ONE variable now, or ONE per zone? Stated differently, how many columns do you have in your csv output now?

Julien Marrec gravatar imageJulien Marrec ( 2017-01-31 09:03:50 -0500 )edit

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answered 2017-01-31 09:17:38 -0500

updated 2017-01-31 09:18:20 -0500

Problem cause:

There is an option in EP-Launch, I believe disabled by default, to allow more than 250 columns. In reality, it's actually 255 variables + one column header that gives 256 columns. So by default the CSV output generated by ReadVarsESO has maximum 256 columns.

This is due to the - now completely outdated - inner limitations of Excel. Indeed, before Excel 2007, you could only have 256 columns.

+-----------------+-----------+--------------+
|                 | Max. Rows | Max. Columns |
+-----------------+-----------+--------------+
| Excel 365*      | 1,048,576 | 16,384       |
| Excel 2013      | 1,048,576 | 16,384       |
| Excel 2010      | 1,048,576 | 16,384       |
| Excel 2007      | 1,048,576 | 16,384       |
| Excel 2003      | 65,536    | 256          |
| Excel 2002 (XP) | 65,536    | 256          |
| Excel 2000      | 65,536    | 256          |
| Excel 97        | 65,536    | 256          |
| Excel 95        | 16,384    | 256          |
| Excel 5         | 16,384    | 256          |
+-----------------+-----------+--------------+

(Source of table: superuser)


Solution:

In EP-Launch, Go the options, and find "Allow More Than 250 Columns" and check the box (I believe it sits under "Miscellaneous" according to the source code).


Side notes:

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Comments

Should this question be closed?

JasonGlazer gravatar imageJasonGlazer ( 2017-02-01 06:59:21 -0500 )edit

Indeed no, so I reopened it. I think the general ability to close for reason "this question is answered, right answer was accepted" doesn't make sense. (unless the question was answered by a one-liner in the comment box maybe...)

Seeing "[closed]" in the title always makes me think the question has a problem and not worth my attention.

Marking the answer as accepted is sufficient to mark the thread as resolved.

Julien Marrec gravatar imageJulien Marrec ( 2017-02-02 02:04:51 -0500 )edit

My bad, didn't find how to accept the right answer at that time.

Bo_Lin gravatar imageBo_Lin ( 2017-02-02 08:19:59 -0500 )edit

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Asked: 2017-01-31 08:28:37 -0500

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Last updated: Jan 31 '17