Setting Ground Temperature in OS

Hi all,

I'm modelling a simple house with few thermal zones with OS 2.7.0, but in order to correctly simulate its thermal behavior the correct ground temperature must be informed, otherwise EnergyPlus will assume its default monthly temperature (18C) which isn't correct.

It's very much like this question: https://unmethours.com/question/11228...

Through an answer In this thread I've noticed that OS already has Site:GroundTemperature:BuildingSurface Model Object but I can't find it anywhere.

Could someone explain how to get it into my model?

Thanks

BrunoRaviolo

asked 2019-09-29 14:00:12 -0500

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Aaron Boranian

updated 2024-08-26 08:12:51 -0500

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I've had this issue too and I didn't understand the answers so i searched for a ground temperature measures in open studio and got this unhandled exception which crashed my program " Provide URI is invalid: /api/metasearch/groundtemperature.xml? fq%5B%5D=bundl:nrel_measure&fq%5B%5D=tid:953&api_version=2.0 "

TheEnergyTutor (2020-05-26 09:50:02 -0500) edit

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I am guessing you are looking for the object in the OpenStudio Application, as far as I know it has not been added to the application yet. You can add the site ground temperature to the model by using an OpenStudio measure. The documentation for this object is here

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Saif

answered 2020-05-23 13:08:12 -0500

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need more detailed instructions on how to add this to OS

TheEnergyTutor (2020-05-26 12:32:32 -0500) edit

you will need to write a measure which is a script in Ruby programming language, you can find more details about the measure writing in the OpenStudio documentation here

Saif (2020-05-26 13:25:06 -0500) edit

Myself and my co-workers are engineers, not computer programmers. I don't see this happening as we already have full plate with what we do.

TheEnergyTutor (2020-05-26 14:01:47 -0500) edit

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This BCL measure will allow you to set monthly ground temperatures: https://bcl.nrel.gov/content/a7048e34...

A youtube video describes it here: https://youtu.be/GO5RU8ccfs4?si=j5KUJ...

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Ski90Moo

answered 2024-08-26 06:28:44 -0500

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After simulating with OpenStudio, you can set up the Site:GroundTemperature:BuildingSurface in EnergyPlus. For buildings in a hot region, the ground temperature can be set to 24 to 26C for summer months, 16-18C for winter months, and decreasing temperatures for other months.

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TianZhichao

answered 2020-05-23 04:02:03 -0500

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but how do we do it?

TheEnergyTutor (2020-05-26 12:33:05 -0500) edit

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For those looking still for a answer on this. You need to do it by the use of scripts. In my case I have created one to use inside SketchUp Ruby Command. Here it is what I use:

require 'openstudio'

# Read the open model
model_interface = OpenStudio::Plugin.model_manager.model_interface
model = model_interface.openstudio_model

ground_temperatures = [10.0] * 12  # 12 months, all at 10ºC (change it for your input)
site_ground_temp = OpenStudio::Model::SiteGroundTemperatureBuildingSurface.new(model)
site_ground_temp.setAllMonthlyTemperatures(ground_temperatures)

Applying it you will see the following on energyplus default report: image description

On the other hand I recommend you having a look at CFactor and FFactor boundary conditions. They can be more precise methods for ground surfaces in contact.

Hope it helps :)