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E+ EMS based on timesteps

asked 2016-02-05 19:17:04 -0600

Alex Vlachokostas's avatar

updated 2016-10-21 12:29:52 -0600

Hi everyone,

  • The fact:

I have simulated 25 different light-redirecting glazings (BSDFs) in Radiance. After post-processing the results I know for a specific time of the day which light-redirecting glazing is the best in terms of good illuminance levels and minimum glare for the occupant. Essentially, I have a file with 2 columns. Column 1 has the hourly timestep for a year (rows: 1 to 8760) and column 2 has the name code of the optimal light-redirecting glazing (e.g., Window_i) in terms of illuminance and glare for each timestep.

  • The question:

Which variable do I use in E+ EMS in order to call a different WindowMaterial:Glazing object for every timestep of the E+ simulation? For example, in a 'high-level' way it might look like a 8760 times loop that would read each line of the aforementioned column 2:

IF timestep = 8, SET WindowMaterial:Glazing, Window_1, ENDIF;

Thank you.

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How did you obtain the BSDFs for the different glazings? I have found this to be a problem. The manufacturers I have contacted haven't been able to provide the BSDF information.

Chris Jones's avatar Chris Jones  ( 2016-02-08 08:15:36 -0600 )edit

You can obtain the BSDF in WINDOW (software from LBNL- link text). You can put together layers of different glass typologies that are available in the software's database and then you calculate the BSDF XML file that you can use at your E+ simulations. This is how you do it: Ref: link text (focus on the "Generating BSDF XML" files).

You can do the same in Radiance (Ref: link text) but, in my opinion, the degree of difficulty is much higher.

Alex Vlachokostas's avatar Alex Vlachokostas  ( 2016-02-08 10:02:58 -0600 )edit

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answered 2016-02-05 22:28:31 -0600

Chandan Sharma's avatar

EMSThermochromicWindow.idf provides a good starting point here. EMS program should determine hour of simulation (1-8760) using the built-in variables (DayOfYear and CurrentTime/Hour may be particularly useful), and appropriate window construction should be chosen.

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Asked: 2016-02-05 19:17:04 -0600

Seen: 281 times

Last updated: Feb 05 '16