[TRNSYS-users] Artificial lighting

David BRADLEY d.bradley at tess-inc.com
Wed Mar 26 09:58:10 PDT 2014

   As with most things in TRNSYS, there is not just one way to do 
lighting. The most important thing to keep in mind about it is that 
TRNSYS does not do any kind of day or artificial light level analysis in 
the building model. It is only taking into account the heat gains that 
are associated with the lighting. Type15 (the weather data reader) does 
give you a value of the outdoor luminous intensity but you'll notice 
that this value is directly tied to its calculation of solar radiation.

   If you make your building using the wizard then a default on/off 
lighting controller with deadbands is added to the project. The 
controller is set up so that if the lights are ON they will stay ON 
until the amount of solar radiation on the horizontal exceeds 200W/m2 at 
which point they will turn OFF. If they are OFF, they will stay OFF 
until the solar on the horizontal falls below 120W/m2. The negative 
numbers are there because the controller is designed to be a 
differential controller (ie watching the difference between two values 
instead of comparing absolute values. With a set point of 0 (the "upper 
input value" in this case) the negative numbers are just there to make 
the "turn on" and "turn off" input value differences work out correctly.
Kind regards,

On 3/24/2014 05:29, Frédéric Oleksandrow wrote:
> Dear all,
> I don't understand how the artificial lighting in the Trnsys 17 works.
> As I can see, there is a controller with some input values, like 
> « upper » and « lower dead band ». But in the native examples of 
> trnsys 17, these inputs are not configured.
> Moreover, there is nothing to say what is the level of intensity 
> required to switch off the artificial lighting inside the room.
> (What is the minimum "lux" value inside the room ?)
> And finally, for the value (-120) * 3.6 in ITLIGHTON, where is it 
> taken into account ? Why is it a negative value ?
> Could you please help me to better understand and control these things ?
> Best regards,
> ir. Frédéric Oleksandrow
> *E.W.A. Engineering*
> BE 0545.866.807
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at cae.wisc.edu
> https://mailman.cae.wisc.edu/listinfo/trnsys-users

Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

d.bradley at tess-inc.com


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/trnsys-users-onebuilding.org/attachments/20140326/e44f02fd/attachment-0001.htm>

More information about the TRNSYS-users mailing list