[Equest-users] Daylighting and heating penalty

Scott Hackel shackel at ecw.org
Mon Dec 1 12:29:39 PST 2008

Thanks for the reply John.  But, I haven't changed anything about the glazing between the two runs - solar gain through the windows should be unchanged.  All I did change was the controls on the lights.

If you do have a chance to look at my model I'd be happy to hear any additional thoughts.  Thanks again -


Message: 2
Date: Mon, 1 Dec 2008 11:56:49 -0800
From: "Aulbach, John" <jaulbach at nexant.com>
Subject: Re: [Equest-users] Daylighting and heating penalty
To: "Scott Hackel" <shackel at ecw.org>,
        <equest-users at lists.onebuilding.org>
        <99A2815FF4D295488E034407278B16A4025C0EDF at sacexm01.nexant.corp>
Content-Type: text/plain; charset="us-ascii"


Just a quick shot. You may decreasing lighting (and thus not getting the
heating energy provided by that light), but you are certainly adding a
bunch more in solar gain. Being originally from Chicago, I remember
sitting in my parent's car in the dead of winter, but wanting to take my
coat off with the full winter sun shining into the car windows.

I will see about looking at your model later.

John R. Aulbach, PE, CEM
Project Manager
Nexant, Inc.
701 West Kimberly Ave., Suite 245
Placentia, CA 92870-6342 USA
Phone: 714-524-4402
Fax: 714-524-4407
email: jaulbach at nexant.com


From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Scott
Sent: Monday, December 01, 2008 11:30 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Daylighting and heating penalty

I have noticed that on a couple of my eQUEST models, when daylighting is
used, that turning the daylighting controls on creates a small reduction
in heating energy.  Intuition (and a number other modeling projects)
suggests that the opposite should occur; when daylighting is implemented
the decrease in lighting energy should create an increase in heating
energy.  In my model this occurs largely in the winter months, so it is
not likely to be due to reheat effects.  And the load component reports
do not reveal this increase, so I don't know what part of the load is

In one example, I'm doing a small daylighting study on a typical office
unit in Wisconsin...I've attached the .inp and .pd2 files for your
review.  I have turned daylighting on in parametric run #7, if you'd
like to compare that with the baseline.  If anyone sees a quirk in my
model setup, or feels there's some good reason that eQUEST would give
this result, I'd be happy to hear your thoughts.  Thanks for your time -

Scott Hackel

Project Manager


Energy Center of Wisconsin

455 Science Drive, Suite 200

Madison, WI  53711

608.238.8276  x129

shackel at ecw.org


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