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Can we use epjson as input file to run energy simulation?

asked 2019-01-10 18:47:43 -0500

katsuya.obara's avatar

I understand that EnergyPlus is planning to use epJson as input/output file.
However, when I open EP-launch.exe in v9.0.1 which I use to run EP file usually, seems I cannot select json file as input file.
Are there any documentation which explain how I can use epjson file as input to EP-launch or CLI?
Also, are there any converter available from idf file to epjson and vice varsa?

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answered 2019-01-11 08:55:58 -0500

updated 2024-03-04 13:16:16 -0500

If you call the EnergyPlus CLI with the -h flag, it will display all options:

C:\EnergyPlusV22-1-0\energyplus.exe -h
EnergyPlus, Version 22.1.0-ed759b17ee, YMD=2022.05.05 09:35
Usage: energyplus [options] [input-file]
  -a, --annual                 Force annual simulation
  -c, --convert                Output IDF->epJSON or epJSON->IDF, dependent on
                               input file type
--convert-only                 Only convert IDF->epJSON or epJSON->IDF,
                               dependent on input file type. No simulation
Example: energyplus -w weather.epw -r input.idf

The --convert-only option is used to generate an epJSON file from an IDF (and vice versa). So you can do:

C:\EnergyPlusV22-1-0\energyplus.exe --convert-only in.idf

and it will output the in.epJSON file.

Then you can run the epJSON file like so:

C:\EnergyPlusV22-1-0\energyplus.exe in.epJSON

Alternatively, you can use the --convert or -c option to do both steps (convert the file and run the simulation) at the same time:

C:\EnergyPlusV22-1-0\energyplus.exe -c in.idf

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Hi, this Q/A is somewhat old, but I expect it is still basically true (except that there is a new option --convert_only to avoid running a simulation for .idf-to-.epJSON conversion). A question, though: is the -r in above example necessary or does EnergyPlus take .epJSON files basically as equivalent to an .idf? Also, I suppose a -w <climate> is necessary in conjunction with the .epJSON, as well, if in.epw is not available/to be used.

AGeissler's avatar AGeissler  ( 2022-05-05 06:42:25 -0500 )edit

Thanks, I have updated the answer to include the new --convert-only option. As to your questions about -r and -w, the easiest answer is to just try it and see!

shorowit's avatar shorowit  ( 2022-05-05 10:41:03 -0500 )edit


The command above with the "-r" option will not run the simulation. "-r" is short for --readvars, which runs ReadVarsESO after simulation.

To simply run the simulation, the command is:

C:\EnergyPlusV22-1-0\energyplus.exe in.epJSON
ericmartinpe's avatar ericmartinpe  ( 2024-03-04 12:42:13 -0500 )edit

The -r is an optional argument that can be used; I agree that it doesn't run the simulation. I'll remove it above since it's clearly causing some confusion.

shorowit's avatar shorowit  ( 2024-03-04 13:15:39 -0500 )edit

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Asked: 2019-01-10 18:47:43 -0500

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Last updated: Mar 04