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EnergyPlus : json.exception.type_error.305

asked 2020-01-18 20:47:50 -0500

rezaei2's avatar

updated 2020-01-19 12:08:23 -0500

Hello, I'm working with a template VAV in EnergyPlus and after a simulation I have this message for error ' json.exception.type_error.305' Do you know what's this error? I can't find the problem. Thank you,

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Can you provide more details please? What version of EnergyPlus? Can you post a snippet from the error file around this error message, or better yet, post the entire error file? Can you post your IDF file since that error message appears to be one that is likely a bug in EnergyPlus itself?

MarkAdams's avatar MarkAdams  ( 2020-01-19 13:23:47 -0500 )edit

The version of EnergyPlus is "V9-2-0".Program Version,EnergyPlus, Version 9.2.0- The details of error is "Program Version,EnergyPlus, Version 9.2.0-921312fa1d, YMD=2020.01.18 22:41, * Severe * [json.exception.type_error.305] cannot use operator[] with a numeric argument with null * Fatal * Errors occurred on processing input file. Preceding condition(s) cause termination. ...Summary of Errors that led to program termination: ..... Reference severe error count=1 ..... Last severe error=[json.exception.type_error.305] cannot use operator[] with a numeric argument with nul'l

rezaei2's avatar rezaei2  ( 2020-01-20 23:50:40 -0500 )edit

I tried to post the IDF file but it 's not possible. I can send that by email.

rezaei2's avatar rezaei2  ( 2020-01-20 23:55:08 -0500 )edit

To upload an IDF file here you need to change the file extension to .txt You can also submit a ticket through EnergyPlus Helpdesk (

MarkAdams's avatar MarkAdams  ( 2020-01-21 08:21:52 -0500 )edit

Ok, Thank you Mark. I submited the ticket. Ticket ID #15382

Type Issue Priority Medium

Subject: json.exception.type_error.305

VAV Sys idf

Is this enough? Please let me know, I did correct or not.

rezaei2's avatar rezaei2  ( 2020-01-21 11:22:32 -0500 )edit

1 Answer

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answered 2020-03-06 15:33:27 -0500

The EnergyPlus input processor is failing, because one of the objects generated by HVACTemplate is incomplete. Examining the expidf output file, reveals the problem:

ExpandObjects,                                           !- Preprocessor Name
Fatal,                                                   !- Error Severity
Severe:  In HVACTemplate:Plant:ChilledWaterLoop "Chiled Water Loop" there,  !- message line
is one or more water cooled chiller(s) but there are no towers serving this,  !- message line
loop.;                                                   !- message line

So, this file can be fixed by adding a cooling tower, or by changing the chiller to aircooled. But with that fixed, it still won't run, because a hot water loop is specified, but there are no hot water coils to be serve in the air handler or terminal units.

An issue has been posted to better protect what gets written to the expidf so that preprocessor errors can make it through to the EnergyPlus err file now with the stricter input processing that was introduced a few versions ago.

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Asked: 2020-01-18 20:47:50 -0500

Seen: 468 times

Last updated: Mar 06 '20