Is there a way to simulate for natural ventilation through earth duct in the new versions of LB/ HB?

I found these components to simulate for the use of earth ducts in the old version, however, the rest of my script for thermal simulation is in version 1.6,how I add these as a part of the script now to account for an earth duct in the design.

I found this issue listed on the forum earlier in these links listed below, but I’m struggling to understand it.

Do I have to model a room under the main building model, that is considered as an earth duct or should I just add the string to simulate for it?

Please help me with incorporating earth ducts into my thermal simulation script (which is a multizone model). Thank you in advance.
@MichaelEsposito @chris @AbrahamYezioro @mostapha @angelo.figliola @MassimilianoBusnelli @AntonSzilasi @fn

Hey @deepthi.ravi ,

You have brought up the only energy simulation Legacy component for which we don’t have an equivalent LBT workflow beyond “use additional IDF strings”, “write your own measure” or “post-process the OSM exported from Honeybee using the OpenStudio SDK inside a Python component like the sample you see here”.

I was wondering if anyone was going to bring this up just because, these days, most situations where people would go through the effort of digging out a trench for an earth tube or thermal labyrinth, they would sooner use that excavation effort to put in a ground source heat pump. You just tend to get a lot more control over the thermal conditions this way and you can better take advantage of the heat capacity of the earth by circulating water instead of air. The LBT plugin has some pretty good support for GSHP systems through the HVAC templates and all of the customization you can do in Ironbug (as I’m sure you’ll see on the forum here if you search for it).

But, if I can’t win you over to the side of suggesting GSHPs over earth tubes and you tell me that you would use an earth tube component if we were to add it to LBT, then I’ll put it on our development agenda. If other people confirm that they want it, then I’ll bump up the priority of it.

And, if you tell me this is the one thing that is stopping you from upgrading from Legacy, then I’ll see if I can hack together a component for you that generates some “additional IDF strings” so that you can use it with your LBT workflows.

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Hi Chris
Thank you for your response.

The strategy for this project is to use both earth ducts and GSHP, purely because earth ducts are considered more of a semi-passive strategy and therefore would have lower active loads compared to GSHP, and hence reducing overall energy usage, if I’m not wrong.

I’m willing to work with an additional IDF string for this, where I apply it to the input at add_str, however, since my model is a multizone model, I wasn’t sure how to consider this into the string. Should I instead take only the zone that the outlet from the earth duct leads to?

Hey @deepthi.ravi ,

I don’t really remember what the IDF strings for earth tubes should look like since @AntonSzilasi did this development in the Legacy plugin. I remember there was some EnergyPlus pre-processing utility that was supposed to be run as part of the process.

If you upload a sample Grasshopper file with how far you’ve gotten, I’ll try to take a look and see if I can help when I get the chance.

Please find the attached grasshopper file. (1.1 MB)