[Radiance-general] Help - Radiance / LEED

[Guglielmetti, Robert]

Hi Ignacio,

You can indeed calculate the values you need for the LEED daylight credit documentation with Radiance. To be clear, Radiance by default calculates, well, radiance, in w/sr/m^2. This can be converted to luminance (cd/m^2). Now, to get the info you need for LEED, you need to tell Radiance to calculate irradiance instead of radiance, and convert that to lux or footcandles as needed. To do this you would specify the –I (capitol i) option to rtrace, which is the Radiance tool you'd use to calculate values for a grid of points, and then multiply the rgb irradiance values by V lambda. There are plenty of examples in the list archives of little scripts and commands to send Radiance a grid of points and do these calculations and make the proper conversions to the photometric values.


Rob Guglielmetti  IESNA, LEED AP
Commercial Buildings Research Group
National Renewable Energy Laboratory
1617 Cole Blvd MS:RSF202
Golden, CO 80401
T. 303.275.4319
F. 303.630.2055
E. robert.guglielmetti at nrel.gov


From: Ignacio Fajardo <primiark at gmail.com<mailto:primiark at gmail.com>>
Reply-To: Radiance general discussion <radiance-general at radiance-online.org<mailto:radiance-general at radiance-online.org>>
Date: Wed, 13 Apr 2011 09:12:59 -0600
To: "radiance-general at radiance-online.org<mailto:radiance-general at radiance-online.org>" <radiance-general at radiance-online.org<mailto:radiance-general at radiance-online.org>>
Subject: [Radiance-general] Help - Radiance / LEED

Hi everyone

I need feedback or help to calculate daylight for LEED using Radiance.
Have anyone here acomplished this calculations before? I know  that I have to use footcandles for LEED and radiance use cd/m2. I have to convert each grid point and the scale to footcandle?

Best regards

--
        Jorge Ignacio Fajardo F-A
                   Arquitecto MDCS

iBSA - Ingeniería Blanda S.A
USGBC Member
Jean Mermoz 12, of. D
Of.: (562) 934.7083
Cel. (567) 8782497

Las Condes, Santiago. Chile