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Trying to find a complete object list for E+

asked 2016-12-15 17:49:06 -0500

NickC gravatar image

updated 2016-12-16 09:38:58 -0500

Can anyone guide me to a complete list of energyplus objects for v8.4, v8.5, and v8.6? Aside from the documentation on Big Ladder, I haven't located this list yet. I did check the E+ Github, release notes, and E+ wiki.

I'm looking for something that could be easily incorporated into a database.

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C:\EnergyPlusV8-5-0\ExampleFiles\ExampleFiles-ObjectsLink.html ? (same for 8.4 and 8.6.)

Chandan Sharma gravatar image Chandan Sharma  ( 2016-12-15 19:43:50 -0500 )edit

How about the Energy+.idd file? I would guess that there's a tool out there to parse it and write a list of the objects to file. Maybe eppy or the OpenStudio API?

MatthewSteen gravatar image MatthewSteen  ( 2016-12-15 20:22:56 -0500 )edit

Thanks for the quick suggestions! Both would do the trick; the object link is easier. I'm also looking for the required inputs for each object so the *.idd covers that as well. But I can't choose an answer! ;)

NickC gravatar image NickC  ( 2016-12-15 20:33:32 -0500 )edit

@NickC I'll let you answer your own question since I don't know for sure that my suggestions will work, but please share how it goes!

MatthewSteen gravatar image MatthewSteen  ( 2016-12-15 22:12:53 -0500 )edit

@NickC you can try IddFileAndFactoryWrapper.

ngkhanh gravatar image ngkhanh  ( 2016-12-16 00:34:51 -0500 )edit

1 Answer

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answered 2017-01-09 17:15:49 -0500

updated 2017-01-13 03:20:58 -0500

Option 1: Python, using eppy:

In [1]:
import eppy.EPlusInterfaceFunctions.parse_idd as parse_idd

iddfile = "/Applications/EnergyPlus-8-6-0/Energy+.idd"

x = parse_idd.extractidddata(iddfile)

useful = x[2]

The most useful (IMHO) is the second element of the 4-tuple x

That's a list of each idd object, each idd object being a list of dict where the first element (index 0) is the object itself, and the following are each field.


In [2]: useful[6]
[{'format': ['singleLine'],
  'group': 'Simulation Parameters',
  'idfobj': 'SurfaceConvectionAlgorithm:Inside',
  'memo': ['Default indoor surface heat transfer convection algorithm to be used for all zones'],
  'unique-object': ['']},
 {'default': ['TARP'],
  'field': ['Algorithm'],
  'key': ['Simple', 'TARP', 'CeilingDiffuser', 'AdaptiveConvectionAlgorithm'],
  'note': ['Simple = constant value natural convection (ASHRAE)',
   'TARP = variable natural convection based on temperature difference (ASHRAE, Walton)',
   'CeilingDiffuser = ACH-based forced and mixed convection correlations',
   'for ceiling diffuser configuration with simple natural convection limit',
   'AdaptiveConvectionAlgorithm = dynamic selection of convection models based on conditions'],
  'type': ['choice']}]

Here's a way you would print each object and their fields (there's much more info) for the first few objects of the idd

In [3]:
for k in useful[2:5]:
    for j in k[1:]:
        print("---- {}".format(j['field'][0]))

---- Version Identifier
---- Do Zone Sizing Calculation
---- Do System Sizing Calculation
---- Do Plant Sizing Calculation
---- Run Simulation for Sizing Periods
---- Run Simulation for Weather File Run Periods
---- Do HVAC Sizing Simulation for Sizing Periods
---- Maximum Number of HVAC Sizing Simulation Passes
---- Name
---- North Axis
---- Terrain
---- Loads Convergence Tolerance Value
---- Temperature Convergence Tolerance Value
---- Solar Distribution
---- Maximum Number of Warmup Days
---- Minimum Number of Warmup Days

Option 2: Ruby, using OpenStudio

This will print each object and its field, as well as save it into a hash (key = idd object name, value = list of fields)

h = {}

factory ="EnergyPlus".to_IddFileType)
factory.objects.each do |obj|
  n = obj.numFields
  l = []
  obj.nonextensibleFields.each do |field|
    puts "---- #{}"
    l <<
  if l.length < n
    puts "ERROR, missing fields"
  h[] = l

Of course you can access more info out of each field, for example,,, etc, etc

Option 3: using the new JSON input dictionary (JDD), using either Python or Ruby

E+ 8.7 release is in preparation and will include a new "JDD" for JSON input Data Dictionary, the JSON equivalent of the IDD. Currently this is on a separate development branch, but here's the input_processor_refactor/idd/

I'm gonna propose a Python and a Ruby version to parse this file, print the fields for each object as well as store a simple dict/hash where the key is the object type, and the value is a list of the fields for each object. Of course, there's way more information in the JDD, use it as you want.

3.a Python

import json
import urllib.request 

jdd_url ...
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Thanks @JasonGlazer for adding the Option 4 (IDF editor), wiki style!

Julien Marrec gravatar image Julien Marrec  ( 2017-01-10 07:52:06 -0500 )edit

I was going to make another answer but you already had some options listed so I added another one.Thanks for putting together your answer!

JasonGlazer gravatar image JasonGlazer  ( 2017-01-10 09:59:07 -0500 )edit

@Julien Marrec Thanks for the excellent and detailed answer! The new JSON idd is exciting and I'm following that development now on Github as well.

NickC gravatar image NickC  ( 2017-01-16 14:53:53 -0500 )edit

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Asked: 2016-12-15 17:49:06 -0500

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Last updated: Jan 13 '17