Is it possible to use EMS to change the construction of the shade?

asked 2021-03-02 17:07:37 -0600

uuiiek
83 ●3

Hi there,

I am wondering if it is possible o use EMS to alter the shade construction?

I can define a window with shade construction in the window control object, but it appears that I am unable to modify this construction by EMS once it is set.

I was thinking about instead of window shade control, I just assign the construction with shade to the window surface and then use EMS to dynamically change window construction. However, this failed also because "Window must not directly reference a Construction with a shading device. Use WindowShadingControl to specify a shading device for a window."

I am quite stuck here because I cannot think other alternatives.

Does anyone know how to get around this? If not, any anyone know what are the equivalent solutions?

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answered 2021-03-03 10:33:08 -0600

shorowit

11931 ●203 ●9 https://www.nrel.gov/b...

updated 2021-03-03 11:13:15 -0600

As of E+ 9.4, a window may reference multiple WindowShadingControls/Shades. You can then set each WindowShadingControl's shading control type to OnIfScheduleAllows and define schedules across the multiple WindowShadingControls such that only one shade is active for a given period. If you don't know the schedule in advance, you can use an EMS program to actuate the schedules.

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gotcha. I am wondering if you have any exmaples?

uuiiek ( 2021-03-03 10:38:27 -0600 )edit

Here is an example IDF that uses different Shade objects for summer vs winter for all windows.

shorowit ( 2021-03-03 11:01:22 -0600 )edit

I see. thank you for the help and I'll give it a try later today...

thank you very much.

uuiiek ( 2021-03-03 11:11:42 -0600 )edit

so if I understand correctly, before 9.4, one window can only have one shade control object. After 9.4, one window can be referenced by multiple window objects. Is this correct?

uuiiek ( 2021-03-03 11:15:14 -0600 )edit

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answered 2021-03-03 08:20:37 -0600

rafael.alonso
933 ●1 ●6 ●12 http://atmoslab.io

You could calculate your window+shading properties using LBNL window or following EN ISO 52022-3:2017, and input them as a WindowMaterial:SimpleGlazingSystem. Depending on what you are after, this could be accurate enough as far as I know.

Then, you can use the EMS to switch between the construction assigned to your window with the EnergyManagementSystem:ConstructionIndexVariable.

Rafael