[esp-r] FW: Multiskin facade and daylight study

[Jon Hand]

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From: Jon Hand
Sent: 02 February 2009 15:33
To: perhaugaard at yahoo.dk
Subject: RE: [esp-r]  Multiskin facade and daylight study

A couple of questions about radiance for daylight studies....
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In a current project I need to make a daylight study in building with a multiskin facade. Focus is on daylight factors and energy delivered from the sun. I am modeling this as a two zone model.

Problem:
I need to investigate how tilting the exterior facade effects the daylight factors and energy delivered from the sun.

Question:
1) Can ESP-r/Radiance take sun penetrating from an adjacent zone into account and how is the partition modeled?

2) I guess if ESP-r/Radiance can handle question 1 the package can also calculate daylight factors and energy delivered from the sun from a tilted facade :)

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Yes, esp-r deals with sunlight passing between zones - this is treated as a diffuse source
as it goes from one zone to the adjacent zone.  You can have a mix of opaque and
transparent surfaces which form partitions between zones.  Typically partitions
are symmetrical and thus the optical properties are the same for the partition
in both of the zones.

Sloped facades are probably not a problem - and be sure that the edge
ordering begins along the bottom edge and goes anti-clockwise.  Make sure
that surfaces are actually flat.

And if you export and esp-r model to Radiance then radiance will work as normal for
portions of a building which are connected by mixtures of opaque and transparent
surfaces.  If you ask for daylight factors then usually it does not matter how many
zones there are or how many transparent partitions there are - it will eventually
finish computing and show you the grid of daylight factors.

To explore this find one of the exemplar models which has a glass partition
and pass it to Radiance and see what happens.

-Jon