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<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>I
am having two issues with variable speed pumping and delta T of heating and
cooling loops. The problem is occurring in multiple models. Anybody have any
suggestions?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Two
issues: <o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><span
style='mso-list:Ignore'>1)<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>We
are modeling a chilled water system with a centrifugal chiller. We
specify the delta-T at the loop and zone. When we review the hourly
reports, the delta-T is never maintained at the specified design conditions
regardless of chiller load. The pumps continuously run at lower speeds
(~40% of design capacity) which drives up the delta T at high loads.
We’ve come across this problem in both heating and cooling loops, and in
all models that we’ve looked at. Is this a known issue? Do you have
any suggestions to solve this problem?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><span
style='mso-list:Ignore'>2)<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>A
related issue concerns the energy balance in heating and cooling loops. Looking
at an hourly report of our primary heating or cooling loop, if we calculate the
product of 500* primary supply flow (variable 3) *deltaT (loop return
temperature, variable 22 – loop supply temperature, variable 21) we do
not get the primary loop load (variable 5). We are concerned that all
energy is not being accounted for. How does eQuest perform the
calculations for loop load and gpm? Are there known issues with regard to
the energy balance of heating and cooling loops? <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Thanks<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Justin</span><span
style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:#BB0000'><br>
<br>
</span><o:p></o:p></p>
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