HB Shade - Duplicate name error

I need help setting up window shades/awnings. This model works with one window/shade, but as soon as I go to two I get the following error in the HB Annual Loads:

** Severe ** Duplicate name found for object of type “Shading:Zone:Detailed” named “Shade_1402de41”. Overwriting existing object.

Awning Test.3dm (140.4 KB)
Awning Test.gh (57.4 KB)

The issue is you are trying to apply two shades to two different windows at once. Honeybee can’t tell which window to apply which shade so it applies both shades to both windows, causing a duplication.

You would need to apply each shade to their respective windows individually in order for the model to run.

Thanks @kentakahas. Is there a way to do this without making a new component for each window? In reality I’m modeling a building with many more windows.

You have to use datatrees to match the data.

Thanks @mostapha. It looks like graft gets rid of the error. Is this correct?

That use of data trees looks like it should work correctly.

FYI, another way of doing this if you just want to generate some overhangs is to use the HB Louver SHades component.

Or you could just not assign the shade to the individual windows and just connect them to the shades_ input of the “HB Annual Loads” component.

Both of those options above will give you the same result as what you have here but will be much less prone to accidental duplication.

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Perfect, using HB Louver Shades is much easier @chris!

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One more question: When I increase the awning length from 0 to 1 meters, the solar load and cooling demand decrease as expected. However the heating demand also decreases slightly. Do you know why this would be? I would expect the heating demand to increase with more shading.


Awning Test.3dm (135.4 KB)
Awning Test.gh (72.3 KB)

My best guess is because of the desert climate with pretty clear skies, the overhangs are preventing radiative heat loss to the cold skies at night.
Looking at the hourly comparison, you can see the no shade (blue) has a higher heating load during the winter night hours, and a negligible decrease during the day compared to the overhang case (red).


Good detective work, @kentakahas ! That seems like a reasonable explanation to me and EnergyPlus is certainly capable of accounting for this type of radiant heat exchange with the sky (including the effect that the shade has on it).