Hello,

I am a lighting design student familiar with Daysim/DIVA/Radiance.  My question is, how can I accurately create a Kalwall like material for DIVA simulations? I know it is Radiance based and changing the text file should do it, but can an experienced user direct me to the correct values to simulate the diffusivity and translucency of the wall system?

http://kalwall.com/aerogel.htm

Furthermore, when creating an energy model of the floor plan (with the perimeter Kalwall wall system), should I perform the simulation in Viper with Grasshopper, EcoTect, EnergyPlus, or can I directly use DIVA to estimate cooling loads?  Likewise, I need to simulate the resistance value of Kalwall (R-20)?  This is the part where I am a bit confused.

Thanks for the help in advance!

Reinhardt

Penn State

Tags: daylight, diva, ecotect, grasshopper, kawall, material, properties, radiance, resistance

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Sorry to add, but I do see the new version of DIVA does have single zone thermal calcs.  If the area of interest is part of a larger floor plan, how is the best way to separate the interest area from the rest of building (concerning material thermal properties)?

Bests,

Reinhardt

Hi Reinhardt,

The material 'GenericTranslucentPanel_20' is actually based on a Kalwall panel. See the paper, 

Reinhart C F, Andersen M, "Development and validation of a Radiance model for a translucent panel", Energy and Buildings 38:7 pp. 890-904, 2006

If you are interested in learning more. 

If the area of interest is part of a larger floor plan, how is the best way to separate the interest area from the rest of building (concerning material thermal properties)?

One possibility is to use adiabatic walls for separations between internal portions of the building. You will probably need to make an EnergyPlus material to account for the thermal properties of the Kallwall R-20 (US) panel.

Best,

Alstan

Alstan,

Thanks for the reply.  The paper you posted is perfect.  Could someone direct to me making an EnergyPlus material?

In that regard, I can just Diva Thermal calculations correct?  If so, that'd be great.

Thanks,

R

Hi Reinhardt,

I actually did this for the presentation of DIVA-2.0 back in 2011 (see the presentation). The material I used for that is something like the below,

WindowMaterial:Glazing, glazed_element, !- Kalwall 
SpectralAverage, !- Optical data type {SpectralAverage or Spectral}
, !- Name of spectral data set when Optical Data Type = Spectral
0.1, !- Thickness {m}
.2, !- Solar transmittance at normal incidence
.1, !- Solar reflectance at normal incidence: front side
.1, !- Solar reflectance at normal incidence: back side
.2, !- Visible transmittance at normal incidence
.15, !- Visible reflectance at normal incidence: front side
.15, !- Visible reflectance at normal incidence: back side
.0, !- IR transmittance at normal incidence
.84, !- IR emissivity: front side
.84, !- IR emissivity: back side
0.0284, !- Conductivity {W/m-K}
1; !- Dirt Correction Factor for Solar and Visible Transmittance

Which should give a US R-Value of 20, though do check my numbers. It then gets applied to an EnergyPlus construction like so, 

Construction,
kalwall, !- Name

glazed_element; !- Material

These go into your c:\DIVA\Thermal\Rhino\04_material_construction.idf file.

Best,

Alstan

Alstan,

Much thanks for the help.  This is great knowledge!

Regards,

R

Alstan,

I am making the Kalwall material and folloed the directory to C:\Radiance\bin where I found a KalwallTranslucent15nano.dat file (this is the exact product I am using).  So I am editing the material file as below by copy pasting from the generictranslucent data:

# material name: GenericTranslucentPanel_20PercentTransmittance
# material color: 175,200,200
# material type: translucent panel
# author: Christoph Reinhart
# comment: This is a validated Radiance model of a translucent sandwiched panel with a
#      direct normal transmittance of ~20%.
#     The Radiance model is based on goniophotometer measurements take at Ecole
#    Polytechnique Federale de Lausanne and integrating sphere measurements taken at
#    the Fraunhofer Institute for Solar Energy Systems, A description of the underlying
#    model was published under in:
#    Reinhart C F, Andersen M, "Development and validation of a Radiance model for a
#    translucent panel", Energy and Buildings 38:7 pp. 890-904, 2006
#
#     The model requires the following two files have been added to a directory included in your
#    RAYPATH variable (c:\daysim\lib or C:\Radiance\lib):
#    rang.cal & Translucent20.dat
#  
void transdata GenericTranslucentPanel_20
4 noop GenericTranslucent20.dat rang.cal rang
0
6 0.40446 0.40446 0.40446 0.08 0.435635 1

void transdata Kalwall
4 noop KalwallTranslucent15nano.dat rang.cal rang
0
6 0.40446 0.40446 0.40446 0.08 0.435635 1

Besides changing the text after the "noop" command, how do I determined the 6 values in the bottom row?  Is the similar way that regular trans materials are formed?

Thanks in advance for the help.

R.

Hi Reinhardt,

 

Its all black magic to me, but this material definition comes with some helpful information (only in the official Daysim installer), pasted below.

 

 


# material name: KalwallTranslucent15nano
# material type: translucent panel
# manufacturer: Kawall Inc, NH, USA
# author: Christoph Reinhart
# date: October 2006
# comment: This is a validated Radiance model of a translucent sandwiched panel with a
# direct normal transmittance of ~15%.
# The Radiance model is based on integrating sphere measurements taken at
# the Fraunhofer Institute for Solar Energy Systems. A description of the underlying
# model can be found under:
# Reinhart C F, Andersen M, "Development and validation of a Radiance model for a
# translucent panel", Energy and Buildings 38:7 pp. 890-904, 2006
#
# The model requires that the following two files are being added to a directory included
# in your RAYPATH variable, e.g.: C:\Radiance\lib or C:\Daysim\lib
# rang.cal & KalwallTranslucent15nano.dat
#

# RADIANCE 'transdata' model of a translucent panel assuming
# Rd = Cr = Cg = Cb = 0.21 (diffuse reflectance)
# Rs = A4 = 0.08 (specular reflectance)
# Sr = surface roughness = 0
# Td = direct direct hemispherical transmittance = 0.1440
# Ts = transmitted specularity (ideal diffuser) = 0
# A6 = (Td+Ts)/(Rd+Td+Ts) = 0.5333 = 0.406746028
# A1 = A2 =A3 = Rd/((1-Rs)*(1-A6)) = 0.384760794
# St = A6*A7*(1-A1)*A4 = 0

void transdata KalwallTranslucent15nano
4 noop KalwallTranslucent15nano.dat rang.cal rang
0
6 0.384760794 0.384760794 0.384760794 0.08 0.406746028 1
# A1 A2 A3 A4 A6 1

Alstan,

Black magic is right.  Thank you for your help on this.

Bests,

R.

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