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Hi Joe,<br>
<br>
Agreed, there is a bookkeeping problem if the goal is to assign
specific gains occurring at one point in time to mechanical loads
occuring at another point in time. My point is only that a heat
balance model should make it easier to study the instantaneous
convective gains from individual surfaces and radiative exchange
between surfaces, and that it can allow a true morning start-up or
drift down at night.<br>
<br>
Erik<br>
<br>
Joe Huang wrote:
<blockquote cite="mid:4ACA4F23.2020108@drawbdl.com" type="cite">
<pre wrap="">Erik,
I don't agree with your assumption that going to a heat balance model
will "make life easier" for James' needs. From my experience, getting
the "component loads" from EnergyPlus is even more difficult than with
DOE-2. About 8 years ago, there was a DOE project that tried to extract
component loads from EnergyPlus that found the task quite complicated
and convoluted.
In the final analysis, a "component load" is an abstraction,
since the HVAC system is responding to zone-level heat gains or losses
that have built up over many hours. For example, when the air
conditioner kicks
on in the midmorning, is that "load" due to the solar through the windows,
the lights that came on, or the fresh air supplied over the past three
hours?
On the flip side, when the heating comes on at night in the Fall, is that
"load" attributable only to the cumulative envelope heat losses and how
should it be offset by solar heat gain and internal loads built up during
the day?
These are bookkeeping problems that extend beyond simply switching to
a heat balance model.
Joe Huang
White Box Technologies
346 Rheem Blvd. Suite 108D
Moraga CA 94556
Erik Olsen wrote:
</pre>
<blockquote type="cite">
<pre wrap=""> 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.
Regards,
Erik
Erik Olsen, PE
212 219 2255 | <a class="moz-txt-link-abbreviated" href="mailto:olsen@transsolar.com">olsen@transsolar.com</a> <a class="moz-txt-link-rfc2396E" href="mailto:olsen@transsolar.com"><mailto:olsen@transsolar.com></a>
Transsolar Inc. | 134 Spring St. Suite 601 | New York, NY 10012
Transsolar Climate Engineering
Technical consulting for energy efficiency and environmental quality in
buildings
New York - Stuttgart - Munich
Joe Huang wrote:
</pre>
<blockquote type="cite">
<pre wrap=""><div class="moz-text-flowed" style="font-family: -moz-fixed">James,
It's good to see that you're getting a lot of help in answering your
questions. I'm sorry if my original answer was too brief to explain
the situation. Here are some additional thoughts:
1. The differences between LOADS and SYSTEM loads. You can think of
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
those heat flows, plus the actions of the HVAC system, to determine
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,
but occupancy changes should have an effect by changing the internal
heat gain from occupants (but not the fresh air amount which is
considered a SYSTEM action).
2. Deriving the component loads at the SYSTEM level. This is something
I've looked into for many years. As you've mentioned in another e-mail,
component loads are available only for LOADS, since SYSTEM deals only
with the aggregated loads for the entire zone. The component loads in
LOADS, however, are calculated at the fixed reference temperature, and
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
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.
Joe Huang
White Box Technologies
346 Rheem Blvd. Suite 108D
Moraga CA 94556
<a class="moz-txt-link-abbreviated" href="mailto:yjhuang@whiteboxtechnologies.com">yjhuang@whiteboxtechnologies.com</a>
<a class="moz-txt-link-rfc2396E" href="mailto:yjhuang@whiteboxtechnologies.com"><mailto:yjhuang@whiteboxtechnologies.com></a>
James Lo wrote:
</pre>
<blockquote type="cite">
<pre wrap="">John,
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.
hopefully I am making sense...
thanks
- James
At 02:45 PM 10/2/2009, Grando, John wrote:
</pre>
<blockquote type="cite">
<pre wrap="">James,
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.
John Grando LEED AP| Mechanical Engineer
Phone: 212-615-3705 | Fax: 212-615-3700
<a class="moz-txt-link-abbreviated" href="mailto:jgrando@cosentini.com">jgrando@cosentini.com</a> <a class="moz-txt-link-rfc2396E" href="mailto:jgrando@cosentini.com"><mailto:jgrando@cosentini.com></a>
Cosentini Associates - A Tetra Tech Company
Two Pennsylvania Plaza - Third Floor - New York, NY 10121
<a class="moz-txt-link-abbreviated" href="http://www.cosentini.com">www.cosentini.com</a> <a class="moz-txt-link-rfc2396E" href="http://www.cosentini.com"><http://www.cosentini.com></a>
-----Original Message-----
From: <a class="moz-txt-link-abbreviated" href="mailto:bldg-sim-bounces@lists.onebuilding.org">bldg-sim-bounces@lists.onebuilding.org</a>
<a class="moz-txt-link-rfc2396E" href="mailto:bldg-sim-bounces@lists.onebuilding.org"><mailto:bldg-sim-bounces@lists.onebuilding.org></a>
[<a class="moz-txt-link-freetext" href="mailto:bldg-sim-bounces@lists.onebuilding.org">mailto:bldg-sim-bounces@lists.onebuilding.org</a>] On Behalf Of James Lo
Sent: Friday, October 02, 2009 3:37 PM
To: Jeff Haberl; Joe Huang
Cc: <a class="moz-txt-link-abbreviated" href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a>
<a class="moz-txt-link-rfc2396E" href="mailto:bldg-sim@lists.onebuilding.org"><mailto:bldg-sim@lists.onebuilding.org></a>
Subject: Re: [Bldg-sim] eQuest/DOE2 instantaneous loads
Thanks Dr. Haberl and Nikola for the info, and it's clear now what
the DOE2 file definitions are
The big question remains tho:
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
SYSTEM loads are not separate back into components, only total loads
are present.
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.
Is this even doable? hopefully I am making sense to you guys...
thanks!
- James
At 01:42 PM 10/2/2009, Jeff Haberl wrote:
</pre>
<blockquote type="cite">
<pre wrap="">"SYSTEMS" outputs will be labeled SV or SS.
"LOADS" outputs will be labeled LV or LS, in the upper left corner of
the page.
"PLANT" outputs will be labeled PV or PS.
Jeff
8=! 8=) :=) 8=) ;=) 8=) 8=( 8=) 8=() 8=) 8=| 8=) :=')
</pre>
</blockquote>
<pre wrap="">8=)8=?
</pre>
<blockquote type="cite">
<pre wrap="">Jeff S. Haberl, Ph.D.,P.E., <a class="moz-txt-link-abbreviated" href="mailto:FASHRAE..............jhaberl@tamu.edu">FASHRAE..............jhaberl@tamu.edu</a>
</pre>
</blockquote>
<pre wrap=""><a class="moz-txt-link-rfc2396E" href="mailto:FASHRAE..............jhaberl@tamu.edu"><mailto:FASHRAE..............jhaberl@tamu.edu></a>
</pre>
<blockquote type="cite">
<pre wrap="">Professor............................................................Of
</pre>
</blockquote>
<blockquote type="cite">
<pre wrap="">fice
Ph: 979-845-6507
Department of Architecture.............................Lab
Ph:979-845-6065
Energy Systems Laboratory.............................FAX:
</pre>
</blockquote>
<pre wrap="">979-862-2457
</pre>
<blockquote type="cite">
<pre wrap="">Texas A&M University.....................................77843-3581
College Station, Texas, USA,
77843..................URL:www.esl.tamu.edu
8=/ 8=) :=) 8=) ;=) 8=) 8=() 8=) :=) 8=) 8=! 8=) 8=?
</pre>
</blockquote>
<pre wrap="">8=)8=0
</pre>
<blockquote type="cite">
<pre wrap="">________________________________________
From: <a class="moz-txt-link-abbreviated" href="mailto:bldg-sim-bounces@lists.onebuilding.org">bldg-sim-bounces@lists.onebuilding.org</a>
</pre>
</blockquote>
<pre wrap=""><a class="moz-txt-link-rfc2396E" href="mailto:bldg-sim-bounces@lists.onebuilding.org"><mailto:bldg-sim-bounces@lists.onebuilding.org></a>
</pre>
<blockquote type="cite">
<pre wrap="">[<a class="moz-txt-link-abbreviated" href="mailto:bldg-sim-bounces@lists.onebuilding.org">bldg-sim-bounces@lists.onebuilding.org</a>
</pre>
</blockquote>
<pre wrap=""><a class="moz-txt-link-rfc2396E" href="mailto:bldg-sim-bounces@lists.onebuilding.org"><mailto:bldg-sim-bounces@lists.onebuilding.org></a>] On Behalf Of James Lo
</pre>
<blockquote type="cite">
<pre wrap="">[<a class="moz-txt-link-abbreviated" href="mailto:ljameslo@gmail.com">ljameslo@gmail.com</a> <a class="moz-txt-link-rfc2396E" href="mailto:ljameslo@gmail.com"><mailto:ljameslo@gmail.com></a>]
Sent: Friday, October 02, 2009 1:35 PM
To: Joe Huang
Cc: <a class="moz-txt-link-abbreviated" href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a>
</pre>
</blockquote>
<pre wrap=""><a class="moz-txt-link-rfc2396E" href="mailto:bldg-sim@lists.onebuilding.org"><mailto:bldg-sim@lists.onebuilding.org></a>
</pre>
<blockquote type="cite">
<pre wrap="">Subject: Re: [Bldg-sim] eQuest/DOE2 instantaneous loads
Joe,
Since we are only novice users here and only using the eQuest as our
interface, I am not familiar with the DOE2 output file well enough to
isolate the SYSTEM loads. (any pointers on the file definition will
</pre>
</blockquote>
<pre wrap="">be great).
</pre>
<blockquote type="cite">
<pre wrap="">That said, from what we can tell, the system loads (making sure I am
not misunderstand you here), such as total cooling coil output, does
reflect the changes we make. That said, since I am trying to separate
them out into gains from walls/window, etc, I was looking into the
</pre>
</blockquote>
<pre wrap="">loads side.
</pre>
<blockquote type="cite">
<pre wrap="">I assume there must be some outputs from DOE2 file which eQuest is
reading from which describe what I am looking for.
Any additional help will be awesome.
thanks everyone
- James
At 12:40 PM 10/2/2009, Joe Huang wrote:
</pre>
<blockquote type="cite">
<pre wrap="">James,
There are two sets of loads in DOE-2, in both the LOADS and SYSTEMS
routines. Make sure you're looking at the SYSTEMS loads, not the
LOADS loads.
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd. Suite 108D
Moraga CA 94556
<a class="moz-txt-link-abbreviated" href="mailto:YJHuang@whiteboxtechnologies.com">YJHuang@whiteboxtechnologies.com</a>
</pre>
</blockquote>
</blockquote>
<pre wrap=""><a class="moz-txt-link-rfc2396E" href="mailto:YJHuang@whiteboxtechnologies.com"><mailto:YJHuang@whiteboxtechnologies.com></a>
</pre>
<blockquote type="cite">
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