Re: [EnergyPlus_Support] Illuminance at reference point

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

Correct.  EnergyPlus does not model the illuminance from the LIGHTS.  
EnergyPlus assumes that the design lighting level meets or beats the 
illuminance setpoint.

For the winter design day, it is customary in the USA for some designers to 
assume no sun (and no internal loads) for a worst case winter heating 
condition.  In other parts of the world, this may be overly conservative.  
Certainly for a daylighting analysis, the clearness must be set to a more 
typical value in the 0.8 to 1.1 range.  With clearness=0, you are correct that 
daylighting will all be zero and have no impact on the simulation. 

Mike


On 27 Apr 2005, at 17:41, Fábyo Luiz Pereira wrote:

> 
> Dear all,
> 
>    I'm doing a winter design day simulation where are considered two cases with
> same lights design level (power): one with daylighting control and other without
> daylighting control. For both, the heating power required is exactly the same.
> Two questions:
> 
> - Since the daylight detailed analysis basically measures the Sun light
> transmitted by windows, there is no way to measure the illuminance from lights?
> 
> - For winter design day, since ASHRAE consider that sky clearness is zero
> (completely cloudy), it is no reason to use the daylight analysis?
> 
>    Thank you!
> 
> ________________________________________________________
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>  UFRGS - Laboratório de Vapor e Refrigeração
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========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx




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