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OpenStudio CLI Design Days

asked 2022-08-30 08:02:56 -0600

mattkoch's avatar

updated 2022-08-30 08:54:30 -0600

I am trying to make more use of the openstudio cli. In this context, I am using the workflow file .osw. In it, there is a line for the weather file, such as:

"weather_file": "E:/WeatherData/USA_TX_College.Station-Easterwood.Field.722445_TMY3/USA_TX_College.Station-Easterwood.Field.722445_TMY3.epw"

However, I have not seen the equivalent for the design day file, for example, does something like the following exist for the workflow file .osw:

"designday_file": "E:/WeatherData/USA_TX_College.Station-Easterwood.Field.722445_TMY3/USA_TX_College.Station-Easterwood.Field.722445_TMY3.ddy"

If not, what are the alternatives? Thanks.

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answered 2022-08-30 08:59:39 -0600

If you want to use an existing measure in your workflow, the ChangeBuildingLocation measure expects the .ddy file to have same name as the .epw file. The .epw file name with extension is taken as a measure argument.

If you are writing your own measure, this line inspects the .ddy file

ddy_model = OpenStudio::EnergyPlus.loadAndTranslateIdf(ddy_file).get

And this line adds a design day object into the OpenStudio model. If you look at code above this we are importing a subset of design days from the file.


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Yeah, I just noticed the JSON Workflow documentation knows no such thing as ddy, so I suppose a measure it has to be. The ChangeBuildingLocation will get me what I need, though, thanks.

mattkoch's avatar mattkoch  ( 2022-08-30 09:12:30 -0600 )edit

@mattkoch, I forgot to mention more straight forward approach. I'm always sweeping across climate zones so I forgot this. While the OpenStudio model links to EPW data, the design days are ingested into the model, so the source .ddy isn't needed as run time. So you can choose a seed model to define in the OSW that already has design day objects. Then you don't need the ChangeBuildingLocation measure.

ChangeBuildingLocation also uses that .stat file to set water main temperatures, and sets the ASHRAE climate zone, useful if you plan to use OpenStudio Standards to assign construction

David Goldwasser's avatar David Goldwasser  ( 2022-08-30 09:52:24 -0600 )edit

Brilliant, than you David Goldwasser. Very helpful!

mattkoch's avatar mattkoch  ( 2022-08-30 16:50:11 -0600 )edit

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Asked: 2022-08-30 08:02:56 -0600

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Last updated: Aug 30 '22