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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi All, <o:p></o:p></p><p class=MsoNormal>I’m modeling a system with DCV set to “DCV-RETURN-SENSOR.” The help file says: “The program calculates the OA minimum requirement and sets the minimum damper position hourly based upon the sum of the ZONE requirements. Each zone OA requirement is calculated based upon the hourly maximum of either OA-CFM/PER (times the NUMBER-OF-PEOPLE adjusted by the hourly PEOPLE-SCHEDULE) or a minimum OA ventilation rate.” <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>However, when I look at the hourly report for the zone, “Hourly zone OA CFM requirement for DCV calculation (cfm)” (Var 100), the CFM does not increase for high occupancy hours. My hand calculations show that when I multiply the OA-CFM/PER by the hourly occupancy, it should exceed the minimum OA ventilation rate for the zone (which I specified using OA-FLOW/AREA.)<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have set the zone minimum flow ratios to “DCV-RESET-UP/DOWN” and the zone minimum flow is increasing according to the occupancy. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Why is the zone OA CFM requirement not increasing with occupancy? Any thoughts are appreciated.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks very much.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Kind regards,<o:p></o:p></p><p class=MsoNormal>Molly<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-family:"Times New Roman","serif";color:#28AAE1'>Molly Curtz</span></b><b><span style='font-family:"Times New Roman","serif";color:#28AAE1'><o:p></o:p></span></b></p><p class=MsoNormal style='text-align:justify'><span style='font-size:10.0pt;font-family:"Times New Roman","serif";color:#595959'>Mechanical Engineer<o:p></o:p></span></p><p class=MsoNormal style='text-align:justify;text-indent:.5in'><span style='font-size:10.0pt;font-family:"Times New Roman","serif";color:#595959'><o:p> </o:p></span></p><p class=MsoNormal style='text-align:justify'><b><span style='font-family:"Times New Roman","serif";color:#595959'>Arup<o:p></o:p></span></b></p><p class=MsoNormal style='text-align:justify'><span style='font-size:10.0pt;font-family:"Times New Roman","serif";color:#595959'>403 Columbia Street Suite 220 Seattle WA 98104<o:p></o:p></span></p><p class=MsoNormal style='text-align:justify'><b><span style='font-size:10.0pt;font-family:"Times New Roman","serif";color:#595959'>t</span></b><span style='font-size:10.0pt;font-family:"Times New Roman","serif";color:#595959'> +1 206 749 9674 <b>d</b> +1 206 493 2234 <o:p></o:p></span></p><p class=MsoNormal style='text-align:justify'><b><span style='font-size:10.0pt;font-family:"Times New Roman","serif";color:#595959'>f</span></b><span style='font-size:10.0pt;font-family:"Times New Roman","serif";color:#595959'> +1 206 749 0665 <b><o:p></o:p></b></span></p><p class=MsoNormal style='text-align:justify'><span style='font-size:10.0pt;font-family:"Times New Roman","serif";color:#595959'>www.arup.com<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div><font face="monospace">____________________________________________________________<br>
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