<html><body bgcolor="#FFFFFF"><div>I think what you are trying to model is a heat</div><div>pump chiller. These machines are pretty cool & </div><div>the economics work when you have strong</div><div>simultaneous heating and cooling loads</div><div>year round, like large hospitals, large universities, etc.</div><div><br></div><div>I have worked on two projects that involved</div><div>the use of heat pump chillers. We used eQuest </div><div>to estimate building loads, but not to model the chiller.</div><div> </div><div>My advice would be to take the 8760 hourly</div><div>cooling and heating loop loads from </div><div>eQuest to a spreadsheet and finish the</div><div>analysis in Excel. </div><div><br></div><div>The eQuest program can do a lot, but I'm </div><div>pretty sure the eQuest program cannot</div><div>model how a heat <span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373); ">pump chiller is operated, </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">at least how they are operated on our </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">projects.</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);"><br></span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">We had the HPC piped into the plant to</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">be in series with the return chilled water.</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">In this manner, the HPC would precool the</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">return chilled water. The control point for the </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">HPC is actually the hot water side. The HPC </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">is controlled to maintain leaving hot water </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">temperature setpoint at 140 to 155 degrees, depending </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">on summer/winter, hot water reset, etc.</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">So the HPC is controlled to meet the heating </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">load, we get whatever cooling we get, and </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">the main chillers provide the remainder of </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">the cooling, if required. The HPC was not </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">piped into a cooling tower loop. In </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">retrospect we found that a plate and frame heat</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">exchanger could be a good idea for</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">when the heating load dropped below the </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">HPC minimum heating output. This allows </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">the HPC to be kept online longer when </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">heating load is dropping, though at some</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">point it makes sense to shut the HPC down.</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);"><br></span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">Bottom line: These HPC's are very tricky</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">and I couldn't figure out how to model them</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">in eQuest, so I did the analysis in Excel.</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);"><br></span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">I hope this is helpful.</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);"><br></span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">Regards, </span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);"><br></span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">James Hess, PE</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">TME, Inc.</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);">Little Rock, AR</span></div><div><span class="Apple-style-span" style="-webkit-composition-fill-color: rgba(175, 192, 227, 0.231373); -webkit-composition-frame-color: rgba(77, 128, 180, 0.231373);"> </span></div><div><br><div>Sent from James' iPod</div></div><div><br>On Mar 9, 2009, at 6:16 PM, "Molly Curtz" <<a href="mailto:molly.curtz@arup.com">molly.curtz@arup.com</a>> wrote:<br><br></div><div></div><blockquote type="cite"><div>
<div><span class="145173522-09032009"><font face="Arial" size="2">Hi
All,</font></span></div>
<div><span class="145173522-09032009"><font face="Arial" size="2"></font></span> </div>
<div><span class="145173522-09032009"><font face="Arial" size="2">Along the same lines
as Tony Kriel's post earlier today, I am also having trouble setting up a
heat recovery chiller in eQuest.</font></span></div>
<div><span class="145173522-09032009"><font face="Arial" size="2"></font></span> </div>
<div><span class="145173522-09032009"><font face="Arial" size="2">Specifically, I am
looking for advice on how to control the chiller. <span class="145173522-09032009"><font face="Arial" size="2">I am using the ELEC-HTREC
chiller type.</font></span> I would like to operate the chiller when
there are simultaneous hot and chilled water loads, up until the point
where either the hot water loop load is satisfied, or the chiller is
operating at maximum capacity. In other words, I do not want to reject any heat
to the condenser water loop, which is required to be attached to the
ELEC-HTREC chiller (in the actual design there is no CW loop to use!) I only
want to operate the heat recovery chiller only when all heat can be rejected to
the hot water loop. Is there a way to control the chiller operation based
on the hot water Loop conditions?</font></span></div>
<div><span class="145173522-09032009"><font face="Arial" size="2"></font></span> </div>
<div><span class="145173522-09032009"></span><font face="Arial"><font size="2">A<span class="145173522-09032009">ny</span><span class="145173522-09032009"> ideas on
how to do this with the ELEC-HTREC chiller? </span><span class="145173522-09032009">Is there another chiller type that can be controlled in
this way?</span></font></font></div>
<div><span class="145173522-09032009"><font face="Arial" size="2"></font></span> </div>
<div><span class="145173522-09032009"><font face="Arial" size="2">Thanks in advance to
anyone who has ideas on this.</font></span></div>
<div><span class="145173522-09032009"><font face="Arial" size="2"></font></span> </div>
<div><span class="145173522-09032009"><font face="Arial" size="2">Kind
regards,</font></span></div>
<div> </div>
<div align="left"><font face="Arial" size="2">Molly Curtz, P.E.</font></div>
<div align="left"><font face="Arial" size="2">Mechanical Engineer</font></div>
<div align="left"><font face="Arial" size="2"></font> </div>
<div align="left"><font face="Arial" size="2">Arup</font></div>
<div align="left"><font face="Arial" size="2">403 Columbia St., Suite 220</font></div>
<div align="left"><font face="Arial" size="2">Seattle, WA 98104</font></div>
<div align="left"><font face="Arial" size="2"><font face="Arial" size="2"><span style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">
<div align="left">direct: 206 493 2234</div>
</span></font></font><div align="left"><font face="Arial" size="2"><font face="Arial" size="2"><span style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"></span><font face="Arial" size="2"><span style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">tel: 206 749
9674 ext. 25534</span></font></font></font></div></div>
<div align="left"><span style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">fax: 206 749
0665</span></div>
<div align="left"><span style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"><a href="mailto:molly.curtz@arup.com">molly.curtz@arup.com</a></span></div>
<div align="left"><font face="Arial" size="2"><a href="http://www.arup.com/"><a href="http://www.arup.com">www.arup.com</a></a></font></div>
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