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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:12.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'>Anyone understand how condenser flow gets assigned for the FREE-COOLING chiller type?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'>Is the operating head of the FREECOOLING chiller over-ridden to force the flow rate and delta-T to match the chilled flow rate and delta T?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'>My building has 3200 gpm condenser water pumps with 10 deg F delta T, approx. 1200 tons rejection during normal operation. (2000 gpm chilled water pumps at 15 deg F delta T.)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'>One of these CW pump is used to provide water for free cooling via a shell-and-tube HX at a reduced delta T (6.25) at the same rough gpm (3200). The chiller is smaller than the main building chillers. (800 tons – chilled water side is designed for lower delta T 10 deg F at same flow rate 200 gpm in this case.)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'>However, no matter my inputs, the hourly flow on the condenser side is 2000 gpm, which exactly matches the flow rate and delta T of the chilled water side.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'>I would expect my specified constant-speed pump to operate at the operating point given by the component pressure drops to yield the design flow rate. However, the head on the condenser side appears over-ridden high to decrease flow to match the chiller side.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'>Any experience or ideas here?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'>Thanks,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'><o:p> </o:p></span></p><p class=MsoNormal style='line-height:150%;text-autospace:none'><b><span style='font-size:9.0pt;line-height:150%;font-family:"Verdana","sans-serif";color:gray'>Aaron Dahlstrom , PE, LEED® AP</span></b><o:p></o:p></p><p class=MsoNormal style='line-height:150%;text-autospace:none'><b><span style='font-family:"AvantGarde Bk BT","sans-serif";color:#17365D'>In P</span></b><b><span style='font-family:"AvantGarde Bk BT","sans-serif";color:#619428'>o</span></b><b><span style='font-family:"AvantGarde Bk BT","sans-serif";color:#17365D'>sse</span></b><span style='font-size:9.0pt;line-height:150%;font-family:"Verdana","sans-serif";color:gray'> – </span><span style='font-size:8.0pt;line-height:150%;font-family:"Verdana","sans-serif";color:gray'>A subsidiary of</span><span style='font-size:9.0pt;line-height:150%;font-family:"Verdana","sans-serif";color:gray'> </span><b><span style='font-size:9.0pt;line-height:150%;font-family:"Verdana","sans-serif";color:#CC0000'>AKF</span></b><span style='font-size:9.0pt;line-height:150%;font-family:"Verdana","sans-serif";color:gray'>| 1500 Walnut Street, Suite 1414, Philadelphia, PA 19102 </span><o:p></o:p></p><p class=MsoNormal style='line-height:150%;text-autospace:none'><span style='font-size:9.0pt;line-height:150%;font-family:"Verdana","sans-serif";color:gray'>d: 215-282-6753| m: 267-507-5470| In Posse: 215-282-6800| AKF: 215-735-7290</span><o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:9.0pt;font-family:"Verdana","sans-serif";color:gray'>e: ADahlstrom@in-posse.com | in posse web: <a href="http://www.in-posse.com/"><span style='color:blue'>www.in-posse.com</span></a> | akf web: <a href="http://www.akfgroup.com/"><span style='color:blue'>www.akfgroup.com</span></a></span><o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:9.0pt;font-family:"Verdana","sans-serif";color:gray'> </span><o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:9.0pt;font-family:"Verdana","sans-serif";color:gray'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Times New Roman","serif";color:gray'> </span><o:p></o:p></p></div><br clear=all> This e-mail may contain information that is confidential, privileged or otherwise protected from disclosure. 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