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I agree, the tool must suit the application. My intended message is
that you can use equest for daylighting, but you need to be aware that
equest is will produce the results based on the user's input - garbage
in, garbage out. One needs to take into account occupant
behaviour. I feel it is better to use a equest/DOE2.1 for
daylighting savings as it captures the actual lighting demand peak but I
tend to adjust my doe2 models to achieve a lighting power reduction
similar to what you would see if you used the PAF factors listed in
Appendix G. <br><br>
<br><br>
At 05:51 PM 23/08/2010, you wrote:<br>
<blockquote type=cite class=cite cite="">It’s not my intent to “take
sides” or anything, but a curious reader (me) might ask “What do you use,
Chris?” <br>
<br>
As I’m pointing out – a saving grace of eQuest/DOE2.2 is that you can
spoon-feed whatever scheduling you may have generated in an outside
program if you don’t like what you’re seeing. I understand some
distrust eQuest’s results enough to regularly use DAYsim to generate
custom scheduling. In my practice, I’ve found it more
time-efficient to work within and around the known limitations of eQuest,
for the sort of energy modeling I’m regularly tasked with. I also
prefer to use other software packages to model instantaneous daylighting
behavior – anyone interested, see archives.<br>
<br>
I do think it’s a bit of a stretch however to claim the hourly modeled
daylighting behavior of eQuest is comparably dumbed-down as a blanket
percentage reduction, as we do with LPD’s for occupancy sensors under
90.1 (I think that’s what you’re referencing) – eQuest’s current
capabilities do allow an end-user to effectively compare multiple custom
daylighting control strategies and their resultant effects on the rest of
a building’s systems (i.e. heating/cooling) in a time-efficient
fashion.<br>
<br>
I’m not disagreeing the DOE2.1e algorithms aren’t the best for figuring
how many fc are incident in a given space for a given hour, but
statements that boil down to “eQuest sucks for daylighting” (for LEED
modeling or otherwise) can certainly be misleading. If you can take
what’s known to be inaccurate into account, you can realize eQuest as a
pretty useful tool for designing with daylighting.<br>
<br>
~Nick<br>
<img src="cid:.0" width=119 height=37 alt="cid:489575314@22072009-0ABB">
<br>
<b> <br>
NICK CATON, E.I.T.<br>
</b>PROJECT ENGINEER<br>
25501 west valley parkway<br>
olathe ks 66061<br>
direct 913 344.0036<br>
fax 913 345.0617<br>
<i>Check out our new web-site @
</i><a href="www.smithboucher.htm">www.smithboucher.com</a><u> <br>
</u> <br>
<b>From:</b> Chris Jones
[<a href="mailto:cj@enersave.ca" eudora="autourl">
mailto:cj@enersave.ca</a>] <br>
<b>Sent:</b> Monday, August 23, 2010 4:03 PM<br>
<b>To:</b> Nick Caton; equest-users@lists.onebuilding.org<br>
<b>Subject:</b> Re: [Equest-users] Modeling Light Shelves for Reduction
inCooling/Heating Load?<br>
<br>
Equest, like DOE2.1e before it provides very generous estimates of the
lighting energy saved using daylighting controls. I believe that
taking equest predictions at face value for LEED models would be
inaccurately providing more benefit than warranted. The Appendix G
power factor ratings are likely not conservative in some cases. I
wouldn't expect to see any more benefit using equest's daylighting than I
would using the Appendix G power factor adjustments.<br><br>
A paper that attempted to explore various daylighting energy reduction
savings modelling strategies. DOE2.1e and Daysim are the two
programs used for the analysis.<br>
<a href="http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc46761/nrcc46761.pdf">
http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc46761/nrcc46761.pdf<br><br>
<br>
</a>At 03:49 PM 23/08/2010, you wrote:<br><br>
Content-class: urn:content-classes:message<br>
Content-Type: multipart/related;<br>
boundary="----_=_NextPart_001_01CB42FC.41DFF80A";<br>
type="multipart/alternative"<br><br>
Perhaps these are the answers you’re seeking:<br>
1. Building shades and their
respective reflectance properties do affect the modeled behavior of space
daylighting systems in eQuest models. Be sure to pay close
attention to all three values (and their associated help files) on the
right of the following image – they may all play a part depending on what
exactly you’re trying to model.<br>
<img src="cid:7.1.0.9.2.20100824091411.046f96c8@enersave.ca.3" width=592 height=441 alt="[]">
<br>
2. Based on your query, a
caution: eQuest’s results do not have any inherent degree of
accuracy/in-accuracy with regard to the modeled energy consumption
resulting from daylighting controls – that depends pretty much entirely
on how closely you define the daylighting systems’ behavior to
reality. If you have a program which you perceive to be producing
more accurate hourly percentage consumptions for your spaces, then by all
means – there’s nothing stopping you from defining a schedule in eQuest
to match the other program’s results. <br>
<br>
I expect you mean to say you’re utilizing another program to accurately
determine the behavior of daylight in response to adding/modifying light
shelves, but if you are indeed using another program to determine annual
hourly behavior with a weather file, I’d be very interested to hear more
about it!<br>
<br>
Best of luck,<br>
<br>
~Nick<br>
<br>
<img src="cid:.0" width=119 height=37 alt="cid:489575314@22072009-0ABB">
<br>
<b> <br>
NICK CATON, E.I.T.<br>
</b>PROJECT ENGINEER<br>
25501 west valley parkway<br>
olathe ks 66061<br>
direct 913 344.0036<br>
fax 913 345.0617<br>
<i>Check out our new web-site @
</i><a href="www.smithboucher.htm">www.smithboucher.com</a><u> <br>
</u> <br>
<b>From:</b> equest-users-bounces@lists.onebuilding.org [
<a href="mailto:equest-users-bounces@lists.onebuilding.org" eudora="autourl">
mailto:equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of
</b>Nilay R. Desai<br>
<b>Sent:</b> Monday, August 23, 2010 11:35 AM<br>
<b>To:</b> equest-users@lists.onebuilding.org<br>
<b>Subject:</b> [Equest-users] Modeling Light Shelves for Reduction
inCooling/Heating Load?<br>
<br>
E.G. Would it be accurate to model an external light shelve as a
horizontal building shade with a high reflectance value on the skyward
facing surface? I understand the day lighting benefit in Equest would be
inaccurate, but we are using separate software to obtain accurate day
lighting results. Thanks!<br>
<br>
<br>
Nilay Desai<br>
P 626.351.8881 Ext. 237<br>
<a href="mailto:klowe@tmadtg.com">ndesai@ttgcorp.com</a><br>
<br><br>
<br>
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<br>
Chris Jones<br>
14 Oneida Avenue<br>
Toronto, ON M5J 2E3.<br>
Tel. 416-203-7465<br>
Fax. 416-946-1005<br><br>
</blockquote>
<x-sigsep><p></x-sigsep>
<br>
Chris Jones<br>
14 Oneida Avenue<br>
Toronto, ON M5J 2E3.<br>
Tel. 416-203-7465<br>
Fax. 416-946-1005<br><br>
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