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<DIV><SPAN class=640081916-04022009><FONT face=Arial size=2>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.</FONT></SPAN></DIV>
<DIV><SPAN class=640081916-04022009><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=640081916-04022009><FONT face=Arial size=2>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.</FONT></SPAN></DIV>
<DIV><SPAN class=640081916-04022009><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=640081916-04022009><FONT face=Arial size=2>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. </FONT></SPAN></DIV>
<DIV><SPAN class=640081916-04022009><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=640081916-04022009><FONT face=Arial size=2>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. </FONT></SPAN></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV><FONT
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">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
style="COLOR: #808080; TEXT-DECORATION: none"
href="http://www.hargis.biz/">www.hargis.biz</A> <BR><BR><SPAN
style="COLOR: gray"><B>d | </B>206.859.5391</SPAN> <BR><SPAN
style="COLOR: gray"><B>o | </B>206.448.3376 </SPAN><BR><SPAN
style="COLOR: gray"><B> f | </B>206.448.4450</SPAN> <BR></FONT>
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