Hello, 

I have a question about running thermal analysis in case of a complex shading device defined in Grasshopper. 

Since Energy Plus is working only with planar surfaces (as far as I know, please correct me if I am wrong) I was wondering if there is a way to 'simplify' the process by entering some 'coefficients' in IDF file?

The paper on this link: http://www.gsd.harvard.edu/research/gsdsquare/Publications/Omidfar-...

is about how to run it in Design Builder, but to be honest, I have never used it...

''In order to model the effect of the Ornamental Hybrid Screen on the energy consumption of the space, specific performance criteria of the Screen had to be measured using DIVA, including the screen's shading coefficient and a yearly electric lighting schedule based on DA. The results were then synchronized with a thermal analysis performed in Design Builder linked with Energy Plus (Reinhart, 2010).''

Basically, I should introduce the shading coefficient in IDF Energy + file? Or I am wrong? And also, how can I calculate it? 

Regarding the lighting schedule, I know it should be defined in IDF file and I know how to do it manually, but how can I define one that is based on DA?

I hope you do not find my questions confusing, I do not have too much experience in this software, but I am willing to learn it!

Thanks everyone for help!

Danijel

 

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sorry can you elaborate more  

explain a little the process for doing it   

I understand that those are the X,Y,Z but the geometry it self is for a triangle (right?) can we change it ? 

and how to apply the shading schedule and in which format? (csv with 8760 hours?)

Shading:Building:Detailed,
        Shading Screen Object, !- Detached Shading
        ShadingTransmittance Schedule, !- Shadowing Transmittance & Schedule
        3, !-Triangle
        33.52800 , 10.66800 , 10.05800 ,
        33.52800 , 13.71600 , 0.9140000 ,
        33.52800 , 4.572000 , 0.9140000 ;

 

 

Thank you,

Yes, you can make it a 4 point object by changing the '3' above to a '4' and then adding another coordinate. Another way to do it is to add a shading surface in DIVA and then change its transmittance schedule manually.

Usually I link the transmittance schedule as a csv file that looks something like this,

Schedule:File,
 Transmittance Schedule, !- Name
Fraction, !- Schedule Type Limits Name
 C:\DIVA\temp\z1_B-dflt-glazing\sched.csv, !- File Name
5, !- Column Number
4, !- Rows To Skip
8760, !- Hours of Data
Comma; !- Column Separator

Alstan

Hi Alstan

I analyzed an adaptable facade that is not modeled in grasshopper.after daylight and  electric lighting analysis , I changed the model into a thermal model and analyzed it thermally, I should say that the screen is consisted of 4 sided surfaces(planar surfaces),

but now I wonder if it is correct or not?should I do the process mentioned above or it is just done in case of complex models?

Hi Mona,

Because the surfaces Azadeh used were curved and highly complex, EnergyPlus was not capable of resolving them well. Also, she wanted to account for reflections as light passes through the facade, which I would not trust EnergyPlus to do well. 

I think its OK to use EnergyPlus with the above in mind for most simpler cases, especially when you are doing the lighting calculations in a software like DIVA/Radiance/Daysim.

Best,

Alstan

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