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Julien,<br>
<br>
I don't mind at all being quoted or cited, but since I don't read
everything that's posted, just the ones that intrigue me, you might
want to cc me via e-mail to get my attention. It's true that I had
said in an earlier post that I've found DOE-2 models to be "lighter"
than measurements, it was not just by a bit, but by a lot. I didn't
do any serious investigation into the discrepancy, but I attributed
it to the models assuming uniform air conditions within a space,
surface air film coefficients based on smooth planar surfaces, and
uniform distribution of the internal thermal mass within the space.
As scientists or engineers, there's a preference for "getting the
inputs right", i.e., having the furniture-fraction correspond to the
actual amount of furniture in the space, but it may be that either
the algorithm or the inputs need to be tweaked in order to get a
indoor air temperatures closer to what's actually observed.<br>
<br>
Joe<br>
<pre class="moz-signature" cols="90">Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
<a class="moz-txt-link-abbreviated" href="mailto:yjhuang@whiteboxtechnologies.com">yjhuang@whiteboxtechnologies.com</a>
<a class="moz-txt-link-freetext" href="http://weather.whiteboxtechnologies.com">http://weather.whiteboxtechnologies.com</a> for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"
</pre>
<div class="moz-cite-prefix">On 6/18/2015 1:04 AM, Julien Marrec
wrote:<br>
</div>
<blockquote
cite="mid:CAEqKKty8W+Gd5K9aZz0b_sah8_QRQYTYcyePQyg7pMYKCbOiqA@mail.gmail.com"
type="cite">
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<div>
<div>Jeff,<br>
<br>
In E+ there's also an "InternalMass" objec. It is listed
under the group "Thermal Zones and Surfaces". It only asks
for a construction, a zone name, and its surface (m² / ft²):
might be easier.<br>
<br>
From the I/O reference:<br>
<i><b>Internal Mass</b><br>
is used to specify the construction/material parameters
and area of items within the space that are important to
heat transfer calculations but not necessarily important
geometrically. (For example, furniture within the space –
particularly for large spaces).</i><br>
<br>
John,<br>
<br>
Both e+ and equest can have internal mass objects, that you
can add/or customize.<br>
<br>
E+ having no defaults on the subject, it won't take any
internal mass into account unless you tell it to.<br>
<br>
eQuest has by default some internal mass: Floor-weight and
Furniture. For Furniture - default is FURN-WEIGHT = 2 lb/ft²
of floor area - compare that to what you think you have in
your garage and you'll see the difference :))<br>
<br>
I think an even bigger problem is to use external walls
(especially in equest where it's so easy...) defined only by
R-value as opposed to layer-by-layer, thus with no thermal
mass...<br>
<br>
I'm pretty sure as a general rule we tend to underestimate
the overall thermal mass.<br>
On the subject, I remembered Joe Huang (Joe, I hope you
don't mind me quoting you) making a comment about DOE2
making "lighter" models than real anyway so you have to
"boost up the internal mass considerably beyond what's there
to get the floating temperature profiles to match measured
temperatures" (see his post <a moz-do-not-send="true"
href="http://lists.onebuilding.org/htdig.cgi/bldg-sim-onebuilding.org/2015-January/046078.html">here</a>)<br>
<br>
</div>
Best,<br>
</div>
Julien<br>
<div>
<div><br>
<br>
> Le 17 juin 2015 à 20:20, "Eurek, John S NWO" <<a
moz-do-not-send="true"
href="mailto:John.S.Eurek@usace.army.mil">John.S.Eurek@usace.army.mil</a>>
a écrit :<br>
><br>
> Classification: UNCLASSIFIED<br>
> Caveats: NONE<br>
><br>
> General question:<br>
><br>
> Do any energy models take into account the thermal mass
of stuff?<br>
><br>
> Then extreme case I know about is a garage. When my
garage was empty and I turned on the heater it heated up
fairly quickly. When I brought in my truck, tools, shelves,
etc. (a few tons of steel) it took a lot lot longer to get
warm.<br>
><br>
> This is an extreme case, but the same thing would
happen in every type of building on some level.<br>
><br>
> -----Original Message-----<br>
> From: Equest-users [mailto:<a moz-do-not-send="true"
href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a>]
On Behalf Of Jeff Haberl<br>
> Sent: Wednesday, June 17, 2015 10:39 AM<br>
> To: Peter Schonherr; <a moz-do-not-send="true"
href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br>
> Subject: [EXTERNAL] Re: [Equest-users] Thermal mass
effects of interior walls<br>
><br>
> Hello Peter,<br>
><br>
><br>
><br>
> Create layered walls with the materials you intend to
simulate and then set the floor weight = 0 to trigger custom
weighting factors. You may have to fiddle with the interior
convection/radiation coefficient to get a meaningful
“connection” to the room air node.<br>
><br>
><br>
><br>
> Jeff<br>
><br>
><br>
><br>
> 8=! 8=) :=) 8=) ;=) 8=) 8=( 8=) 8=() 8=) 8=|
8=) :=') 8=) 8=?<br>
> Jeff S. Haberl,
Ph.D.,P.E.inactive,FASHRAE,FIBPSA,......<a
moz-do-not-send="true" href="mailto:jhaberl@tamu.edu">jhaberl@tamu.edu</a>
<mailto:........<a moz-do-not-send="true"
href="mailto:jhaberl@tamu.edu">jhaberl@tamu.edu</a>><br>
>
Professor........................................................................Office
Ph: 979-845-6507<br>
> Department of
Architecture............................................Lab
Ph:979-845-6065<br>
> Energy Systems
Laboratory...........................................FAX:
979-862-2457<br>
> Texas A&M
University...................................................77843-3581<br>
> College Station, Texas, USA,
77843..............................URL:<a
moz-do-not-send="true" href="http://www.esl.tamu.edu">www.esl.tamu.edu</a><br>
> 8=/ 8=) :=) 8=) ;=) 8=) 8=() 8=) :=) 8=) 8=!
8=) 8=? 8=) 8=0<br>
><br>
><br>
><br>
> From: Equest-users [mailto:<a moz-do-not-send="true"
href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a>]
On Behalf Of Peter Schonherr<br>
> Sent: Wednesday, June 17, 2015 10:26 AM<br>
> To: <a moz-do-not-send="true"
href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br>
> Subject: [Equest-users] Thermal mass effects of
interior walls<br>
><br>
><br>
><br>
> Hello,<br>
><br>
><br>
><br>
> Is it possible to model the effects of thermal
mass of interior walls? if so, how is that done?<br>
><br>
><br>
><br>
> Peter Schonherr<br>
><br>
><br>
><br>
><br>
> Classification: UNCLASSIFIED<br>
> Caveats: NONE<br>
><br>
><br>
> _______________________________________________<br>
> Equest-users mailing list<br>
> <a moz-do-not-send="true"
href="http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org">http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org</a><br>
> To unsubscribe from this mailing list send a blank
message to <a moz-do-not-send="true"
href="mailto:EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG">EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG</a><br>
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<br>
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