What I just did on a project was to run the building model in Daysim
to determine the light level in lux achieved in each space and generate an 8760
report.
Then I determined what fraction of light as compared to the
design light level I would achieve through daylighting.
The power fraction reduction is [1-(sensor lux/design lux)].
Then I have a artificial lighting schedule for my building
within the Studio that I multiply the schedule fraction by the daylight
fraction to get the actual artificial light fraction for that hour.
Something you should be aware of is the limitations of your ballasts.
If the ballasts are stepped or can only dim to 50%, you will need to add more
logic to properly represent your lighting control system.
Also, make sure if you are controlling your blinds in radiance
to reduce glare that you use the same algorithms in TRNSYS because of the solar
heat gain on the windows.
Let me know if you have any questions.
Fred
|
Fred Betz PhD.,
LEED AP
Sustainable Systems Analyst
|
|
AEI |
AFFILIATED ENGINEERS, INC.
5802 Research Park Blvd. | Madison, WI 53719
P: 608.236.1175 | F: 608.238.2614
fbetz@aeieng.com | www.aeieng.com
|
From: Matt Duffy
[mailto:duffy@tess-inc.com]
Sent: Friday, September 17, 2010 11:28 AM
To: Kent Beason; trnsys-users@engr.wisc.edu
Subject: Re: [TRNSYS-users] Radiance to/from TRNSYS
Hello Kent,
I actually was just presented a response by another user, Cramer Silkworth. I
am unfortunately not too familiar with Radiance, but here was the response.
Best regards,
Matt Duffy
"Both trnsys and radiance are very powerful
simulation engines. Though graphical interfaces for both exist (built-in with
Trnsys, in Simulation Studio, and as add-ons for Ecotect and Sketchup for
Radiance), they are most powerful when used like a programming language - ie,
modifying their text input files directly. This gives you the most control, and
once you learn their syntax, I'd say easier than the graphical interfaces.
Especially for parametric studies.
If I were to want to couple radiance and trnsys for a project, I'd be using
DaySim as a front-end for radiance. Version 3 is on the verge of final release
(workable beta is available now - www.daysim.com),
and it's free. It essentially runs radiance for your geometry in an annual
simulation (with weather data), can handle active shading and electric
lighting, and has numerous outputs - including one intended for coupling to
trnsys. Then you just need to set up your trnsys model to read this file from
daysim (it comes with a generic data file reader component), and then you use
your results to modify your lighting power accordingly (or whatever variable
you want to respond to lighting conditions). I can't say I've used too many
other daylight & energy modeling programs, but I'm fairly confident there
are very few if any other programs out there that can handle such a coupling as
detailed as trnsys & daysim/radiance can. I've heard of it being done with
eQuest, but I think the eQuest side of things is a bit limited. There are other
daylight simulation programs as well, but Radiance is always talked of as being
the industry 'standard.'"
----- Original Message
-----
From: "Kent Beason"
<kbeason@schlitterbahn.com>
Sent: Fri, September 17, 2010 10:24
Subject: [TRNSYS-users] Radiance to/from TRNSYS
Dear TRNSYS users,
I am on the Radiance users
list and the following question regarding TRNSYS was posted in that
group. I believe they want to control the window blinds & the zone’s
artificial lighting based on lumens entering the zone:
We want to simulate the
lighting conditions in a building with the RADIANCE Software.
The Simulation depends on
the natural and artificial light and the window blinds.
After this simulation, we
want to send the results from RADIANCE to a simulation software called TRNSYS.
Here are my questions
regarding this topic:
Is it possible to couple RADIANCE with TRNSYS?
Does RADIANCE only image-files (as output) produce?
Have anybody of you, connect TRNSYS with RADIANCE successfully?
And have you any tutorials or other useful documents/links?
Thank you in advance.
Regards,
Marion
Kent Beason
Schlitterbahn
Development Group
830-609-8904 m
830-608-8040 f
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