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# How to model different types of shadings in OpenStudio and EnergyPlus

I have built my model in OpenStudio and tried to model different shading scenarios in OpenStudio and afterwards in EnergyPlus but couldn't.

I used WindowProperty:ShadingControl in EnergyPlus and the only type of shading which worked was SwitchableGlazing but When I try with other types such as Interior or Exterior shade or blind it fails.

I have already defined Shading and blind material and added it to construction of the window, but faces the error:

GetHTSubSurfaceData: Window "SUB SURFACE 2" must not directly reference a Construction (i.e, "WINDOWS USED") with a shading device.


In FenestrationSurface:Detailed I have tried both referring and not referring to the defined shading control, but always face the above error.

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Without seeing the portion of your idf file with the shading and window constructions, it will be harder to help. From looking at the InputOutputReference document with v8.0 of E+, on page 109 after describing two possible methods to include shading effects, it says:

"You will get an error message if you try to reference a shaded construction directly from FenestrationSurface:Detailed."

Sounds like this is what is happening in your case. The InputOutput Reference also begins to explain the WindowProperty:ShadingControl on page 234 for v8.0, with an example that starts on page 241. It defines a WindowMaterial:Glazing for the UNSHADED window (GLASS - CLEAR SHEET 1/8 IN), and a WindowMaterial:Shade for the shading material (ROLL SHADE). It then defines TWO constructions, one of the unshaded window and one of the window with the shading material.

Construction,
GLASS - CLEAR SHEET 1 / 8 IN; !- First material layer

Construction,
GLASS - CLEAR SHEET 1 / 8 IN, !- First material layer
ROLL SHADE ; !- Second material layer


The example then defines a WindowProperty:ShadingControl object (CONTROL ON INCIDENT SOLAR) and references the construction WITH the shading material.

WindowProperty:ShadingControl,
CONTROL ON INCIDENT SOLAR, !- Name of Shading Control
SINGLE PANE WITH INT SHADE, !- Name of construction with shading device
, !- Schedule name
50.0, !- Setpoint {W/m2}
NO, !- Shading Control Is Scheduled
NO, !- Glare Control Is Active
, !- Material Name of Shading Device
, !- Type of Slat Angle Control for Blinds
; !- Slat Angle Schedule Name


The example ends by defining the window with a FenestrationSurface:Detailed object for the model's window where shading is implemented (Zn001:Wall001:Win001 in the example, looks like Sub Surface 2 for your model). This object uses the window construction WITHOUT shading, and then uses the ShadingControl object defined earlier.

FenestrationSurface:Detailed,
Zn001:Wall001:Win001, !- SubSurface Name
Window , !- Class
SINGLE PANE WITH NO SHADE, !- Name of construction without shading device
Zn001:Wall001 , !- Base Surface Name
, !- Target
0.5000000 , !- VF to Ground
CONTROL ON INCIDENT SOLAR, !- Window Shading Control name
, !- Frame/Divider name
1.0 , !- Multiplier
4 , !- Number of vertices (assumed rectangular)
0.548 , 0.0 , 2.5 , !- x,y,z of vertices {m}
0.548 , 0.0 , 0.5 ,
5.548 , 0.0 , 0.5 ,
5.548 , 0.0 , 2.5 ;


Hope this helps. There is a second example that follows a very similar process, but instead of creating two window constructions, you create only the unshaded window construction and enter the shading material name as the ", !- Material Name of Shading Device" input for the "WindowProperty:ShadingControl" object.

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UPDATE: After looking into why your model did run for SwitchableGlazing, I found this statement under the WindowProperty:ShadingControl info in the InputOutputReference:

"Specifying “Name of Construction with Shading” is required if Shading Type = BetweenGlassShade, BetweenGlassBlind, or SwitchableGlazing. For other Shading Types, you may alternatively specify “Material Name of Shading Device” (see below)."

So, SwitchableGlazing might have been the only shading type you tried that would work by entering a shaded (or dimmed in this case) window construction.

( 2014-10-30 13:10:32 -0500 )edit

Thanks a lot Aaron for your detailed explanation! it was amazing!! In fact your comment helped me to solve the problem. I defined the Window construction without shading (WindowMaterial:Glazing) and also defined WindowMaterial:Shade. and for WindowProperty:ShadingControl, I used different types of shading, referred "Shading device material name", but left the "Construction with shading name" blank and it works perfectly. Thanks again!!

( 2014-10-31 12:24:06 -0500 )edit

You're welcome! I had never tried to use that component, so it was good to do research myself and understand how it works. If you like the answer I gave, go ahead and click on the "check" button so that your question is marked as answered on Unmet Hours.

( 2014-10-31 12:53:39 -0500 )edit

I wrote a basic tutorial on using shading controls in OpenStudio here. I can update this if it is missing any information.

HTH, Dan

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