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How to simulate natural ventilation between interzones using operable windows/doors?

asked 2021-02-03 21:28:11 -0600

MDR gravatar image

updated 2021-04-05 09:51:47 -0600

The case study I am trying to simulate is basically 4 individual rooms/apartments that are connected by a corridor. Sliding windows are opened in each room, and doors of each room are opened. The corridor does not have windows, so air runs through the room windows - exits through room doors - flows through the corridor and then enters through another room door and exit through a window. I want to use natural ventilation to predict the mean indoor air temperature of each room/apartment under those conditions (then validate by comparing results with data that was already collected in situ). The rooms/apartments are located in the 20th floor of an apartment building of total 32 floors. I am using coupled simulation using SketchUp OS plugin and OS app. I already tried using this Natural ventilation measure - which describes that is not intended to be use for interzone modeling. I used this measure and created a construction material for operable windows - and assigned it to one side of the sliding window of each room and to the doors. Not all windows from the rooms are operable - some are fixed too; and doors are operable. However, I do not know if results are accurate - because the measure does not calculate interzones. With this background information. How would you simulate the natural ventilation between interzones using operable windows/doors? Thank you.

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For this complex cases of natural ventilation I´d recommend looking into the Airflow Network. The AFN needs to be implemented via Energyplus directly, since it is not supported by OS yet.

You can find some examples inside your Energyplus folder installation inside the folder ExampleFiles

rafael.alonso gravatar image rafael.alonso  ( 2021-02-04 09:05:20 -0600 )edit

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answered 2021-02-08 02:09:00 -0600

LaCuterina gravatar image

I did something similar modelling a greenhouse with operable windows based on a daily schedule I used the Airflow Network module as you suggested but get alway a Severe Error because zone has no surface in Airflow Network:Surface Obviously there are, I listed there all zone surfaces (windows, walls, floors...) Sincerely I have not clearly understood which surfaces shall be listed here, but the error says no surfaces at all. I appreciate your help Thanks

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Hi @LaCuterina, can you share your idf file or some images of your current AFN part of the script?

In general, you need at least 2 surfaces per zone included in the AirflowNetwork:Multizone:Zone class. Not all the zones in your model need to be included as AirflowNetwork:Multizone:Zone, just those that you wish to be part of the ventilation path.

rafael.alonso gravatar image rafael.alonso  ( 2021-02-09 03:15:24 -0600 )edit

Hi @rafael, sorry for late reply but I had to finalize my work. I don't know exactly how I solved this issue, but I redesinged the skup model completely and then, following the input/output guide, I succeded. Still have some warnings regarding geometry but no severe errors But, once results shown up, I noted an insanely ach (around 300 air change rate per hour) And really cannot understand where it comes from. Here you have some screenshots. Maybe you can see something that's really invisible for me. thanks for the guide I will read it carefully

LaCuterina gravatar image LaCuterina  ( 2021-02-14 09:22:35 -0600 )edit

The issue could be related to the AFN Effective Leakage Area objects. Have you tried adjusting the Discharge coefficient? Depending on the type of opening, this could range between 0.3 to 0.8 or so. You can check this to get a better idea:

If yours are operable windows, I´d recommend using the DetailedOpening object to have finer control over the inputs.

rafael.alonso gravatar image rafael.alonso  ( 2021-02-15 03:25:14 -0600 )edit

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Asked: 2021-02-03 21:28:11 -0600

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Last updated: Feb 03 '21