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Daylight control only activate in office hour

asked 2021-06-14 13:09:42 -0500

Touispeid gravatar image

updated 2021-06-14 16:01:55 -0500

In InputOutputReference guide, there is " Field: Availability Schedule Name". However, I am not able to find it in the SketchUp plugin. Is it only for E+ not OS? Not sure how we can schedule the daylight control. For example, I only want the daylight control to be activated between 8am-6pm to get desired light level. After office hour, even if the room is dark I don't need the electric light to get that level and it should be kept off. Is there a way to do that? Thanks.

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answered 2021-06-14 14:22:09 -0500

updated 2021-06-14 19:03:44 -0500

It's important to point out that there are two schedules that work together for lighting:

  • The lighting operation schedule input for Lighting objects that determines the fractional use of electricity for lights. This fractional schedule assumes that there are no daylighting controls.
  • The availability schedule input for Daylighting:Controls object that determines when the daylighting controls is available to turn off or reduce the electric lighting, overriding the lighting operation schedule (input parameter above). This is availability -- the daylighting controls won't override normal operation all the time, just if enough daylight illuminance reaches the daylight sensor's position.

So, if you don't need electric lighting after 6pm, that would be reflected in the lighting operation schedule -- schedule values of 0 after 6pm. This can be edited in the Schedules tab (second from the top) in the OpenStudio application.

You can read the OpenStudio Plugin for SketchUp Guide section on adding new daylighting controls for more information. From following this guide in my own testing, the daylighting controls availability schedule input is not exposed in the OpenStudio application or SketchUp plugin. If the space containing a daylight sensor (aka reference point) is assigned to a thermal zone, and the thermal zone has a primary daylight controls, then this is what the EnergyPlus Daylighting:Controls object looks like.

  Thermal Zone 1 DaylightingControls,     !- Name
  Thermal Zone 1,                         !- Zone Name
  ,                                       !- Daylighting Method
  ,                                       !- Availability Schedule Name
  Continuous,                             !- Lighting Control Type
  ,                                       !- Minimum Input Power Fraction for Cont ...
  ,                                       !- Minimum Light Output Fraction for Cont ...
  ,                                       !- Number of Stepped Control Steps
  ,                                       !- Probability Lighting will be Reset When  ... 
  Daylighting Control 1,                  !- Glare Calculation Daylighting Ref ... 
  0,                                      !- Glare Calculation Azimuth Angle of View ...
  ,                                       !- Maximum Allowable Discomfort Glare Index
  ,                                       !- DElight Gridding Resolution {m2}
  Daylighting Control 1,                  !- Daylighting Reference Point Name 1
  1,                                      !- Fraction of Zone Controlled by Reference ...
  500;                                    !- Illuminance Setpoint at Reference Point ...

Note that the availability schedule name input is blank, which default to "always on" (constant value of 1). This is common practice for annual simulations, but design days usually have daylight controls turned off to yield higher heating/cooling capacities and helps avoid unmet heating/cooling hours during annual simulations.

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Thanks Aaron! Your suggestion makes sense to me. However, I can not find availability schedule input in OS or SketchUp Plugin. I don't need it but in case someone else has the same question you might want to provide a bit more detail on where to find it?

Touispeid gravatar image Touispeid  ( 2021-06-14 14:52:08 -0500 )edit

Correct, the daylight controls availability schedule input is not exposed in the OpenStudio application or the SketchUp plugin. I've updated my answer above for more details on this.

Aaron Boranian gravatar image Aaron Boranian  ( 2021-06-14 18:58:07 -0500 )edit

Awesome. Thanks Aaron!

Touispeid gravatar image Touispeid  ( 2021-06-14 19:01:49 -0500 )edit

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Asked: 2021-06-14 13:09:42 -0500

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Last updated: Jun 15