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<TITLE>[bldg-sim] GHP in eQuest and predicted vs. actual performance</TITLE>
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<DIV id=idOWAReplyText70889 dir=ltr>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2>I'm also very glad to
know more comparison <FONT face="Times New Roman">between eQUEST predicted
and actual energy performance for GSHP<BR>systems. According to a previous
comparison study and my experience, the GLHE (vertical) model implemented in DOE
2.2 (and DOE 2.1 E) significantly over-predict the swing of loop temperature,
which could in turn result in the under-prediction of the savings from GSHP
systems.</FONT></FONT></DIV>
<DIV dir=ltr><FONT size=2></FONT> </DIV>
<DIV dir=ltr><FONT size=2>In addition, the ground thermal properties and
undisturbed ground temperature (which could be a few degrees higher than the
soil temperature because of the vertical ground thermal heat flux) play an
important role in the GSHP performance. The errors in
these parameters may also be responsible for the
under-prediction.</FONT></DIV>
<DIV dir=ltr><FONT size=2></FONT> </DIV>
<DIV dir=ltr><FONT size=2>Another thing needs to be mentioned is that current
eQUEST doesn't account for the effect of grouting, which could change the loop
temperature significantly.</FONT></DIV>
<DIV dir=ltr><FONT size=2></FONT> </DIV>
<DIV dir=ltr><FONT size=2>Last but not the least, the eQUEST default COP and EER
of the GSHP are far below those of the currently available GSHP units. Higher
COP and EER will make a big difference in the predicted energy
savings.</FONT></DIV>
<DIV dir=ltr><FONT size=2></FONT> </DIV>
<DIV dir=ltr><FONT size=2>This is my experience of using eQUEST for GSHP
simulation. Hope it helps. I am looking forward to other peoples opinion and
experience.</FONT></DIV>
<DIV dir=ltr><FONT size=2></FONT> </DIV>
<DIV dir=ltr><FONT size=2>Have a nice week,</FONT></DIV>
<DIV dir=ltr><FONT size=2></FONT> </DIV>
<DIV dir=ltr><FONT size=2>Xiaobing</FONT></DIV></DIV>
<DIV dir=ltr><BR>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> bldg-sim@gard.com on behalf of Renee J.
Azerbegi<BR><B>Sent:</B> Sun 10/2/2005 11:43 AM<BR><B>To:</B>
bldg-sim@gard.com<BR><B>Subject:</B> [bldg-sim] GHP in eQuest and predicted vs.
actual performance<BR></FONT><BR></DIV>
<DIV>
<P><FONT size=2>Yes, you can model ground source heat pump systems (GSHP). How
accurate the<BR>results are I'm not sure. You have to create a Loop in water
side and then<BR>add a Ground Loop Heat Exchanger. Check the min and max alarm
temperatures<BR>since sometimes these need to be adjusted.<BR><BR>I did model a
small 10,000 sf building a few years ago in eQuest with GSHP<BR>and compared it
to actual data. Predicted was 43 kBtu/sf/yr and actual was<BR>25 kBtu/sf/yr (a
99 Energy Star rating!) My life cycle cost results showed<BR>the indirect/direct
evaporative cooling was better than GSHP (since the<BR>building was in a dry
climate of Colorado), however the owner wanted to go<BR>with the GSHP system.
The owner is very energy conscious so they do turn off<BR>equipment at around 3
PM for this school maintenance building which might be<BR>part of the low energy
usage, however, I wonder if eQuest under-predicts the<BR>savings from GSHP
systems?<BR><BR>GSHPs are all the rage, but I don't think they are
cost-effective if you<BR>have natural gas for heating as your base case. But
then again, with the<BR>rising cost of natural gas, maybe they will be more
affordable. Anyone else<BR>have any experience with predicted versus actual
energy performance for GSHP<BR>systems?<BR><BR>Renee<BR><BR>-----Original
Message-----<BR>From: bldg-sim@gard.com [<A
href="mailto:bldg-sim@gard.com">mailto:bldg-sim@gard.com</A>] On Behalf Of Leela
Kala<BR>Sent: Friday, September 30, 2005 9:17 AM<BR>To:
bldg-sim@gard.com<BR>Subject: [bldg-sim] GHP in eQuest<BR><BR>Hi,<BR>Can I model
GHP in eQuest? If yes, I will appreaciate<BR>if someone can send me teh
details.<BR><BR>thanks<BR><BR>Leela<BR><BR><BR>
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