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The volume flow rate on AFN only while heating in EnergyPlus

asked 2020-08-23 03:19:57 -0500

juhyun Bak gravatar image

updated 2020-08-23 03:22:51 -0500

Currently, I can get results using 'Zone Air System Sensible Heating Rate' and 'AFN Linkage Node 2 to Node 1 Volume Flow Rate' in my model in E+.

However, can I report the value of the volume flow rate only under the heating condition from the CSV file?

In other words, is it possible to report the airflow rate only when the heating rate is not zero? What is the way?

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We need some more information to answer your question.

  • What AFN Control are you using?
  • What kind of HVAC system are you modeling?
  • Do you want to report the airflow rate in the HVAC system when the heating rate is not zero, or report airflow rate everywhere (infiltration, inter-zone mixing, etc.) when the heating rate is not zero?
Aaron Boranian gravatar image Aaron Boranian  ( 2020-08-23 07:41:38 -0500 )edit

Thanks for your comment.

  • I'm using 'Multizone Without Distribution' .
  • I'm using 'HVAC Template: Zone: Ideal Load Air System '.
  • I want to report the airflow rates everywhere (infiltration, inter-zone mixing, etc.) when the heating rate is not zero.
juhyun Bak gravatar image juhyun Bak  ( 2020-08-23 20:46:40 -0500 )edit

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answered 2020-08-23 17:14:44 -0500

I do believe that there are going to be ways to do this within EnergyPlus (probably involving EMS), but I'm not sure that what you've described is going to be worth all of the effort that's going to be needed. Unless I am misunderstanding your question, I'd think that the easiest way to do this would be to postprocess the CSV and break the airflow rate column into two columns, one with a nonzero heating rate and one with a zero heating rate.

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Thanks for your answer.

I just want to know the amount of airflow when the heating load is not zero.

Although data postprocessing can be carried out in Excel after deriving the heating load as output and airflow rate as output, it is difficult to do postprocessing work due to deriving data per hour for one year and conducting simulations under various climatic conditions.

Do you know how to make this work easier using EMS?

juhyun Bak gravatar image juhyun Bak  ( 2020-08-23 20:45:11 -0500 )edit
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I would do it with Python as opposed to Excel, Python's CSV module makes this sort of thing super easy. I'm no EMS expert, so I could be terribly wrong, but here's what I'd try with EMS. Output variables can be scheduled (see the I/O Ref, 5.1.12.1.4 Field: Schedule Name), so you could put a schedule on the 'AFN Linkage Node 2 to Node 1 Volume Flow Rate' output variable(s) and then use EMS to override the schedule. That is described in section 8.5 of the EMS application guide and in the EMSCustomSchedule.idf example file. I can't say for certain that it would work, but I think it should.

Jason DeGraw gravatar image Jason DeGraw  ( 2020-08-23 22:34:40 -0500 )edit

Thanks for your answer.

juhyun Bak gravatar image juhyun Bak  ( 2020-08-27 02:39:09 -0500 )edit

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Asked: 2020-08-23 03:19:57 -0500

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Last updated: Aug 23 '20