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Why my EMS cannot change the daylighting illuminance output variable?

asked 2018-06-25 07:02:00 -0500

EastDragon gravatar image

updated 2018-06-29 07:06:07 -0500

I'm trying to use the EMS to switch the visible transmittance(Tv) of EC windows automatically.However, the Tv has been changed,the output variable:Daylighting reference point Illumilance hasn't been any change,just is the same as as the primary.That is to say,the EMS just has changed the Tv of windows but anything.

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If you posted a link to your IDF or inserted the text lines of your EMS objects, people would likely be able to provide more help.

Aaron Boranian gravatar imageAaron Boranian ( 2018-06-29 10:59:22 -0500 )edit

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answered 2018-06-29 11:01:09 -0500

To modify window properties with EMS, you need the following:

  1. EnergyManagementSystem:Actuator for Surface, Construction State
  2. EnergyManagementSystem:ConstructionIndexVariable objects to determine the index for each construction that will be used.
  3. EnergyManagementSystem:Program to assign the desired construction state.
  4. ShadowCalculation, TimestepFrequency;object.

Example file EMSThermochromicWindow.idf illustrates the use of the construction state actuator. If you add daylighting controls to this, there will be little impact, because the south zone has six or so windows and the EMS is only acting on one of them. Deleting the other windows shows that illuminance tracks the changes in window construction state, but they are lagged by one zone timestep. Reference issue #4266

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Asked: 2018-06-25 07:02:00 -0500

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Last updated: Jun 29 '18