<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:10pt"><div>Jim:<br><br>What do you mean by condenser relief?<br><br>Paul Diglio<br></div><div style="font-family: times new roman,new york,times,serif; font-size: 10pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> James Hansen <JHANSEN@ghtltd.com><br><b><span style="font-weight: bold;">To:</span></b> equest-users@lists.onebuilding.org<br><b><span style="font-weight: bold;">Sent:</span></b> Mon, March 14, 2011 11:23:04 AM<br><b><span style="font-weight: bold;">Subject:</span></b> [Equest-users] which chiller curve(s) to modify?<br></font><br>
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--></style><div class="WordSection1"><p class="MsoNormal">I know there was a recent discussion about chiller curves, but I can’t seem to access <a rel="nofollow" target="_blank" href="http://www.gard.com">www.gard.com</a> right now, so I thought would send out this email since I don’t remember it being discussed.</p><p class="MsoNormal"> </p><p class="MsoNormal">I have two different curves for a standard water-cooled 200-ton screw chiller:</p><p class="MsoNormal"> </p><p class="MsoListParagraph" style=""><span style="">1)<span style="font: 7pt "Times New Roman";"> </span></span>EIR based on PLR, but with AHRI condenser relief</p><p class="MsoListParagraph" style=""><span style="">2)<span style="font: 7pt "Times New Roman";"> </span></span>EIR based on PLR, with NO condenser relief, and varying return chilled water temperature (from design at 100% to only about
a 2 degree delta between supply and return at the 20% load range)</p><p class="MsoNormal"> </p><p class="MsoNormal">Which curves should I modify with custom curves? I am so confused.</p><p class="MsoNormal"> </p><p class="MsoNormal">The f(PLR) curve says it should be the EIR vs PLR with no condenser water reset. That one’s the easy one. I already set that one up, and it’s about $1000 cheaper a year than the default curve, so I know it’s at least in the right range.</p><p class="MsoNormal"> </p><p class="MsoNormal">But the f(t evap leaving, t cond entering) says it’s a quadratic curve, but since there are two variables, shouldn’t it be bi-quadratic like the Cooling Capacity curve as a function of entering CW and leaving CHW?</p><p class="MsoNormal"> </p><p class="MsoNormal">When you all get chiller PLR curves with condenser relief, which curve(s) do you modify and to what extent?</p><p
class="MsoNormal"> </p><p class="MsoNormal">Thanks!</p><p class="MsoNormal"> </p><p class="MsoNormal"><b><span style="font-family: "sans-serif"; color: teal;">GHT Limited<br></span></b><b><span style="font-family: "sans-serif";"><span style="color: black;">James Hansen</span></span></b><b><span style="color: black;">, PE, LEED AP</span></b></p><p class="MsoNormal"><b><span style="font-size: 10pt; font-family: "sans-serif"; color: black;">Senior Associate</span></b><b><span style="color: black;"></span></b></p><p class="MsoNormal"><span style="font-size: 7.5pt; font-family: "sans-serif";"><span style="color: black;">1010 N. Glebe Rd, Suite 200</span></span></p><p class="MsoNormal"><span style="font-size: 7.5pt; font-family: "sans-serif";"><span style="color: black;">Arlington</span><span style="color: black;">, </span><span style="color: black;">VA</span><span style="color: black;">
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