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<DIV><FONT face=Arial size=2>The problem being asked about arises due to the
different uses of the</FONT></DIV>
<DIV>
<DIV><FONT face=Arial size=2>alternative methods available in eQUEST freeware
</FONT><FONT face=Arial size=2>(a MS Windows implementation</FONT></DIV>
<DIV><FONT face=Arial size=2>of </FONT><FONT face=Arial size=2>DOE-2.2) to
describe both the </FONT><FONT face=Arial size=2>minimum outside air (OA) damper
position</FONT></DIV>
<DIV><FONT face=Arial size=2>as well as the minimum flow </FONT><FONT face=Arial
size=2>fraction setting of the VAV boxes in each zone. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The min-flow-ratio for a <FONT face=Arial
size=2>VAVS system </FONT>(DOE-2 keyword found on the SYSTEM</FONT></DIV>
<DIV><FONT face=Arial size=2>properties sheet, </FONT><FONT face=Arial
size=2>fan tab, flow parameters sub tab in the eQUEST details mode</FONT></DIV>
<DIV><FONT face=Arial size=2>interface) is the minimum VAV box flow fraction for
all boxes supplied by the "parent"</FONT></DIV>
<DIV><FONT face=Arial size=2>air handler for the zone;</FONT><FONT face=Arial
size=2> this value can be specified for each individual box or for</FONT></DIV>
<DIV><FONT face=Arial size=2>a system and thus "inherited" by all zone boxes
supplied by the system. If not given</FONT></DIV>
<DIV><FONT face=Arial size=2>a value (min flow fraction </FONT><FONT face=Arial
size=2>control on the mentioned subtab) defaults </FONT><FONT face=Arial
size=2>to the larger of</FONT></DIV>
<DIV><FONT face=Arial size=2>the minimum ventilation </FONT><FONT face=Arial
size=2>requirement, the flow required to satisfy </FONT><FONT face=Arial
size=2>the zone peak heating</FONT></DIV>
<DIV><FONT face=Arial size=2>load heating, or other </FONT><FONT face=Arial
size=2>available minimum flow specifications (</FONT><FONT face=Arial
size=2>such as cfm/sqft, etc.)</FONT></DIV>
<DIV><FONT face=Arial size=2>In dual duct or dual fan dual duct VAV systems the
boxes have many more controls</FONT></DIV>
<DIV><FONT face=Arial size=2>including separate heat/cool and overall box
minimum flow; consult the DOE-2.2</FONT></DIV>
<DIV><FONT face=Arial size=2>dictionary (<A
href="http://doe2.com/download/DOE-22/DOE22Vol2-Dictionary.pdf">http://doe2.com/download/DOE-22/DOE22Vol2-Dictionary.pdf</A>)
or eQUEST</FONT></DIV>
<DIV><FONT face=Arial size=2>online help (although this is less complete and not
as up to date) for more detail.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>When the outside air fraction
is set to </FONT><FONT face=Arial size=2>1 this is interpreted as
a minimum ventilation</FONT></DIV>
<DIV><FONT face=Arial size=2>requirement and thus is found to be the
maximum value of the various defaults for</FONT></DIV>
<DIV><FONT face=Arial size=2>the VAV box minimum flow value. If the
</FONT><FONT face=Arial size=2>minimum cfm fraction is specified (on
the</FONT></DIV>
<DIV><FONT face=Arial size=2>subtab mentioned above) rather than letting it
default, the specified value </FONT><FONT face=Arial size=2>will be
used</FONT></DIV>
<DIV><FONT face=Arial size=2>for all ZONE VAV boxes in that SYSTEM.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>For example, on the system properties sheet the fan
tab and flow </FONT><FONT face=Arial size=2>parameters sub tab,</FONT></DIV>
<DIV><FONT face=Arial size=2>you can place a value for min flow ratio, and that
will become the min flow for all VAV</FONT></DIV>
<DIV><FONT face=Arial size=2>boxes on the SV-A report </FONT><FONT
face=Arial size=2> ...</FONT></DIV>
<DIV><FONT face=Arial size=2>the hourly OA fraction will then be governed by the
fraction of design vs. hourly values</FONT></DIV>
<DIV><FONT face=Arial size=2>choice on the system properties sheet outdoor air
tab, outside air and economizer subtab.</FONT></DIV>
<DIV><FONT face=Arial size=2>If (on the same properties sheet fans /flow subtab)
the min flow cfm/ft2 control is set instead,</FONT></DIV>
<DIV><FONT face=Arial size=2>you would still </FONT><FONT face=Arial size=2>get
OA=1 all hours because this is one of the values compared to the
ventilation</FONT></DIV>
<DIV><FONT face=Arial size=2>to choose the maximum needed minimum box flow
setting. (I know the online help is a bit</FONT></DIV>
<DIV><FONT face=Arial size=2>dated and poorly </FONT><FONT face=Arial
size=2>worded ... we are trying to get funding to improve it ... but this
information</FONT></DIV>
<DIV><FONT face=Arial size=2>is all there, </FONT><FONT face=Arial size=2>just
requires a bit of a careful read.)</FONT></DIV></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>By the way, the SV-A, and other DOE-2 reports are
now easily examined: the eQUEST</FONT></DIV>
<DIV><FONT face=Arial size=2>version 3.51 freeware pre-release <FONT face=Arial
size=2>posted on </FONT><FONT face=Arial size=2><A
href="http://DOE2.com/eQUEST/">http://DOE2.com/eQUEST/</A> has a new
simulation</FONT></FONT></DIV>
<DIV><FONT face=Arial size=2><FONT face=Arial size=2>results details viewer that
</FONT><FONT face=Arial size=2>allows viewing of multiple .sim files with direct
access to reports through</FONT></FONT></DIV>
<DIV><FONT face=Arial size=2><FONT face=Arial size=2>an index. This viewer can
be used to view .sim results file produced by any version of
DOE-2.2</FONT></FONT></DIV>
<DIV><FONT face=Arial size=2><FONT face=Arial size=2>freeware,
</FONT></FONT><FONT face=Arial><FONT size=2>but is best used with versions 43
and beyond due to fully uniform report headers (in
those</FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2>versions) that the </FONT></FONT><FONT
face=Arial><FONT size=2>viewer uses to locate reports and error messages within
a .sim file.</FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2></FONT></FONT> </DIV>
<DIV><FONT face=Arial><FONT size=2>Version 3.51 of eQUEST has many other
improvements to both the simulation engine and interface</FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2>including: a 5-10 times speed increase of
project open and compliance simulation times, an first
version</FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2>of a BDL </FONT></FONT><FONT face=Arial><FONT
size=2>error manager to view an error tree to assist in navigation to and fixing
of model errors, and new DOE-2</FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2>simulation features that can be found
documented (with other post version 40 additions) in Volume
6</FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2>of the DOE-2.2 documentation
at</FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2> <A
href="http://doe2.com/download/DOE-22/DOE22Vol6-NewFeatures.pdf">http://doe2.com/download/DOE-22/DOE22Vol6-NewFeatures.pdf</A><FONT></DIV>
<DIV></FONT></FONT></FONT><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>This is a pre-release to allow extensive public
comment and review (followed by our fixing issues</FONT></DIV>
<DIV><FONT face=Arial size=2>identified) prior to the retirement of older
versions; this version has been in wide use for some time</FONT></DIV>
<DIV><FONT face=Arial size=2>now (starting with version 3.50) and appears to be
close to "ready for prime time."</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Happy simulating ...</FONT></DIV>
<DIV><BR>---<BR>Jeff Hirsch<BR>James J. Hirsch & Associates<BR>Building
Performance Analysis Software & Consulting<BR>12185 Presilla
Road<BR>Camarillo, CA 93012-9243 USA<BR>phone: (805)
553-9000<BR>fax: (805) 532-2401<BR>email: <A
href="mailto:Jeff.Hirsch@DOE2.com">Jeff.Hirsch@DOE2.com</A><BR>web: <A
href="http://DOE2.com">http://DOE2.com</A></DIV>
<DIV> </DIV>
<DIV> </DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=keirh@bluestoneenergy.com
href="mailto:keirh@bluestoneenergy.com">Keir Howell</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=BLDG-SIM@gard.com
href="mailto:BLDG-SIM@gard.com">BLDG-SIM@gard.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, August 30, 2004 8:25
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [BLDG-SIM] Modeling 100% OA VAV
systems in eQuest</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2></FONT><FONT face=Arial size=2>Hello. Whenever I
try to model a VAV system with 100% OA in eQuest, I end up with a constant
volume system. It seems to be multiplying the Minimum OA Ratio (which I have
set at 1.00) by the design air flow, rather than the hourly air flow, even
though I have set the Minimum OA Method to "Fraction of Hourly Flow". As far
as I know, I have not set any other variables (such as zonal settings) that
might override the system settings. Please help. Thanks,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Keir Howell<BR>Bluestone Energy Services,
Inc.<BR>phone: 781-356-8865<BR>fax:
781-356-8864</FONT></DIV><PRE>
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