modeling hourly daylight illuminance/daylight factor values for a year

radiance-general
1

Hi all,

I ask this question with a very basic knowledge of radiance's functioning so
excuse me if the question is not framed well.

Is it possible to program/loop radiance modeling to produce daylight
illuminance or daylight factor values at various points on a work surface of
a space for each hour through the year? (24x365 = 8760 values for a point on
a work plane)

If any, what are the constraints to such a process and how can they be
overcome so as not to model each hour individually?

I am using Radiance on Cygwin.

Thanks in advance,
Ramana.

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--
Venkata Ramana Koti
MS in Building Design (Energy/Climate)
School of Architecture and Landscape Architecture
College of Design
Arizona State University, Tempe AZ 85287

2

Ramana,

A brute-force approach (i.e. a new simulation for every hour) can be done, but it is computationally very inefficient. A better approach is to use daylight coefficients. Background, theory and implementation are described in chapter 6 here:
http://www.iesd.dmu.ac.uk/~jm/zxcv-thesis/
[Web pages seem to be down at the moment - try again later/tomorrow]

An end-user DC version called DAYSIM is available from here:
http://irc.nrc-cnrc.gc.ca/ie/lighting/daylight/daysim_e.html
DAYSIM is different in detail from the description noted above, but does more or less the same thing.

-John

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-----------------------------------------------
Dr. John Mardaljevic
Senior Research Fellow
Institute of Energy and Sustainable Development
De Montfort University
The Gateway
Leicester
LE1 9BH, UK
+44 (0) 116 257 7972
+44 (0) 116 257 7981 (fax)

[email protected]
http://www.iesd.dmu.ac.uk/~jm