We are using Ecotect analysis 2011 to document credit IEQ 8.1. This program has a natural lighting tool which evaluates the amount of light in fc over a 5ft x 5ft mesh and 30inches above the floor. In this version of Ecotect we can load a climate file and analyze it under a clear sky condition. It is also possible to use radiance software plug-in to render images of the interiors and a Daysim plug-in which apparently gives more accurate results than Ecotect, however we are having problems running it. Does someone know whether the results of Ecotect analysis are sufficient to document this credit successfully?
Thanks!
Paul Rogers
ArchitectBau Arktitekter
3 thumbs up
August 23, 2012 - 2:07 am
Hi Johanna,
I strongly recommend that you use a radiance render engine and NOT the Ecotect built-in motor as Ecotect's built in motor grossly underestimates diffuse radiation. Daysim will do the trick and is very accurate but is rather limited in how much geometry it can receive. There is also a free radiance version which plugs-in nicely and takes sophisticated geometry. The following website gives instructions (http://www.proxyarch.com/wiki/index.php5?title=Radiance_in_Ecotect) . Both add-on software take a bit of a learning curve. Also, I recommend that you use a specialized clear sky climate file and not just the ‘clear sky’ drop down in Ecotect.
TODD REED
Energy Program SpecialistPA DMVA
LEEDuser Expert
890 thumbs up
August 22, 2012 - 8:03 am
Radiance is automatically uploaded when you install Ecotect. So once your model is all set up. Go to calculate, lighting analysis, export to Radiance, select illuminance, select surface and or point analysis, select analysis grid, select sunny sky,current date and time, views that yo have set up, select location for files to be save, final render and ensure generate point data and analysis grid are select.
The one biggest trick is to ensure your file path to where your files will be saved is very short. Otherwise you will get errors. Once the Radiance run is complete just follow the promps.
Daysim is great, but it provides annual simulation results and not point in time calculations which are needed to demonstrate credit compliance. THis is an option in LEED 2012. So for now just use the Radiance plug in for credit documentation.
Eddy Santosa
Director of SustainabilityDBR Engineering Consultants
376 thumbs up
August 22, 2012 - 12:22 pm
Johanna,
As far as I know, Ecotect only runs using uniform and overcast sky. Although you upload the weather file, the ecotect calculation does not use the weather file to do daylight calculation for its overcast and uniform sky. I am not aware if there is any recent Ecotect version that has capability to run clear sky.
There is a good comparison study from Harvard regarding Ecotect and Radiance. The comparison is based on DF (daylight factor) which I believe it should use overcast sky.
In addition to Todd's comment, I will suggest to learn also how to read the radiance file. You may need to tweak the material properties because the translation file from ecotect to radiance is not good.
I second Todd's opinion for Daysim. I heard you can still run less than a year but you may need to adjust the weather file.
Norma Lehman
PrincipalThe Beck Group
133 thumbs up
February 26, 2013 - 4:12 pm
thanks for the clarification