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How can I add precipitation data in OPENSTUDIO?

asked 2018-12-21 05:10:41 -0500

alepelu92's avatar

updated 2020-01-20 12:09:18 -0500

Hi everyone, it’s been a few days since I am trying to solve this problem but I didn’t find a way yet, so I hope that you can help me 😊

I am studying the performance of a green roof on a building using Openstudio but I didn't find a way to add precipitation data in the software. I've seen that there is the possibility to add precipitation data through the object Site:Precipitation in Energyplus, but I don't understand then how can I import these data in Openstudio. Is there a way to import the precipitation data set in Energyplus in Openstudio or another way to add precipitation data in Openstudio? I’ve seen that someone suggested to apply Energyplus measure in Openstudio but I didn’t really understand how to do it and if it works. I want to run a simulation of my building and see the results in openstudio, so I am not interested in evaluating it in Energyplus. Do you have any suggestion? thank you so much :)

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answered 2018-12-21 12:18:56 -0500

You can use the existing Inject IDF objects EnergyPlus measure on the OpenStudio Building Component Library to accomplish this. In the OpenStudio application, go to the Measures tab, and add this EnergyPlus measure. For the measure, you will supply a path to a IDF file where only the Site:Precipitation object (and perhaps a Schedule object referenced by it) are in the file.

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Thankyou so much! I found the E+ measure and defined an IDF that contains only the precipitation object and its schedule, but when I tried to add the path to the IDF file in this measure I got some errors such as "Error:Cannot load" or "Error:Doesn't exist". I think that I am writing the path wrong. I put in the path field the path found in the IDF file properties, but I am wondering that the format is not the right one. How does the path that I should add in the path field in “Inject IDF objects” measure look like? The path that I pasted in OS is \Users\aless\OneDrive\Desktop\Precipitation.

alepelu92's avatar alepelu92  ( 2018-12-27 05:46:09 -0500 )edit

Try using forward slashes instead: /Users/aless/OneDrive/Desktop/Precipitation

shorowit's avatar shorowit  ( 2018-12-27 08:56:24 -0500 )edit

And just to confirm, "Precipitation" is the name of the IDF file, right? You might rename it to "Precipitation.idf" to be clearer.

shorowit's avatar shorowit  ( 2018-12-27 08:57:05 -0500 )edit

answered 2018-12-21 11:50:25 -0500

It doesn't look like you can define the Site:Precipitation object's parameters in the Openstudio interface. The available methods to add this to your building energy modeling project are:

  1. Export the IDF (EnergyPlus input file) from OpenStudio, add the Site:Precipitation object to the exported IDF, then run the IDF directly in EnergyPlus. This requires more work, doesn't allow you to view OpenStudio results (monthly bar charts of energy use, zone conditions summary, etc.), and should only be done if you are done with setting all input parameters in OpenStudio. If you update a parameter in OpenStudio, you have to redo the export IDF and add precipitation object process.
  2. Use a measure. There are three categories of measures: OpenStudio, EnergyPlus, and Reporting. You can use an OpenStudio measure if the object you want to add or change is in the OpenStudio SDK. It does not look like the Site:Precipitation object is part of the SDK. In this case, you will need to use an EnergyPlus measure to "inject" the Site:Precipitation object into the model when you simulate.

There is a free resource managed by NREL (developers of OpenStudio) called the Building Component Library. You can search here to see if there is an existing measure you can download and use. Unfortunately for you, no measures are found if you search for "precipitation" or "rain". So, it looks like you will need to write your own EnergyPlus measure to add precipitation if you want to use method 2 instead of method 1 outlined above. Which sounds like the case, from your original post.

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Asked: 2018-12-21 05:10:41 -0500

Seen: 884 times

Last updated: Dec 21 '18