[Radiance-general] Using Radiance to Generate Lighting and Solar Surface Heat Gain Schedules for EnergyPlus

[Andrew McNeil]

Justin,

genBSDF "change wavelength tag from visible to NIR":

Since that presentation the tag used by Window has been changed from NIR to
solar, so you should use solar.

Creating Surface Heat Gain Schedule:

We created a pseudo view matrix by tracing rays from the window into the
space and binning rays based on the intersection location and material
modifier. You can use genklemsamp, but have to flip the sign on the z
component of the vector.

Using Schedules in EnergyPlus:
> "EnergyPls code modified to allow schedule of surface heat gains"
> (modification by Thierry Nouidui and Brian Coffey). I was wondering if this
> has be implemented, if so how? I saw in the EnergyPlus EMS manual that the
> EMS system can be used to control exterior building variable, is this the
> same system?

The ability to schedule internal surface heat gains has been incorporated
into the trunk of EnergyPlus starting with version 8.1. The relevant
objects are:

SurfaceProperty:SolarIncidentInside
ComplexFenestrationProperty:SolarAbsorbedLayers

The built in BSDF module gives identical results as using Radiance to
determine solar absorption in the CFS layers.  However using Radiance
offers some improvement in the interior distribution of energy (though it
might not be worth using Radiance for this now that EnergyPlus has built in
BSDF capabilities).

That is the extent of my knowledge of EnergyPlus. I don't want to be
mistaken for someone who knows things about EnergyPlus.

Andy



On Tue, Apr 8, 2014 at 1:47 PM, Lars O. Grobe <grobe at gmx.net> wrote:

> Hi Justin!
>
> > genBSDF "change wavelength tag from visible to NIR":
> > How would one go about running genBSDF for NIR? I read somewhere that
> the material properties should be changed for NIR, but we're not sure how
> to do that. Is there a hidden function that can be added to genBSDF to run
> for NIR?
>
> genBSDF as Radiance offer three channels. Usually we fill those with data
> for three bands in the visible light range and call them RGB. However you
> can assign them NIR if you need to. In this case, make R=G=B=NIR, meaning
> that you need to first define you NIR band and than use reflection /
> transmission measured for this band when setting up you model. Run genBSDF
> and the resulting output will be the BSDF in the NIR-band as you defined
> it. The tag mentioned is in the XML-file, open it with a text editor to
> change it.
>
> Did anyone get a similar approach working with ESP-r?
>
> Cheers, Lars.
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