Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question
2

Sunny and Cloudy day modeling

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

Milad's avatar

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

Hello,

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.

edit retag flag offensive close merge delete

2 Answers

Sort by ยป oldest newest most voted
3

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

Dustin's avatar

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.

edit flag offensive delete link more

Comments

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.

Thanks

Milad's avatar Milad  ( 2017-05-08 19:21:29 -0600 )edit
2

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.

edit flag offensive delete link more

Comments

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

Milad's avatar 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's avatar rpg777  ( 2017-05-09 11:15:48 -0600 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Training Workshops

Careers

Question Tools

1 follower

Stats

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

Seen: 263 times

Last updated: May 08 '17