Re: [TRNSYS-users] Artificial lighting

[David BRADLEY <d.bradley@tess-inc.com>]

Frédéric
  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,
 David

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

 

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