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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hello,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I am doing an ASHRAE 90.1-2007 PRM analysis for a LEED 2009 CS project, credit EAc1. The baseline system is System 7 – VAV with Reheat.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Appendix G has the following requirements for System 7:<o:p></o:p></p><p class=MsoNormal><span style='mso-fareast-language:EN-CA'><img width=521 height=186 id="Picture_x0020_2" src="cid:image001.jpg@01CE3762.36BA8840" alt="cid:image003.jpg@01CE36DF.AC800100"></span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>In keeping with the above requirements, when the temperature is satisfied in any zone, I am supplying 0.4 cfm/ft<sup>2</sup> at 59F (54F + 5F reset). This is causing many zones to be overcooled and, therefore, reheated. The result is that I have a significant amount of simultaneous heating and cooling in my baseline model. Section 6.5.2.1 states that reheating, recooling and simultaneous heating/cooling is not allowed unless the air volume is no greater than 0.4 cfm/ft<sup>2</sup> (or the larger of 0.4 cfm/ft<sup>2</sup>, the ventilation requirement, 30% of max flow, etc.). Therefore, my baseline is allowed to overcool and reheat since it is running at 0.4 cfm/ft<sup>2</sup>.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>My proposed model does not have this problem as it is allowed to go below 0.4 cfm/ft<sup>2</sup> and it is allowed to reset by more than 5F. I am achieving unreasonably high savings as a result of this issue.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>What I find interesting is that G3.1.3.13 has been revised for ASHRAE 90.1-2010 to the following:<o:p></o:p></p><p class=MsoNormal><span style='mso-fareast-language:EN-CA'><img width=528 height=363 id="Picture_x0020_1" src="cid:image002.jpg@01CE3762.36BA8840" alt="cid:image004.jpg@01CE36DF.AC800100"></span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The minimum is no longer an absolute 0.4 cfm/ft<sup>2</sup> but a relative 30% of zone peak air flow. In mild or heating dominated climates 30% of zone peak air flow can be much less than 0.4 cfm/ft<sup>2</sup>.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>By changing the requirement for 90.1-2010 is this an acknowledgement by ASHRAE that the previous requirement could lead to an inefficient baseline model? Am I justified in exploiting it to achieve high savings?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thank you!<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black;mso-fareast-language:EN-CA'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#4D4D4D;mso-fareast-language:EN-CA'>Brian Tysoe </span></b><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#4D4D4D;mso-fareast-language:EN-CA'>M.A.Sc., P.Eng., LEED AP </span><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black;mso-fareast-language:EN-CA'><o:p></o:p></span></p><p class=MsoNormal><i><span style='font-size:9.0pt;font-family:"Arial","sans-serif";color:#4D4D4D;mso-fareast-language:EN-CA'>Associate, National Manager of Energy Modelling Services </span></i><span style='font-size:9.0pt;font-family:"Arial","sans-serif";color:#4D4D4D;mso-fareast-language:EN-CA'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black;mso-fareast-language:EN-CA'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black;mso-fareast-language:EN-CA'><a href="http://www.mcw.com" title="Click here to visit www.mcw.com"><b><i><span style='color:green;text-decoration:none'>MCW Consultants Ltd. </span></i></b></a><o:p></o:p></span></p><p class=MsoNormal><i><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#4D4D4D;mso-fareast-language:EN-CA'>Queen’s Quay Terminal <br>207 Queen’s Quay West, Suite 615 <br>Toronto, ON, Canada M5J 1A7 <br>Phone: (416) 598-2920 ext:519 <br>Fax: (416) 598-5394 </span></i><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black;mso-fareast-language:EN-CA'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black;mso-fareast-language:EN-CA'> <o:p></o:p></span></p><p class=MsoNormal><i><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#4D4D4D;mso-fareast-language:EN-CA'>This e-mail may be privileged and confidential. 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