Hi Nick,<br><br>How do you think this standard from ASHRAE 90.1 G3.1.3.13 <span style="background-color: rgb(255, 255, 102);">VAV Minimum Flow Setpoints (Systems 5 and 7). Minimum volume setpoints for VAV reheat boxes shall be 0.4 cfm/ft2 of floor area served or the minimum ventilation rate, whichever is larger.</span><br>
<br>In my opinion, it means, if we set "Minimum Design Flow is 0.5 cfm/ft2", the VAV minimum flow should be set 80% (we assume the minimum ventilation rate is smaller than VAV minimum flow.), Or I am wrong?<br><br>
Thank you very much.<br><br>Best,<br>Xiaoyang<br><br><br><div class="gmail_quote">On Fri, Mar 11, 2011 at 5:18 PM, Nick Caton <span dir="ltr"><<a href="mailto:ncaton@smithboucher.com">ncaton@smithboucher.com</a>></span> wrote:<br>
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<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">Hi there Xiaoyang,</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">VAV min flows can be set both in wizards and in detailed edit
modes. See following screenshots.</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">The “standard” depends on the HVAC design, and
specifically how ventilation air is being distributed. There’s a
range of CFM’s that the factory will set as a minimum terminal unit at
depending on the size, but it may well be zero if you are distributing
ventilation air via DOAS in certain ways. I’d suggest asking your
HVAC designer directly what the minimum is for each unit (it’s probably
scheduled), and use that info to either come up with an average for each zone
or to set the minimum for each zone separately.</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">Here’s the wizard…</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"><img src="" width="720" height="511"></span><span style="font-size: 11pt; color: rgb(31, 73, 125);"></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">… and in detailed, double click on a space served by a VAV
system, under the Airside HVAC tab, to find the following window. In this
case, the minimum flow is set to 30% (0.30):</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"><img src="" width="732" height="626"></span><span style="font-size: 11pt; color: rgb(31, 73, 125);"></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">~Nick</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"><img src="" alt="cid:489575314@22072009-0ABB" width="119" height="37"></span><b><span style="font-size: 11pt; color: rgb(45, 77, 94);"></span></b></p>
<p class="MsoNormal"><b><span style="font-size: 11pt; color: rgb(45, 77, 94);"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size: 11pt; color: rgb(45, 77, 94);">NICK CATON, E.I.T.</span></b><b><span style="color: rgb(45, 77, 94);"></span></b></p>
<p class="MsoNormal"><span style="font-size: 7.5pt; color: rgb(204, 153, 0);">PROJECT ENGINEER</span></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(45, 77, 94);">Smith & Boucher Engineers</span><span style="font-size: 7.5pt; color: rgb(204, 153, 0);"></span></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(45, 77, 94);">25501 west valley parkway</span></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(45, 77, 94);">olathe ks 66061</span></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(45, 77, 94);">direct <a href="tel:913%20344.0036" target="_blank">913 344.0036</a></span></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(45, 77, 94);">fax <a href="tel:913%20345.0617" target="_blank">913 345.0617</a></span></p>
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<p class="MsoNormal"><b><span style="font-size: 10pt;">From:</span></b><span style="font-size: 10pt;"> <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>xiaoyang
shi<br>
<b>Sent:</b> Friday, March 11, 2011 2:35 PM<br>
<b>To:</b> <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b>Subject:</b> [Equest-users] VAV minimum flow</span></p>
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<p class="MsoNormal">Hi folks,<br>
<br>
Do you know how to set the <span style="background: none repeat scroll 0% 0% rgb(255, 255, 102);">"VAV minimum
flow" (percentage) </span>at the "HVAC zones: temperatures and Air
Flows" panel? eQUEST default number is 40%. Is there any standard?<br>
<br>
Thank you.<br>
<br>
</p>
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