Hello, 

 

I've a problem when running simulations for LEED v4. It works perfectly fine with and without permanent shadings.

But when I use "detailed dynamic shading" the shadings aren't calculated. It’s like they don't exist in the model. When I change the Glazing state "on" and "off" values there is no change. 

 

Any idea what I'm doing wrong? I've no groups and have tried both with complex and simple geometries. 

I've even tried the same settings for the shading in DIVA for rhino 2.0. and there the automatic shading works fine.

Also, I only get the "Daysim Simulation Report" every 10th time..

 

Kind Regards 

Anna

Tags: LEED

Views: 465

Attachments:

Reply to This

Replies to This Discussion

Hi Anna,

Apologies for the late reply. This is a bit of a confusing issue in DIVA. The metric for the LEED v4 calculations (IES-LM-83's sDA / ASE calculations) specifies some very strict dynamic shading control systems, so DIVA will always use those when you run a sDA metric. This is where the little popup asks you to select nodes for each room, and this is completely separate from the detailed dynamic shading in DIVA. The second issue at play here is that the detailed dynamic shading calculations (in Daysim) only allow you to use up to two shading controls, whereas the LM-83 / sDA shading controls allow an unlimited number of rooms for whole-building analysis.

What is explicitly going on is covered in this presentation I gave last year,

LEEDv4 panel discussion [presentation] [mp3 audio]
Kevin van den Wymelenberg, Ed Clark, Eddy Santosa
Moderated by Alstan Jakubiec

Basically, the detailed dynamic shading in DIVA only works with climate-based metrics other than sDA, which is kind of special in DIVA. As per the metric definition, if I recall correctly, automated control systems that will be put into the real building can be used for sDA calculations, but this isn't possible in DIVA right now.

Best,

Alstan

Thank you for the help and all the information. 

I might have to use the option 2 instead. Values between 300 and 3000 lux... etc.

Is it possible to change the "LEED Addendum IEQ 8.1" to fit these values instead of the 10fc - 500fc values?

Kind Regards Anna

 

Hi Anna,

We have an option to load in simulation results for LEEDv4 option 2 from right-clicking on the Metrics button.

The simulations need to be run manually however using the appropriate climate data as per Option 2's requirements. This part has not been implemented into DIVA automatically yet. It will produce a result to run the LEED2009 clear-sky simulations and load them in via this method, but it would not quite meet the simulation requirements of v4 Option 2.

Best,
Alstan

Hello again, 

 

I apologize for all my questions.

I've been trying to do the sky settings manually. Using this discussion as a tutorial to find the values for "direct normal irradiance" and "diffuse horizontal irradiance". 

(http://diva4rhino.com/forum/topics/leed-v4-credit-7-daylight-option-2-point-in-time)

 

I'm a bit surprised that the morning is brighter than the afternoon. Is the data output correct? Can I use these values?

(the weather data file is from Copenhagen) Or which sky should I use instead? Clear Sky with Sun (CIE Clear Sky)?

 

Kind Regards Anna

Update

I received help from an expert on LEED.

"Hi Anna, 
I checked through the Grasshopper definition that you used. I tried it out with the weather data from Copenhaguen and I got the same results as you. 
The way that definition works is: 
* It finds out what is the lower level of SkyCover from the weather data for the given dates.

* It finds out how many of the 62 days checked (considering spring and autumn together) have that minimum level of skycover.

* It averages the direct horizontal radiation and the direct normal radiation for all these dates.

According to the Option 2 in LEED you should pick one day in spring and one day in autumn (the most favorable) and then average these two values for 9.00 and 15.00, which as I said is not exactly what the definition you used does. I modified the definition to adapt it to this and I got the following results:

kl 9: DNI: 657.0 Wh/m2 DHI: 112.5 Wh/m2 
kl 15: DNI: 574.5 Wh/m2 DHI: 104.5 Wh/m2"

Hi Anna,

Thanks for the update. I am glad that you got some favorable results. I find the LEEDv4 Option 2 inputs a little weird, but probably better than what happened in the previous version of LEED.

Best,

Alstan

Hi Anna,

I made the original definition and I found this topic by a coincidence. Thanks for correcting this. Next time, I'd love a comment in the original thread also to correct it ;-).

Any chance you can upload your corrected gh definition?

Anna Nilson said:

Update

I received help from an expert on LEED.

"Hi Anna, 
I checked through the Grasshopper definition that you used. I tried it out with the weather data from Copenhaguen and I got the same results as you. 
The way that definition works is: 
* It finds out what is the lower level of SkyCover from the weather data for the given dates.

* It finds out how many of the 62 days checked (considering spring and autumn together) have that minimum level of skycover.

* It averages the direct horizontal radiation and the direct normal radiation for all these dates.

According to the Option 2 in LEED you should pick one day in spring and one day in autumn (the most favorable) and then average these two values for 9.00 and 15.00, which as I said is not exactly what the definition you used does. I modified the definition to adapt it to this and I got the following results:

kl 9: DNI: 657.0 Wh/m2 DHI: 112.5 Wh/m2 
kl 15: DNI: 574.5 Wh/m2 DHI: 104.5 Wh/m2"

Reply to Discussion

RSS

© 2017   Created by jeff niemasz.   Powered by

Badges  |  Report an Issue  |  Terms of Service