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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Hi Nicolas,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>This is Nick from the mailing-list discussion you referenced.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I think assuming a constant exiting ground temperature through
the year is one way of doing it – this is the way geothermal loop design
was first introduced to me (before energy modeling had built the level of
momentum it has today). However, recognizing that eQuest is in front of you, I
think you’d agree that to not take advantage of eQuest’s potential to
model ground loop temperature changes through the year (i.e. utilizing the
inputs of loop temperature/ground properties in the wizards) would be
lamentable. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>As with nearly everything in the world of energy modeling, the direct
answer to your question of whether these varying temperatures have a “significant
impact” for your project would truly be “it depends.” In the
case of my last project, the exiting loop temperatures were modeled to vary within
a range that had significant effects on my heatpumps’ operating
efficiencies vs. a constant well temperature (where I had started). I think in
many cases, establishing a ground temperature schedule is worth the effort to model
something that moves towards resembling actual performance and is something I personally
plan to continue doing in future projects.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>How best to do this however remains something up for debate!<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Personally, I feel the method I’ve put forward to estimate
ground temperatures to create a custom lake/well temperature schedule, using
the DX system heatpumps which eQuest can model against the ground/loop
properties defined in the wizards, while not the most accurate way of going
about the task, is the best return I’ve seen so far with regard to
accuracy:time-spent. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>You’ve probably gathered from the mailing list archives:
there’s some honest and worthwhile debate on how to best come up with an
accurate temperature schedule or otherwise account for the realities of varying
ground loop temperature (at least until eQuest gets around to a new version
supporting other ground source system types). Mr. David Reddy responded in
that same linked discussion with an alternative method which is a fundamentally
different approach. He did a good job of stating potential flaws to the method
I’ve described. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Something I have not personally explored, but I believe may likely
the best approach altogether (something I hope to explore for my next GSHX
project), is to use some “true” geothermal loop design software
alongside the Quest model to aid in both initial component sizing and to
examine/import ground/loop temperature changes over time – not just
within a modeled year but over the long-term (say 20 years), allowing the
examination of the necessity for additional or future loop heat rejection
equipment. From the eQuest help files: “</span>Examples of dedicated
ground source heat exchange components sizing programs include: GCHPCalc,
GS2000, GLHEPRO, and GLD (Ground Loop Design).<span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'> ” I’d be very
interested to hear others’ experiences with these and other loop modeling
packages, and how their data may be integrated into our eQuest models. Last I
checked around, I believe I downloaded GS2000 for a test drive as it’s a
free package…<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>To address your other question in a much shorter fashion: When
you say the EIR curve is greyed out, did you check the tab labeled “Performance
Curves” two tabs over from where you took that screengrab?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>~Nick<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><img width=119 height=37 id="Picture_x0020_1"
src="cid:image001.jpg@01CA351B.1F5E8E00" alt="cid:489575314@22072009-0ABB"></span><b><span
style='font-size:11.0pt;font-family:"Stylus BT","sans-serif";color:#2D4D5E'><o:p></o:p></span></b></p>
<p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Stylus BT","sans-serif";
color:#2D4D5E'><o:p> </o:p></span></b></p>
<p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Stylus BT","sans-serif";
color:#2D4D5E'>NICK CATON, E.I.T.</span></b><b><span style='font-family:"Stylus BT","sans-serif";
color:#2D4D5E'><o:p></o:p></span></b></p>
<p class=MsoNormal><span style='font-size:7.5pt;font-family:"Calibri","sans-serif";
color:#CC9900'>PROJECT ENGINEER</span><span style='font-size:7.5pt;color:#CC9900'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";
color:#2D4D5E'>25501 west valley parkway<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";
color:#2D4D5E'>olathe ks 66061<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";
color:#2D4D5E'>direct 913 344.0036<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";
color:#2D4D5E'>fax 913 345.0617<o:p></o:p></span></p>
<p class=MsoNormal><i><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";
color:#2D4D5E'>Check out our new web-site @ </span></i><span style='font-size:
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href="www.smithboucher.com" title="blocked::www.smithboucher.com"><span
style='font-size:10.0pt'>www.smithboucher.com</span></a></span><u><span
style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:blue'> </span></u><span
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</div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Nicolas Mercier
[mailto:nmercier@hilsonmoran.com] <br>
<b>Sent:</b> Monday, September 14, 2009 8:07 AM<br>
<b>To:</b> davidr@madisonengineeringps.com; equest-users@lists.onebuilding.org;
Nick Caton<br>
<b>Cc:</b> Mattia Mariani<br>
<b>Subject:</b> 4-pipe system and ground source heat pump. <o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p>Dear equest users, <o:p></o:p></p>
<p>I am currently modeling a 4-pipe fan coil system connected to a ground
source heat pump. <o:p></o:p></p>
<p>I followed this approach to develop the water-side HVAC within equest <o:p></o:p></p>
<p>1. Create a 'chiller' of the type 'water-to-water heat pump'<br>
2. Create an independent circulation loop of the type 'lake/well'<br>
3. Create a ground loop heat exchanger of the type 'lake/well'<br>
4. Select as the chiller CW loop and GLHX circulation loop the<br>
independent loop you created - they should connect without errors<br>
5. Assign a custom temperature schedule for the lake/well ground loop<br>
in the screen that pops up when you double click the GLHX (read on)<br>
6. Make sure the default head/pump properties for the circulation loop<br>
and GLHX make sense for your system - adjust as necessary. (i.e. if it's
a<br>
closed ground loop, there shouldn't be static head)<o:p></o:p></p>
<p>as explained in this thread "loop to loop heatpump in equest"<o:p></o:p></p>
<p><a
href="http://lists.onebuilding.org/htdig.cgi/equest-users-onebuilding.org/2009-July/001862.html">http://lists.onebuilding.org/htdig.cgi/equest-users-onebuilding.org/2009-July/001862.html</a><o:p></o:p></p>
<p>Instead of using a custom temperature schedule for the lake/well, I am
considering a constant temperature all year around (15°C)<o:p></o:p></p>
<p>Does that assumption has significant impact on the modeling itself ?.<o:p></o:p></p>
<p>Also, by using a loop-to-loop heat pump, I am no able to change the heating
EIR efficiency/curve. See schematic and image attached. <o:p></o:p></p>
<p>Do you have any idea how to change the heating EIR because it is grey out on
my model. <o:p></o:p></p>
<p>Let me know if I am on the right track<o:p></o:p></p>
<p>Thanks, <o:p></o:p></p>
<p>Nicolas Mercier<o:p></o:p></p>
<p>Sustainability Consultant, LEED AP<o:p></o:p></p>
<div>
<p class=MsoNormal> <o:p></o:p></p>
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