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<TITLE>RE: [bldg-sim] Another DOE-2 question..</TITLE>
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<P><FONT SIZE=2>Jason - My previous question had to do with the apparent small difference in Return Air and Mixed Air Temperature in hourly printout from a DOE-2.1E model. I also asked if the input of Outside Air at the ZONE level translated into the SYSTEM level.</FONT></P>
<P><FONT SIZE=2>I received several kind suggestions to insure I had my OUTSIDE-AIR-CFM set correctly, as well as:</FONT>
<BR><FONT SIZE=2>---------------------------------------------------------------------------------</FONT>
</P>
<P><FONT SIZE=2>No, OA is done as PO being <>0 thus Tmix being Trx(1-PO) + Toa*PO.</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>Is OA-CONTROL fixed? Does SV-A show the system OA fraction as what you expected; if not, you may</FONT>
<BR><FONT SIZE=2>have used the wrong keyword.</FONT>
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<P><FONT SIZE=2>---</FONT>
<BR><FONT SIZE=2>Jeff Hirsch</FONT>
<BR><FONT SIZE=2>James J. Hirsch & Associates</FONT>
<BR><FONT SIZE=2>Building Performance Analysis Software & Consulting</FONT>
<BR><FONT SIZE=2>12185 Presilla Road</FONT>
<BR><FONT SIZE=2>Camarillo, CA 93012-9243 USA</FONT>
<BR><FONT SIZE=2>phone: (805) 553-9000</FONT>
<BR><FONT SIZE=2>fax: (805) 532-2401</FONT>
<BR><FONT SIZE=2>email: Jeff.Hirsch@DOE2.com</FONT>
<BR><FONT SIZE=2>web: <A HREF="http://DOE2.com" TARGET="_blank">http://DOE2.com</A></FONT>
<BR><FONT SIZE=2>-----------------------------------------------------------------------------------</FONT>
<BR><FONT SIZE=2>Graham & Megan [hamnmegs@ozemail.com.au]</FONT>
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<P><FONT SIZE=2>Outside air set at zone level should be fine and takes precedence over any system level outdoor air command. </FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>Have you checked variable #39 (PO) to see if the outdoor air damper is in fact open? If not then have you set outdoor air requirements using OA-CHANGES or CFM/person? if the latter then you need to have people in the space to have outside air delivered - i.e. works like demand controlled ventilation.</FONT></P>
<P><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>Aside from that what you suggest should work. You may want to look at ambient and return air humidity ratio as well so you can see you latent ventilation load ...</FONT></P>
<P><FONT SIZE=2>Graham</FONT>
<BR><FONT SIZE=2>--------------------------------------------------------------------------------------</FONT>
<BR><FONT SIZE=2>(John again)</FONT>
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<P><FONT SIZE=2>As it turned out, I DID have my OUTSIDE-AIR-CFM in ZONE set ridiculously low (BLUSH). When I correct the OSA back to the Design numbers, the T mix and T Return became much further apart. So, indeed, the ZONE level OSA DID translate into the SYSTEM level. And reasonable numbers ensued.</FONT></P>
<P><FONT SIZE=2>Thanks again to ALL who helped me square this away !!!</FONT>
</P>
<P><FONT SIZE=2>John R. Aulbach, PE, CEM</FONT>
<BR><FONT SIZE=2>Project Engineer</FONT>
<BR><FONT SIZE=2>Sempra Energy Solutions</FONT>
<BR><FONT SIZE=2>555 West Fifth Street</FONT>
<BR><FONT SIZE=2>Mail Location 27F3</FONT>
<BR><FONT SIZE=2>Los Angeles, CA 90013</FONT>
<BR><FONT SIZE=2>Tel: (213) 244-8551 Cell (213) 219-4875</FONT>
<BR><FONT SIZE=2> </FONT>
</P>
<P><FONT SIZE=2>"Sempra Energy Solutions is not the same company as SDG&E/ SoCalGas, the Utilities. Sempra Energy Solutions is not regulated by the California Public Utilities Commission, and you do not have to buy Sempra Energy Solutions products or services to continue to receive quality regulated service from the Utilities." </FONT></P>
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