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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:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>My experience has been the same as James – the smaller units typically have more of a problem, particularly RTUs less than 10 tons. The refrigerant charge is high compared to the maximum allowable to get a total Refrigerant Impact per Ton <100.<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'>Also, I just ran into this on a project as well – there are “supercharged” chillers on the market that also have high charge-per-ton numbers.<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'>See Page 210 of the LEED-BDC reference guide for a table showing the maximum refrigerant charges for typical refrigerants. For RTUs, 15-year life, you have to be less than 1.98 lbs/ton and the last I remember only Trane had a unit at that low of a charge and still met ASHRAE 90.1 minimum efficiencies.<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:7.5pt;font-family:"Verdana","sans-serif";color:#1F497D'>Jeremy R. Poling, PE, LEED AP+BDC</span></b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><br><br></span><span style='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><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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"'> bldg-sim-bounces@lists.onebuilding.org [mailto:bldg-sim-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Cheney<br><b>Sent:</b> Monday, January 31, 2011 12:40 PM<br><b>To:</b> Eurek, John S NWO<br><b>Cc:</b> bldg-sim@lists.onebuilding.org<br><b>Subject:</b> Re: [Bldg-sim] R-410a & EA credit 4 (UNCLASSIFIED)<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Hi Eurek, <o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>The answer to your question is VERY LIKELY. <o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>Why? <o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>* Since R-410a will have 0 ODP and relatively small GWP (1890). Eventually the equation is decided by only LCGWP, since LCODPx10^5 will be 0. <o:p></o:p></p></div><div><p class=MsoNormal>* My personal feeling is that Rc (Refrigerant charge) is critical in your case. The range is from 0.5 to 5 lbs of refrigerant per ton. The smaller the better. <o:p></o:p></p></div><div><p class=MsoNormal>* Considering multi types of equipments, as long as your averaged LCGWP is less than 100, you will be safe. <o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>As suggested by James, you will have to run the calculation to be sure. <o:p></o:p></p></div><p class=MsoNormal><br>-- <o:p></o:p></p><div><p class=MsoNormal><span style='font-family:"Comic Sans MS"'>Regards, </span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Comic Sans MS"'>Cheney</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Comic Sans MS"'>LinkedIN @ </span><a href="http://ca.linkedin.com/pub/yu-cheney-chen/27/637/72b" target="_blank"><span style='font-family:"Comic Sans MS"'>http://ca.linkedin.com/pub/yu-cheney-chen/27/637/72b</span></a><span style='font-family:"Comic Sans MS"'> </span><o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p></div></body></html>