<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-size: 13px;color: rgb(0, 0, 0);font-family: arial, sans-serif;">Where you are and what is the design wet-bulb at which you select the 5DegF approach is also important. If you are in San Francisco and select a 5 DegF approach on the design wet-bulb temperature of 65DegF, that cooling tower has a much better evaporative coupling to a cooling selected selected in Miami, FL with a 5 DegF approach to the 80DegtF design wet-bulb. That is because the enthalpic difference between 65DegF and 70 DegF wet bulb is about 4 Btu/lb of dry air, while the enthalpic difference between 80DegF and 85DegF is 5.75 Btu/lb. That means you have to evaporatively cool 30% more air at 65 DegF wet bulb to get a ton of cooling heat rejection, compared with 80 DegF wet-bulb. <div><br></div><div><br><br><blockquote style="padding-left: 5px; margin-left: 0px; border-left: #0000ff 2px solid; font-weight: normal; font-style: normal; text-decoration: none; font-size: 10pt; font-family: arial,sans-serif; color: black;">-----Original Message-----
<br>From: Julien MARREC <julien.marrec@gmail.com>
<br>Sent: Jun 19, 2017 4:07 PM
<br>To: "Peters, Judith M" <judith.peters@daikinapplied.com>
<br>Cc: Danielle Bond <danielle@ecapnet.com>, Dan Nall <dannall@mindspring.com>, "bldg-sim@lists.onebuilding.org" <bldg-sim@lists.onebuilding.org>
<br>Subject: Re: [Bldg-sim] Cooling Tower Approach
<br><br><zzzhtml><zzzhead><zzzmeta http-equiv="content-type" content="text/html; charset=utf-8"></zzzmeta></zzzhead><zzzbody dir="auto"><div>Judy,</div><div><br></div><div>You didn't specify which software you're using, but in general (and for e+ Specifically) you should pay attention to the difference between design input values and the operation conditions.</div><div>In e+ that's the different between what you input in the Cooling tower and the plantloop and sizing objects, versus the setpointManager (setpointmanager:followoutdoorairtemperature set to wetbulb control in particular) you use on the plant outlet to determine the operating conditions at each hour.</div><div><br></div><div>(Excuse any typos or misnamed objects above, going off memory here).</div><div><br></div><div>In reality and as was said by others, if you design a cooling tower for a smaller approach but with the same fan power you end up with an oversized hear exchanger thus allowing lower fan energy across the full year.</div><div><br></div><div>Best,</div><div>Julien</div><div><br>Envoyé de mon iPhone</div><div><br>Le 19 juin 2017 à 18:26, "Peters, Judith M via Bldg-sim" <<a target="_blank" href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a>> a écrit :<br><br></div><blockquote type="cite"><div><zzzmeta http-equiv="Content-Type" content="text/html; charset=utf-8"><zzzmeta name="Generator" content="Microsoft Word 14 (filtered medium)"><style><ZZZ!--
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</o:idmap></o:shapelayout></xml><zzz![endif]--><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Dan and Danielle,<o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thank you for your excellent comments. The results make more sense to me now.<o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thanks again,<o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Judy<o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D">Judy Peters, PE LEED-AP BEMP<o:p></o:p></span></b></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D">Energy Modeling Engineer<o:p></o:p></span></p><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D">Daikin Applied<o:p></o:p></span></b></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D">763.553.5155<o:p></o:p></span></p><p class="MsoNormal"><u><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:blue"><a target="_blank" href="mailto:judith.peters@daikinapplied.com">judith.peters@daikinapplied.com</a></span></u><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D"> | <a target="_blank" href="http://www.daikinapplied.com/">www.DaikinApplied.com</a><o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p><p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Danielle Bond [<a target="_blank" href="mailto:danielle@ecapnet.com">mailto:danielle@ecapnet.com</a>] <br><b>Sent:</b> Monday, June 19, 2017 11:07 AM<br><b>To:</b> Dan Nall<br><b>Cc:</b> Peters, Judith M; <a target="_blank" href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a><br><b>Subject:</b> Re: [Bldg-sim] Cooling Tower Approach<o:p></o:p></span></p><p class="MsoNormal"><o:p> </o:p></p><div><p class="MsoNormal"><span style="font-size:9.5pt">In general, a smaller approach means the cooling tower is more efficiently rejecting heat, i.e. better performance. This overview is pretty good: </span><a target="_blank" href="http://spxcooling.com/pdf/TR-016.pdf"><span style="font-size:9.5pt">http://spxcooling.com/pdf/TR-016.pdf</span></a><o:p></o:p></p><div><p class="MsoNormal"><span style="font-size:9.5pt"><o:p> </o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:9.5pt">Best,<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:9.5pt">Danielle<o:p></o:p></span></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><div><p class="MsoNormal">-- <o:p></o:p></p><div><div><p class="MsoNormal">Danielle Bond, Ph.D.<o:p></o:p></p><div><p class="MsoNormal">Energy Engineer, <span style="font-size:9.5pt">eCap Network</span><o:p></o:p></p></div><div><p class="MsoNormal"><a target="_blank" href="http://www.ecapnet.com/">http://www.ecapnet.com/</a><o:p></o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div></div></div><div><p class="MsoNormal">On Mon, Jun 19, 2017 at 11:50 AM, Dan Nall via Bldg-sim <<a target="_blank" href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a>> wrote:<o:p></o:p></p><div><div><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">If you input a tower with a lower approach but with the same fan power, you would wind up with less annual fan energy consumption, because your fan with the lower approach temperature would hit the minimum condenser water temperature at a higher wet-bulb temperature, allowing the fan to back off more hours of the year. <o:p></o:p></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span class="gmail-"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">-----Original Message----- </span></span><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black"><br><span class="gmail-">From: "Peters, Judith M via Bldg-sim" </span><br><span class="gmail-">Sent: Jun 19, 2017 11:13 AM </span><br><span class="gmail-">To: "<a target="_blank" href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a>" </span><br><span class="gmail-">Subject: [Bldg-sim] Cooling Tower Approach </span></span><span class="gmail-"><o:p></o:p></span></p><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black">I am looking for tips on how to properly compare tower approach temps. Currently, I am comparing a 7 F approach with a 5 F approach. The tower has 4 cells with 44 kW fan energy for each cell and a 10 F range. </span><o:p></o:p></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black"> <o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black">Regardless of control parameters, the program shows less tower energy for a smaller approach and I was expecting the opposite.<o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black"> <o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black">Can anyone shed some light on this issue?<o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black"> <o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black">Thank you!<o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black"> <o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black"> <o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black"> <o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span style="color:#0D0D0D">Judy Peters, PE LEED-AP BEMP</span></b><span style="color:black"><o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#0D0D0D">Energy Modeling Engineer</span><span style="color:black"><o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span style="color:#0D0D0D">Daikin Applied</span></b><span style="color:black"><o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#0D0D0D"><a target="_blank" href="tel:(763)%20553-5155">763.553.5155</a></span><span style="color:black"><o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><u><span style="color:blue"><a target="_blank" href="mailto:judith.peters@daikinapplied.com">judith.peters@daikinapplied.com</a></span></u><span style="color:#0D0D0D"> | <a target="_blank" href="http://www.daikinapplied.com/">www.DaikinApplied.com</a></span><span style="color:black"><o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black"> <o:p></o:p></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:black"> <o:p></o:p></span></p></div></div></div><p class="MsoNormal" style="margin-bottom:12.0pt"><br>_______________________________________________<br>Bldg-sim mailing list<br><a target="_blank" href="http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org">http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org</a><br>To unsubscribe from this mailing list send a blank message to <a target="_blank" href="mailto:BLDG-SIM-UNSUBSCRIBE@ONEBUILDING.ORG">BLDG-SIM-UNSUBSCRIBE@ONEBUILDING.ORG</a><o:p></o:p></p></div><p class="MsoNormal"><br><br clear="all"><o:p></o:p></p><div><p class="MsoNormal"><o:p> </o:p></p></div><div><div><div><p class="MsoNormal"><o:p> </o:p></p></div></div></div></div></div></div></zzz![endif]--></zzz!--[if></zzz![endif]--></zzz!--[if></zzzmeta></zzzmeta></div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>Bldg-sim mailing list</span><br><span><a target="_blank" href="http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org">http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org</a></span><br><span>To unsubscribe from this mailing list send a blank message to <a target="_blank" href="mailto:BLDG-SIM-UNSUBSCRIBE@ONEBUILDING.ORG">BLDG-SIM-UNSUBSCRIBE@ONEBUILDING.ORG</a></span><br></div></blockquote></zzzbody></zzzhtml></bldg-sim@lists.onebuilding.org></dannall@mindspring.com></danielle@ecapnet.com></judith.peters@daikinapplied.com></julien.marrec@gmail.com></blockquote></div></div></body></html>