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Erik, Joe and others,<br><br>
This all makes a whole lot more sense now and I guess I didn't dig far
enough to realize the limitation when I started the investigation. It
seems like the my best bet now is to switch to EnergyPlus or TRNSYS (we
have both programs).<br><br>
That said, I am thinking that since the change in HVAC electricity
consumption I have right now is strictly due to decrease in occupancy
(less people as internal load, less people = less ventilation, and higher
set point), I should be able to isolate the effect of the set point
alone, although not to the detail (to each components, such as walls,
windows, etc) I wanted.<br><br>
I should be able to get the reduction from the occupancy internal loads
by running two base case with same set-point, then I should be able to
get the energy consumption differences by ventilation from the CFM per
person (or sqft) assumption. The total energy consumption changes less
these two items should give me energy consumption "saved" by
adjusting the set-point.<br><br>
But still, I'd better off and get more info I want if I move to energy
plus now, and I will probably go to that route<br><br>
thanks all<br><br>
- James<br><br>
At 07:38 AM 10/5/2009, Erik Olsen wrote:<br>
<blockquote type=cite class=cite cite="">James, this is a good
illustration of the limitations of DOE2. The input won't be as
easy, but life may be easier (and more accurate) in this case if you
switch to a simulation engine that includes a true heat balance model
(EnergyPlus, TRNSYS, ESP-r). These are more frequently used for
investigations of dynamic building physics.<br><br>
Regards,<br>
Erik<br><br>
<font size=1>Erik Olsen, PE<br>
212 219 2255<br>
| <a href="mailto:olsen@transsolar.com">olsen@transsolar.com</a><br>
Transsolar Inc. | 134 Spring St. Suite 601 | New York, NY 10012<br><br>
Transsolar Climate Engineering<br>
Technical consulting for energy efficiency and environmental quality in
buildings<br>
New York - Stuttgart - Munich</font> <br><br>
<br>
Joe Huang wrote: <br>
<blockquote type=cite class=cite cite=""><div
class="moz-text-flowed" style="font-family:
-moz-fixed">James, <br><br>
It's good to see that you're getting a lot of help in answering your
<br>
questions. I'm sorry if my original answer was too brief to explain <br>
the situation. Here are some additional thoughts: <br><br>
1. The differences between LOADS and SYSTEM loads. You can think of <br>
LOADS loads as the heat flows into and out of the space at a user defined
constant temperature. In SYSTEM, DOE-2 models the effect of <br>
those heat flows, plus the actions of the HVAC system, to determine <br>
the true temperature of the zone and the loads imposed or met by the HVAC
system. Thus, set point changes will not affect the LOADS loads, <br>
but occupancy changes should have an effect by changing the internal
<br>
heat gain from occupants (but not the fresh air amount which is
considered a SYSTEM action). <br><br>
2. Deriving the component loads at the SYSTEM level. This is something
<br>
I've looked into for many years. As you've mentioned in another e-mail,
<br>
component loads are available only for LOADS, since SYSTEM deals only
<br>
with the aggregated loads for the entire zone. The component loads in
LOADS, however, are calculated at the fixed reference temperature, and
<br>
not the true zone temperature. You can make a UA-delta T adjustment of
the LOADS loads for this difference in zone temperature, but this will
<br>
still not account for the pick-up loads in the morning, nor tell you what
to do with those loads when the HVAC system is off. <br><br>
Joe Huang <br>
White Box Technologies <br>
346 Rheem Blvd. Suite 108D <br>
Moraga CA 94556 <br>
<a href="mailto:yjhuang@whiteboxtechnologies.com">
yjhuang@whiteboxtechnologies.com</a> <br><br>
James Lo wrote: <br>
<blockquote type=cite class=cite cite="">John, <br><br>
Thanks for the info, but the procedure you described IS what we have been
doing. The loads from the report you showed do NOT vary when occupancy
and set point change, hence the problem. These loads only change (from
LOADS described from others) when building geometry, materials and other
building envelope parameters change. <br><br>
hopefully I am making sense... <br><br>
thanks <br><br>
- James <br><br>
At 02:45 PM 10/2/2009, Grando, John wrote: <br>
<blockquote type=cite class=cite cite="">James, <br><br>
You can create an hourly report output for this and then sum the results
in Excel. Go to the "projects and site" tab, double click
on the hourly report, and add a new block. Make it look like the
picture attached. Run the model and then go to file>export
hourly results. You will then have a .csv file with the hourly
loads. You can also do this for each thermal zone you created. <br><br>
<br><br>
John Grando LEED AP| Mechanical Engineer <br>
Phone: 212-615-3705 | Fax: 212-615-3700 <br>
<a href="mailto:jgrando@cosentini.com">jgrando@cosentini.com</a>
<br><br>
Cosentini Associates - A Tetra Tech Company <br>
Two Pennsylvania Plaza - Third Floor - New York, NY 10121 <br>
<a href="http://www.cosentini.com">www.cosentini.com</a> <br><br>
<br><br>
-----Original Message----- <br>
From:
<a href="mailto:bldg-sim-bounces@lists.onebuilding.org">
bldg-sim-bounces@lists.onebuilding.org</a>
[<a href="mailto:bldg-sim-bounces@lists.onebuilding.org" eudora="autourl">
mailto:bldg-sim-bounces@lists.onebuilding.org</a>] On Behalf Of James Lo
<br>
Sent: Friday, October 02, 2009 3:37 PM <br>
To: Jeff Haberl; Joe Huang <br>
Cc:
<a href="mailto:bldg-sim@lists.onebuilding.org">
bldg-sim@lists.onebuilding.org</a> <br>
Subject: Re: [Bldg-sim] eQuest/DOE2 instantaneous loads <br><br>
Thanks Dr. Haberl and Nikola for the info, and it's clear now what the
DOE2 file definitions are <br><br>
The big question remains tho: <br><br>
1. LOADS loads are calculated based on components of the buildings
(window, wall, roof, etc) and these are design loads 2. SYSTEM loads are
summarized loads subjected to the HVAC system, so these are
"operation" loads <br><br>
SYSTEM loads are not separate back into components, only total loads are
present. <br><br>
So my questions is really whether there is a way for me to break the
SYSTEM loads back into components?, ie, x% of SYSTEM cooling load for
month z is from wall conduction, y% is from window radiation, etc.
<br><br>
Is this even doable? hopefully I am making sense to you guys... <br><br>
thanks! <br><br>
- James <br><br>
At 01:42 PM 10/2/2009, Jeff Haberl wrote: <br>
>"SYSTEMS" outputs will be labeled SV or SS. <br>
> <br>
>"LOADS" outputs will be labeled LV or LS, in the upper left
corner of <br>
>the page. <br>
> <br>
>"PLANT" outputs will be labeled PV or PS. <br>
> <br>
>Jeff <br>
> <br>
> <br>
>8=! 8=) :=) 8=) ;=) 8=) 8=(
8=) 8=() 8=) 8=| 8=) :=') 8=)8=?
<br>
> <br>
>Jeff S. Haberl, Ph.D.,P.E.,
<a href="mailto:FASHRAE..............jhaberl@tamu.edu">
FASHRAE..............jhaberl@tamu.edu</a> <br>
> <br>
>Professor............................................................Of
<br>
>fice <br>
>Ph: 979-845-6507 <br>
> <br>
>Department of Architecture.............................Lab <br>
>Ph:979-845-6065 <br>
> <br>
>Energy Systems Laboratory.............................FAX:
979-862-2457 <br>
> <br>
>Texas A&M
University.....................................77843-3581 <br>
> <br>
>College Station, Texas, USA, <br>
>77843..................URL:www.esl.tamu.edu <br>
> <br>
>8=/ 8=) :=) 8=) ;=) 8=)
8=() 8=) :=) 8=) 8=! 8=) 8=? 8=)8=0
<br>
>________________________________________ <br>
>From:
<a href="mailto:bldg-sim-bounces@lists.onebuilding.org">
bldg-sim-bounces@lists.onebuilding.org</a> <br>
>[<a href="mailto:bldg-sim-bounces@lists.onebuilding.org">
bldg-sim-bounces@lists.onebuilding.org</a>] On Behalf Of James Lo <br>
>[<a href="mailto:ljameslo@gmail.com">ljameslo@gmail.com</a>] <br>
>Sent: Friday, October 02, 2009 1:35 PM <br>
>To: Joe Huang <br>
>Cc:
<a href="mailto:bldg-sim@lists.onebuilding.org">
bldg-sim@lists.onebuilding.org</a> <br>
>Subject: Re: [Bldg-sim] eQuest/DOE2 instantaneous loads <br>
> <br>
>Joe, <br>
> <br>
>Since we are only novice users here and only using the eQuest as our
<br>
>interface, I am not familiar with the DOE2 output file well enough to
<br>
>isolate the SYSTEM loads. (any pointers on the file definition will
be great). <br>
> <br>
>That said, from what we can tell, the system loads (making sure I am
<br>
>not misunderstand you here), such as total cooling coil output, does
<br>
>reflect the changes we make. That said, since I am trying to separate
<br>
>them out into gains from walls/window, etc, I was looking into the
loads side. <br>
> <br>
>I assume there must be some outputs from DOE2 file which eQuest is
<br>
>reading from which describe what I am looking for. <br>
> <br>
>Any additional help will be awesome. <br>
> <br>
>thanks everyone <br>
> <br>
>- James <br>
> <br>
>At 12:40 PM 10/2/2009, Joe Huang wrote: <br>
> >James, <br>
> > <br>
> >There are two sets of loads in DOE-2, in both the LOADS and
SYSTEMS <br>
> >routines. Make sure you're looking at the SYSTEMS loads, not the
<br>
> >LOADS loads. <br>
> > <br>
> >Joe Huang <br>
> >White Box Technologies, Inc. <br>
> >346 Rheem Blvd. Suite 108D <br>
> >Moraga CA 94556 <br>
>
><a href="mailto:YJHuang@whiteboxtechnologies.com">
YJHuang@whiteboxtechnologies.com</a> <br>
> <br>
>_______________________________________________ <br>
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