[Equest-users] How does eQuest know initialFootcandlesforDaylighting Calc?

Vikram Sami VSami at lasarchitect.com
Fri Jan 8 13:53:25 PST 2010


The newer versions of eQUEST have  an illuminance method to define your
lighting data where you set your desired footcandle level that might be
what you are looking for. I haven't used it yet, but it allows you to
set up a lighting system and footcandle level, and calculates the
lighting power from that. It is slightly different from what you are
talking about in the sense that it doesn't calculate the footcandles
from a designed scheme, but goes the other way. 





From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of John
Sent: Thursday, January 07, 2010 12:02 PM
To: Matutinovic, Luka; Nick Caton; R B
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] How does eQuest know
initialFootcandlesforDaylighting Calc?




That was my hope, but eQuest isn't that smart. As I was so directed by
an "unimpeachable source", there IS no footcandle level until you set it
in the Daylighting mode. eQuest then assumes that this is the level 100%
of the lights emit. Then when you allow the Daylighting mode to run,
eQuest lowers the % lighting based on how much you can gain from the
skylights, side daylighting, etc.


Crude but straight forward.


Others can add or correct..


John R. Aulbach, PE, CEM

Senior Energy Engineer


Partner Energy

1990 E. Grand Avenue, El Segundo, CA 90245
W: 888-826-1216, X254| D: 310-765-7295 | F: 310-817-2745

www.ptrenergy.com <http://www.ptrenergy.com/>  | jaulbach at ptrenergy.com
<mailto:%7C%20jaulbach at ptrenergy.com> 




From: "Matutinovic, Luka" <LMatutinovic at halsall.com>
To: Nick Caton <ncaton at smithboucher.com>; R B <slv3sat at gmail.com>; John
Aulbach <jra_sac at yahoo.com>
Cc: equest-users at lists.onebuilding.org
Sent: Thu, January 7, 2010 6:09:14 AM
Subject: RE: [Equest-users] How does eQuest know initial
FootcandlesforDaylighting Calc?


Does this mean that there is some "baseline" fc that is provided by the
electrical lighting?  That is to say, eQuest will determine how many fc
daylight provides and satisfy the rest with some fraction of the
installed LPD?  This implies that there is a relationship between LPD
and fc, is that true and if so what is it or where could I find it?

Luka Matutinovic, B.A.Sc., LEED(r) AP
Green Building Consultant 

T. 416.644.0649
F. 416.487.9766  
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-----Original Message-----
From: Nick Caton [mailto:ncaton at smithboucher.com] 
Sent: Wednesday, December 30, 2009 10:27 AM
To: R B; John Aulbach
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] How does eQuest know initial
FootcandlesforDaylighting Calc?

The DOE2 help files suggest, if not directly, that the sensor you are
placing is measuring ONLY "illuminance due to daylight," in isolation of
any electrical lighting in the project.  When you define a "target"
illumation level (say 30fc) at a specific point/orientation, that sensor
will plot the daylight measured in the same vector against a curve
(specified when you select dimming control options) to determine a
factor to apply to the zone's Lightig Watts/SF.

To my knowledge, eQuest in no manner whatsoever is attempting to perform
the operations of photometric software (AGI32/Visual/LightPRO/etc).


25501 west valley parkway
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-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of R B
Sent: Monday, December 28, 2009 4:44 PM
To: John Aulbach
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] How does eQuest know initial Footcandles
forDaylighting Calc?

My guess is that the tool assumes the lighting wattage that you have
gives the amount of footcandles specified. If 50% of this is from
daylight, then remaining is from 50% of the installed lighting
(translating into 50% wattage usage).

On 12/28/09, John Aulbach <jra_sac at yahoo.com> wrote:
> LIke the Phantom of the Opera.."A mystery never fully explained.."
> I have performed Daylighting savings EEMs in eQuest, where one places
> sensor in the space, one deliniates a minimum footcandle requirement,
> runs a Parametric run to determine how much lighting energy may be
> What is NOT clear to me is how eQuest determines what the inital
> level is. It obviously knows the lighting fixture height (Ceilling or
> syspended) and the geometry of existing windows, etc. But I cannot
> where the information lies that says "eQuest assumes so many
lumens/watt of
> certain lighting."
> Can anyone "ILLUMINATE" me, please?
> Hope all had a great Christmas.
> John Aulbach
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