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Heating and Cooling load components: a detailed breakdown

asked 2021-09-28 14:26:54 -0500

Beny1396's avatar

updated 2021-09-28 16:53:08 -0500

Hi all,

I hope everything is going well with you. I am working on a small office building's energy evaluation project implemented in the OpenStudio application, and I need to analyze the heating and cooling loads (I am using the Ideal Air Loads option, so there is no designed HVAC system). What I am specifically looking into is: what is the contribution of each component to the hourly heating and cooling loads? For example, assuming that the hourly heating load for February 5th at 2:00 PM is 20J, how much is due to the heat conduction from opaque walls, internal gains due to people's activity, etc. I looked into different reports such as annual sensible heat gain components and zone component load summary (this one gives the values for peak loads only). I have also used the envelope and internal load breakdown, but they are only monthly and annual gains and losses, so it is not what I am looking for. Do you recommend any other solution?

Thank you very much in advance for your help.

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2 Answers

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answered 2021-10-05 15:03:35 -0500

obuchely's avatar

Hi. You can use ladybug tools.

link text

The work flow is a bit different but you can get the results that you are looking for.

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Specifically, the Thermal Load Balance component, as seen here: Once Ladybug is downloaded, there's a sample script that shows how to use it.

saeranv's avatar saeranv  ( 2021-10-06 10:34:12 -0500 )edit

Hi. Thank you very much for your information. I saw in the post that the load breakdown was for peak loads, and I hope I can modify it to account for the hourly loads, as well. Given that I am not familiar with the ladybug, which one do you recommend? Honeybee in Grasshopper platform or other types? Thanks again for your kind help and consideration.

Beny1396's avatar Beny1396  ( 2021-10-06 14:13:17 -0500 )edit

The Thermal Load Balance provides a monthly breakdown of hourly loads from an annual simulation, not peak loads (there's a separate component for that). Honeybee in Grasshopper/Rhino contains the most mature, robust workflows in LBT, so I would advise using that.

saeranv's avatar saeranv  ( 2021-10-06 15:27:31 -0500 )edit

Hi again, thanks for your comment. I have installed Honeybee, but when I try to import my idf file, the system crashes. Do you have any recommendations? Should I start re-developing the model in Honeybee from scratch? Thanks again.

Beny1396's avatar Beny1396  ( 2021-10-07 12:21:52 -0500 )edit

Yeah importing an idf file might have errors. I've never run into errors building the model from scratch in Honeybee (as long as the library is installed properly). If you run into errors building the HB model you can ask questions on the LBT forums: To partially confirm you got the installation right, make sure your OpenStudio installation is consistent with the LBT compatibility matrix here:

saeranv's avatar saeranv  ( 2021-10-07 12:47:27 -0500 )edit

answered 2021-10-26 10:28:17 -0500

Hi! A good tool to analyze hourly outputs is Results Viewer (can be downloaded from DesignBuilder webpage for free). It doesn't provide a load breakup automatically, you need to add outputs you deem relevant (e.g. based on the RDD file) to your IDF, and these can be analyzed in Results Viewer, that can open ESO files.

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Asked: 2021-09-28 14:26:54 -0500

Seen: 278 times

Last updated: Oct 05 '21