Re: [EnergyPlus_Support] Illuminance measurement

["Michael J. Witte" <mjwitte@xxxxxxxx>]

In the Engineering Reference, see the section "Lighting Control System 
Simulation", starting on p. 125 (pdf p. 153, v1.2.2).  The key statement is:

"This relationship assumes that the electric lights at full power produce an 
illuminance equal to Iset at the reference point."

EnergyPlus does not simulate the light output of the electric lighting.  The 
lighting is controlled only by the illuminance provided by daylighting at the 
reference point(s).  This available illuminance is then entered into the 
control relationship depending on the control type and a lighting power 
fraction is calculated.  So it is assumed that the daylighting sensor cannot 
see any output from the artificial lights.  How this would be done physically, 
I do not know, I am not familiar with actual daylighting controls.

Mike




On 4 May 2005, at 23:14, Fábyo Luiz Pereira wrote:

>    Dear all,
> 
>    How is determined the "Ltg Power Multiplier from Daylighting" if the
> daylight sensors only measures daylight illuminance? I mean, where is measured
> the artificial illuminance from lights? This is measured (calculated by E+) but
> can't be reported?
> 
>    For example, if I want 500 lux in one environment and the sensor is
> measuring 400 lux, lights will contribute with 100 lux. This artificial
> illuminance to reach the 500 lux is given by E+ as lights electric consumption.
> So, if the electric consumption fluctuates all day long, and in fact this
> happens, means that daylight illuminance is fluctuating.
> 
>    Thanks!
> 
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========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx




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