Using your excellent “HB Load Energy Model” component, I am finding that I obtain this abstruse error when I try to load any of the Energy Plus Airflow Network idf Example files:
Solution exception:Failed to run OpenStudio CLI: Cannot load IDF file at ‘’
I am considering suggesting that students in a Positive Energy class mine the EnergyPlus Example Files for the application of technologies like PV, Thermal Chimneys, Heat Recovery etc. The goal is to introduce them to the technologies, and to modelling them, plus also understanding how we can learn from others’ documented approaches.
This is looking promising as I assign them a script like that attached:
I would also add that the E+ example files for Shop with SimplePVT and ThermalChimney have materials in them that trigger a warning in your energy model importer that might need a second line of logic: they contain models of ultra-thin highly-conductive materials that cannot be imported.
As always, any thoughts or suggestions about this approach greatly welcomed.
HI @MichaelDonn
The error “Failed to run OpenStudio CLI: Cannot load IDF file at ‘” is related to the version of E+ which created the idf file. You’are using LBT 1.5 so you can install E+22.1 and do a test with one of the differents examples idf files.
AndyK
As I read it: OpenStudio still does not handle Airflow Networks because the developers are focused on a very corporate, large building, view of the world which sees Natural Ventilation as a minor issue. LBT gets around this somehow while still essentially building an .osm model.
So, if I wish to find a Heat Recovery Ventilation example file to import as part of my class, I should not use any of the E+ AFN files as the import energy model component in LBT must be using at least some of the functionality of the OS import approach which produces (in Open Studio) this error:
Bear in mind that AFN cannot imported from IDF files but you can always set up your Honeybee models to use the AFN like the sample that you see here. Only geometry, boundary conditions, constructions, schedules and loads are imported. HVAC, SHW and AFN are too complex to be imported easily.
Your IDF without the AFN imports and simulates fine on my end:
Coming back to teach the same class - the next year. In this I am focused on students learning how to script by mining the LBT sample files, and my own example file.
Last year, this was symptomatic of the problems that arise from using the EnergyPlus example file dataset as a source of examples to learn from. I plan to avoid the issue this year.
I had hoped to encourage the students to take apart the EnergyPlus sample files they were importing into LBT once they were running. However, far too many of them would run in E+ but not in LBT/Open Studio. Sometimes the errors were material properties (e.g. thickness) which generated an OS error, but ran fine in E+. Apart from AFN, there was IceStorage, Night Ventilation, Earth Tubes, HAMT modelling, Solar collectors, Photovoltaics, Trombe Walls, and so on and on. The goal was enabling them to see how to look beyond LBT for what they might learn about the Energy Conservation Measures they read about in books.
Just recording for posterity that the apparently sensible “Import IDF” run and graph option after selecting a promising model from the 100s of E+ example files seems like a dead end…
I just wanted to say I agree with you, @MichaelDonn . EnergyPlus has a huge number of objects for simulating practically any energy conservation strategy you want but most of them are so specific that it’s just not practical for us or NREL to write translators that can import them to OSM or Honeybee world. Not only is it just an enormous task to attempt to import all of what E+ offers but it’s almost certainly going to compromise the reliability of the translator if any of those thousands of object changes its IDF schema with a new version of E+.
If you really wanted to teach your students about how to model custom and specific energy conservation strategies, I think a “bottom-up” approach that went from a Grasshopper-built honeybee model and then applied an E+ strategy via additional strings would be much better than attempting to go “top-down” with the EnergyPlus sample files. So you could have your students build a base Honeybee model, then research a highly-custom strategy they want by studying the EnergyPlus Input Output Reference (eg. evaporative cooling towers), then have them try to add IDF text to their models to simulate the strategy. Granted, different strategies will require different levels of complexity to implement this way and students will have to be comfortable with text editing to pull this off so it may not be for everyone. But that’s the best strategy I can think of if you want the students to feel empowered to edit and explore the world of IDF.
