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

How to model two-axis dynamic shading?

asked 2016-01-14 09:39:22 -0600

jarno55 gravatar image

updated 2016-01-14 13:52:14 -0600


I am currently working on a project with a dynamic facade and i want to use thermal simulations to evaluate the optimal states of said facade depending on temperature and solar radiation.

So far i've been working with energyplus through grasshopper and DIVA/Viper for my calculations, but i've only done simulations for static states of the facade.

Now i want to change to a dynamic modeling of the facade, so for example a fixed schedule where i change the geometry used for the shading calculations every 15 minutes or every hour. After reading through the energyplus documentation, i have the feeling, that it's not possible. The only dynamics allowed appear to be being able to change the horizontal angle OR the vertical angle of slats. However, our facade has elements, that can change both horizontal and vertical angles.

Is there a possibility to change the shading geometry during the simulation with energyplus to any state i'd like? Or if not, is there another program, that might be able to do that? If all else fails, how difficult do you think it is to change the source-code of energyplus, to add this feature?

Thanks a lot in advance for any advice!

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2016-01-14 10:36:24 -0600

EnergyPlus does not have the capability to change surface orientation dynamically.

Part of the challenge in implementing this in the EnergyPlus source code, is that EnergyPlus performs shading calculations periodically throughout the year. That is, each surface is given a daily shading profile based on the suns position for each timestep on a specific day. You can have this update every day of the year, but it will drastically increase the simulation time.

If you were to add this capability to the EnergyPlus source, it would probably be best to approach it similar to the window blind model, where the actual surfaces are not defined as part of the geometry, but as a modifier on the transmitted and reflected solar energy incident on the window.

How difficult is this to do depends on your familiarity with C++ and your patience in learning the EnergyPlus source structure.

edit flag offensive delete link more


Thank you for your answer!

I guess i will first wait now, as maybe someone knows an alternative to energyplus. I heared that trnsys is a similar simulation engine, though i do not know much about it, so maybe i have to start looking into it. Are there any further building simulation tools, that i don't know of?

jarno55 gravatar imagejarno55 ( 2016-01-15 04:52:40 -0600 )edit

Your Answer

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

Add Answer


Question Tools

1 follower


Asked: 2016-01-14 09:39:22 -0600

Seen: 129 times

Last updated: Jan 14 '16