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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I am having some difficulties regarding ventilation in VAV
systems for a LEED energy model that some of you have probably encountered and
would like your ideas regarding how to handle them. I am using Trane TRACE v.6.1.2.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>1. ASHRAE 62.1-2004 requires some ventilation in storage
rooms – 0 cfm/person (because it is typically unoccupied) and 0.12 cfm/sq
ft (Table 6-1). I have a school with some internal storage rooms (no envelope
exposure). The only internal load is lighting. Even if I have the lights on,
the supply air needed is less than 0.12 cfm/sq ft, so the ventilation fraction
for the room is greater than one. The multiple space equation then causes the
entire VAV system to need 100% outside air. Then the baseline model would need
energy recovery…You see how far from reality this is going?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>One idea I had to deal with it is to manually override the
supply air to some quantity above 0.12 cfm/sq ft instead of using the
calculated supply air flow, but I have a feeling that the LEED evaluator would
not look favorably on that. Perhaps it would be acceptable as long as I did it
the same in both the baseline and the proposed building. What suggestions do
you have for dealing with this?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>2. ASHRAE 90.1-2004 Appendix G requires that the minimum
volume setpoints for VAV reheat boxes to be 0.4 cfm/sq ft for the baseline (G3.1.3.13).
This also causes the same problem as above – 100% outside air for the
system. Of course the minimum volume setpoints for the proposed model would
match the design, so it is only a problem for the baseline. The critical rooms
are not only storage rooms mentioned above, but other spaces where the
ventilation requirement exceeds the load demand, such as restrooms. I have
transfer air set up for each of these spaces. Is there some trick with using
transfer air to make it work out? <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>There were no interpretations for 90.1 that addressed this.
The only related CIR I found from the USGBC was dated 2-2-07 with a ruling on 2-26-07
for a lab which states in part, “Alternately, the project may opt to
model the VAV system as energy neutral and use the design minimum turn down
ratios of the proposed design.” I take this to mean that I could have the
minimum settings in the baseline match the proposed, but I would have to change
the envelope and lighting for each room in the system to match the baseline to
make the system “energy neutral.” We would loose credit for the
lighting savings. There were other CIRs that stated that the 0.4 cfm/sq ft
minimum setting could be disregarded in spaces where pressures needed to be
maintained (laboratories, hospitals, etc.) Any suggestions?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>Sincerely,<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>Keith
Swartz, PE, LEED® AP<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><ns0:PlaceName w:insAuthor="Keith Swartz"
w:insDate="2008-02-11T09:00:00Z" w:endInsAuthor="Keith Swartz"
w:endInsDate="2008-02-11T09:00:00Z"><st1:PlaceName w:st="on">Energy</st1:PlaceName></ns0:PlaceName>
<ns0:PlaceType w:insAuthor="Keith Swartz" w:insDate="2008-02-11T09:00:00Z"
w:endInsAuthor="Keith Swartz" w:endInsDate="2008-02-11T09:00:00Z"><st1:PlaceType
w:st="on">Center</st1:PlaceType></ns0:PlaceType> of <ns0:place
w:insAuthor="Keith Swartz" w:insDate="2008-02-11T09:00:00Z"
w:endInsAuthor="Keith Swartz" w:endInsDate="2008-02-11T09:00:00Z"><ns0:State
w:insAuthor="Keith Swartz" w:insDate="2008-02-11T09:00:00Z"
w:endInsAuthor="Keith Swartz" w:endInsDate="2008-02-11T09:00:00Z"><st1:State
w:st="on"><st1:place w:st="on">Wisconsin</st1:place></st1:State></ns0:State></ns0:place><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
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w:insDate="2008-02-11T09:00:00Z" w:endInsAuthor="Keith Swartz"
w:endInsDate="2008-02-11T09:00:00Z"><ns0:address w:insAuthor="Keith Swartz"
w:insDate="2008-02-11T09:00:00Z" w:endInsAuthor="Keith Swartz"
w:endInsDate="2008-02-11T09:00:00Z"><st1:Street w:st="on"><st1:address w:st="on">455
Science Drive</st1:address></st1:Street></ns0:address></ns0:Street><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><ns0:address w:insAuthor="Keith Swartz"
w:insDate="2008-02-11T09:00:00Z" w:endInsAuthor="Keith Swartz"
w:endInsDate="2008-02-11T09:00:00Z"><ns0:Street w:insAuthor="Keith Swartz"
w:insDate="2008-02-11T09:00:00Z" w:endInsAuthor="Keith Swartz"
w:endInsDate="2008-02-11T09:00:00Z"><st1:address w:st="on"><st1:Street w:st="on">Suite</st1:Street></ns0:Street></st1:address>
200</ns0:address><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><ns0:place w:insAuthor="Keith Swartz"
w:insDate="2008-02-11T09:00:00Z" w:endInsAuthor="Keith Swartz"
w:endInsDate="2008-02-11T09:00:00Z"><ns0:City w:insAuthor="Keith Swartz"
w:insDate="2008-02-11T09:00:00Z" w:endInsAuthor="Keith Swartz"
w:endInsDate="2008-02-11T09:00:00Z">Madison</ns0:City>, <ns0:State
w:insAuthor="Keith Swartz" w:insDate="2008-02-11T09:00:00Z"
w:endInsAuthor="Keith Swartz" w:endInsDate="2008-02-11T09:00:00Z">WI</ns0:State>
<ns0:PostalCode w:insAuthor="Keith Swartz" w:insDate="2008-02-11T09:00:00Z"
w:endInsAuthor="Keith Swartz" w:endInsDate="2008-02-11T09:00:00Z">53711</ns0:PostalCode></ns0:place><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Phone: 608-238-8276 ext. 123<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Fax: 608-238-0523<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><a href="http://www.ecw.org/">www.ecw.org</a><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The Energy Center of Wisconsin is an independent, nonprofit
organization that seeks solutions to energy challenges.</span></font><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'><o:p></o:p></span></font></p>
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