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Sunny and Cloudy day modeling

asked 2017-05-08 01:59:18 -0600

Milad gravatar image

updated 2020-01-20 12:10:16 -0600


I want to consider two different external conditions for my model. One sunny day (direct and diffuse radiation) and another one cloudy day( just diffuse radiation). But I do not know how to do it in Openstudio or EnergyPlus..I would appreciate if you can help me.

Thank you so much.

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answered 2017-05-08 07:25:26 -0600

Dustin gravatar image

You could probably make a modification to a weather file for an individual day if all you are comparing is the models sensitivity to a sunny and cloudy day. The modification would be made to the direct and diffuse radiation values and simply running the file and comparing outputs. This would be the simplest way I can think of immediately.

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Thank you so much for your reply. I am a beginner and I do not know where can I change the direct and diffuse radiation in Openstudio or EnergyPlus. If you can let me know I would be grateful.


Milad gravatar image Milad  ( 2017-05-08 19:21:29 -0600 )edit

answered 2017-05-08 10:54:44 -0600

updated 2017-05-08 11:00:37 -0600

You could just run annual simulation and report back some site variables to find both clear and cloudy days. It would be cool if a report could aggregate "clear, party cloudy, and cloudy" days and present separate results for each day type, but for spot checks looking through results by hand isn't too bad. Would eventually be nice for results apps to have weather bug.

This post has some good information on variables to look at.

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would you please let me know how can I consider clear and cloudy sky in Openstudio or EnergyPlus?

Milad gravatar image Milad  ( 2017-05-08 19:23:05 -0600 )edit

David actually linked to a post in his answer here, which contains some good info on how to determine clear and overcast skies in your specific weather files. The general idea is a) run the annual simulation, b) look at the weather file and pick out some exemplar clear and overcast days (using the information in the post David referenced), and then c) look at your energy use results for those specific days you determined to be clear and overcast.

rpg777 gravatar image rpg777  ( 2017-05-09 11:15:48 -0600 )edit

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Asked: 2017-05-08 01:59:18 -0600

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Last updated: May 08 '17