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<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=140355322-04022009>Interesting David. We have been discussing how to deal
with the same issue with the Lake/Well loop and heat exchanger always providing
the default ground temperture as well. </SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=140355322-04022009></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=140355322-04022009>When I review the line diagrams for the Loop-to-Loop HP
it appears that it is moving heat from one loop to the other. However, what we
are doing is using a large HP to supply the hot water / cold water to the AHUs
inside the building. From the line diagrams for the Loop-to-Loop HP system it
doesn't appear that this is what that system provides. Am I missing
something?</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=140355322-04022009></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=140355322-04022009>Thank you all for your input.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=140355322-04022009></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=140355322-04022009>Tim</SPAN></FONT></DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> David Reddy [mailto:davejreddy@yahoo.com]
<BR><B>Sent:</B> Wednesday, February 04, 2009 2:12 PM<BR><B>To:</B> 'Karen
Walkerman'; Tim Dion<BR><B>Cc:</B>
equest-users@lists.onebuilding.org<BR><B>Subject:</B> RE: [Equest-users]
Simultaneous Heating/Cooling<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV class=Section1>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'">If
the chiller you are using is the “well-water-to-water HP” type
(CHILLER:HEAT-PUMP), I have successfully been able to run a simulation
with this chiller connected to a CHW loop. However, it was only connected
to a loop with a process chilled water load, and not connected to
coils.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'">The
loop-to-loop HP (CHILLER:LOOP-TO-LOOP-HP), which I believe Karen is referring
to, is intended to be attached to both a HW and CHW circulation loops. As
I understand the DOE-2 help, there is an important difference between these
chillers in that the LOOP-TO-LOOP-HP chiller allows for exchange of heat between
the HW and CHW circulation loops, where as the HEAT-PUMP chiller only moves heat
to-and-from the CW loop (LAKE/WELL type). You can connect multiple
HEAT-PUMP or LOOP-TO-LOOP chillers to a single LAKE/WELL loop and heat
exchanger, so you could potentially have one chiller supply your HW and one
chiller supply CHW by adjusting the controls of the 2-PIPE loop. Having
them connected to the same CW loop, the total CW load should be equal to the sum
of the energy pulled out by the chiller in heating, the energy put in by the
chiller in cooling, and the loop pump heat (plus loop thermal losses if
simulated). However, this is somewhat irrelevant because no matter what
the CW loop return temperature is, the LAKE/WELL loop and heat exchanger will
always provide the scheduled supply temperature (or by default, the hourly
ground temperature in the weather file).<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'">To
get around this, we have developed an approach that takes the building loads
from the LAKE/WELL loop and applies them to a DOE-2 well-field model, and in
turn, takes the resulting well-field temperatures for use in the building hourly
simulation. It requires post-processing and some iteration, but I think
this type of approach could be as good as we can do with the existing
tool.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'">Any
other approaches out there?</SPAN><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><B><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Tahoma','sans-serif'">David
Reddy<o:p></o:p></SPAN></B></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Tahoma','sans-serif'">Madison
Engineering, PS<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Tahoma','sans-serif'">444
NE Ravenna Blvd, Suite 406<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Tahoma','sans-serif'">Seattle,
WA 98115<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Tahoma','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
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<P class=MsoNormal><B><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">From:</SPAN></B><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">
equest-users-bounces@lists.onebuilding.org
[mailto:equest-users-bounces@lists.onebuilding.org] <B>On Behalf Of </B>Karen
Walkerman<BR><B>Sent:</B> Wednesday, February 04, 2009 8:58 AM<BR><B>To:</B> Tim
Dion<BR><B>Cc:</B> equest-users@lists.onebuilding.org<BR><B>Subject:</B> Re:
[Equest-users] Simultaneous Heating/Cooling<o:p></o:p></SPAN></P></DIV>
<P class=MsoNormal><o:p> </o:p></P>
<P class=MsoNormal style="MARGIN-BOTTOM: 12pt">Why are you using a separate
lake/well loop and heat pump for the chilled water loop? You should be
able to have the same piece of machinery attached to both a chilled water loop
and a hot water loop. This way heat is transferred from one loop to the
other when there are simultaneous loads. The ground loop is only used when
there is net heating or cooling needed.<BR><BR>My beef with this system is that
you can only use a loop type of lake/well using a constant condenser water
temperature. This is usually not the case with ground loops, unless you
are circulating water from an underground
reservoir!<BR><BR>--<BR>Karen<BR><BR><o:p></o:p></P>
<DIV>
<P class=MsoNormal>On Wed, Feb 4, 2009 at 11:38 AM, Tim Dion <<A
href="mailto:TimD@hargis.biz">TimD@hargis.biz</A>> wrote:<o:p></o:p></P>
<DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">I'm modeling a ground
loop heat exchanger to provide condenser water to a large water-to-water heat
pump which will be capable of providing simultaneous heating and chilled water
to AHU coils in the building. The Water-to-water Heat Pump being designed around
is similar to that manufactured by Multistack, Heat-Harvester, Climacool,
etc.</SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">I've successfully
created a 2-pipe water loop with a water-to-water heat pump that gets its'
condenser water from a ground loop heat exchanger (lake/well). When assigned to
Fan Coils in the building this system appears to work just fine. However, no
simultaneous heating/cooling capability.</SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">So, I've now added a
chilled water loop with a second water-to-water heat pump that gets its'
condenser water from a seperate ground loop heat exchanger. I then assigned the
cooling coils to the chilled water loop and the heating coils to the 2-pipe
water loop. Trouble is I get the error that reads, "the chilled water loop has
no load". If I manage to get this error to go away then my zones have 5,000 +
hours of unmet heating loads. </SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">I've been searching
the archives and I see that this has come up several times but with no real
solution other than "it should be able to be done". I'm posting the question
again in hopes that someone who has successfully modeled this system can point
the rest of us in the right direction. This type of system is coming up more and
more (I have 4 projects considering them now) and as we strive toward greater
building efficiency we are going to HAVE to be able to successfully model these
system types. </SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">Tim Dion, LEED® AP
<BR>Mechanical<BR><B><SPAN style="COLOR: navy">HARGIS ENGINEERS</SPAN></B>
<BR>600 Stewart Street <BR>Suite 1000 <BR>Seattle, WA 98101 <BR><A
href="http://www.hargis.biz/" target=_blank><SPAN
style="COLOR: gray; TEXT-DECORATION: none">www.hargis.biz</SPAN></A>
<BR><BR><B><SPAN style="COLOR: gray">d | </SPAN></B><SPAN
style="COLOR: gray">206.859.5391</SPAN> <BR><B><SPAN
style="COLOR: gray">o | </SPAN></B><SPAN
style="COLOR: gray">206.448.3376 </SPAN><BR><B><SPAN
style="COLOR: gray"> f | </SPAN></B><SPAN
style="COLOR: gray">206.448.4450</SPAN> </SPAN><o:p></o:p></P>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV></DIV>
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