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# Is it possible to obtain annual glare maps using Open Studio?

Hi guys

I'm coming here to ask about the output of glare simulations using Open Studio/Energy Plus. It is possible to obtain an annual calcuation, sort of an annual glare map of glare?

I have some problems to run simulations using the latest version of Open Studio & Energy Plus with the computer that I'm using now, so I cannot really test this now. I hope that somebody can give me a hint while I fix this problem. I thank you in advance Steph

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Yes, OpenStudio has Glare Sensor objects you can place in your model, which will calculate vertical illuminance as well as Daylight Glare Probability Simplified (DGPs), which is based on vertical eye illuminance. The DGPs is calculated for every glare sensor view, for every hour, and is saved to the space's daylighting results directory. Results are stored in the format: (month),(day),(time),(DGPs), e.g.:

1,1,08:00:00,0.1855886095523

1,1,09:00:00,0.18451802954957

1,1,10:00:00,0.2000663350443

1,1,11:00:00,0.20581065771419998

1,1,12:00:00,0.1969010569402

1,1,13:00:00,0.1863662052781

If you had multiple glare sensors in the space (or multiple views per glare sensor), you'd just have a longer array of DGPs values following the mon/day/hr bits. You could take this data and plot it for an annual overview. There are some caveats:

• A big missing tooth in the dataset is the spatial (coordinate) data
• DGP-simplified is technically only reliable for views where there is no direct sun, since the spatial/positional aspect of the flux is lost to the integral (illuminance)

We hope to resolve these issues for v1.8.0 as Larry states above. We will offer true DGP reporting (based on a simple image -- good enough to resolve position indices), and include spatial data with it, allowing for far more robust reporting, as well as allowing for glare to be used as a control signal.

P.S. @TaylorRoberts, the illuminance maps are intended for computing the spatial distribution of the daylight flux, hence the name. This is not the same thing as glare, tho technically you can get useful daylight illuminance (UDI) from these maps, and UDI canserve as a proxy for glare. See this paper for some great info on this, and -- as always -- some more caveats: http://infoscience.epfl.ch/record/179939

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May I ask two more questions, 1) Annual glare can be then calculated using glazing systems (xml files) obtained from Window 7? 2) is it possible to know since when this feature (annual glare calculation) is available in Open Studio? Meaning the year or the version of the software? I would like to include this information in my report.

Sth

( 2015-02-05 09:17:15 -0500 )edit
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Support for BSDFs from the Window program is in the work plan, but probably won't be added until September for OpenStudio 1.9.0. That said, relying on BSDFs (the XML files from Window or even from physical measurement) for glare evaluation is a wiggly proposition, because the standard Klems basis for hemispherical subdivision is only 145 patches. This will take any really "spiky bits" (i.e. high flux concentrated in a small solid angle) and spread the flux across one of the larger Klems solid angles, potentially missing some glare.

( 2015-02-05 15:32:23 -0500 )edit

Thank you so much for your time and help...! :) Steph

( 2015-02-06 17:54:14 -0500 )edit

Glare metrics should be coming in a future release of OpenStudio - I'm guessing 1.8.0 in June, but I'll defer to Rob G. for the official answer.

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OpenStudio has the ability to create "illuminance maps" in the SketchUp plugin which should give you what you are looking for.

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