Re: [EnergyPlus_Support] daylighting: dimmers vrs on/off controls

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

Which control types were you comparing?

One of the defaults for control type 1 (Continuous dimming) control is 

    0.3, !- Minimum input power fraction for continuous dimming control

This means the lights will always consume at least 30% of full power - they 
will never turn off completely.  This could produce the result you are seeing.  
Control type 3 (continuous/off) will turn the lights off completely above the  
illuminance setpoint.

By "on/off" do you mean control type 2 (stepped) with 0 steps?

If you compare type 3 (continuous/off) vs. type 2 (with 0 steps), you should 
get the result you expect.  Turn on REPORT VARIABLE "Ltg Power Multiplier from 
Daylighting" to see how the daylighting controls are working.

Mike


On 18 Mar 2005, at 11:50, Chris Jones wrote:

> 
> The trick with daylighting control is to try to predict the occupants 
> behavior and reactions to the lighting control.  In general, the setpoint 
> for on/off lighting control has to be significantly higher (more 
> footcandles) than for continuous dimming control.  Occupants dislike a 
> system that switches on and off many times a day.
> 
> The other factor is interior shades on the windows.  If they are occupant 
> controlled, how do they affect the daylighting control when closed?  When 
> do the occupants close the shades and do they open them again before the 
> end of the day?
> 
> Dr. Christoph Reinhart at the National Research Council in Ottawa has done
> considerable research in this area.  You might want to contact him - 
> Christoph.Reinhart@xxxxxxxxxxxxxx.
> 
> 
> At 08:45 3/18/2005, you wrote:
> 
> 
> >Hi!
> >
> >Has anybody done an overall energy consumption comparison between
> >dimmers and lights that go on/off?
> >
> >I made one, and it resulted with on/off controls being more energy-
> >saving than dimmers (the E+ defaults were left intact, I only
> >changed the control type). While logic might say that dimmers would
> >consume less energy, I would like to know if I am in the right track.
> >
> >My simulation took into account also heating and cooling year round.
> >
> >Thanks!
> >
> >
> >
> >
> >
> >The primary EnergyPlus web site is found at:
> >http://www.energyplus.gov
> >
> >The group web site is:
> >http://groups.yahoo.com/group/EnergyPlus_Support/
> >
> >Attachments are not allowed -- please post any files to the appropriate 
> >folder in the Files area of the Support Web Site.
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> 
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Chris Jones
> EnerSys Analytics Inc.
> 14 Oneida Avenue
> Toronto, ON M5J-2E3
> Tel. 416 203-7465
> Fax. 416 946-1005  
> 
> 
> 
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
> 
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
> 
> Attachments are not allowed -- please post any files to the appropriate folder
> in the Files area of the Support Web Site.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 
> 
> 
> 
> 



========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx




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