We are trying to evaluate the best way of meeting this requirement through Option 1 - Simulation according to the latest (May 2011) Addenda changes (min. 10 fc on Sept. 21 at 9 am and 3 pm under clear sky conditions).
We have the project modeled in Sketchup.
My initial thought was to export from Sketchup into Daysim, but I understand there will be a problem with the sensor file and we'll need to create a text file (?). We have Ecotect and can import the .3ds file from the Sketchup Model and then export into Daysim.
I've also learned that Radiance will do the same analysis as Daysim.
Thoughts? What are other design teams using to meet this credit? Thanks in advance.
Ramana Koti
Sustainable Design LeaderHKS, Inc.
12 thumbs up
August 4, 2011 - 1:15 pm
What do you mean by there will be a problem with the sensor file? You can either create a sensor file using a text editor manually based on what you want your sensor coordinates to be or the SketchUp plugin su2ds will automatically create one for you based on the plane and spacing you define. See http://code.google.com/p/su2ds/
I want to say Daysim is your best bet but Sept 21 9am and 3pm may or may not be clear sky conditions (as the credit vaguely requires) depending on the weather conditions in the weather file. Directly in Radiance you can define the sky condition you want. IES-VE might be a good candidate.
Susan M. Kaplan
Director of Specifications and SustainabilityHLW International
70 thumbs up
August 4, 2011 - 1:58 pm
Thanks Ramana. I now have the Sketchup plugin that will allow me to automatically create the text file.
I'll look into Radiance and IES-VE.
Ramana Koti
Sustainable Design LeaderHKS, Inc.
12 thumbs up
August 4, 2011 - 2:50 pm
You're welcome Susan. AGI 32 is another tool that comes to mind.
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
888 thumbs up
August 5, 2011 - 7:03 am
Exporting to Daysim will give you Daylight Autonomy, which is based upon a year's worth of sky data for a location. The requirement is for a specific time and time condition, which Daysim does not create.
I would export your model into Ecotec, and then export to Radiance. Ecotec automatically creates the sensor file which is then used in Radiance and Daysim. You will be able to specify date, time, and sky condition in Radiance. However, your units will be in lux, so you will need to revise the input lux data, which you write a simple formula in the calculation grid import table. This will convert your lux to footcandles. You could also leave it in lux and explain the levels to the reviewer.
Jill Perry, PE
ConsultantJill Perry, LLC
LEEDuser Expert
440 thumbs up
August 5, 2011 - 5:04 pm
Susan, as you can see, daylight modeling is nearly as complicated as energy modeling. Do you hire out for energy modeling? I would recommend the same for daylight modeling. Once you figure out all that is listed here, you still need experience to help you understand the results. Why spend your time and money on training and software when it is a small, specialized portion of your project? Plus, you will develop relationships with these experts who are also experts in glazing and lighting.