Ooops. Didn't hit reply all.<br><br><div class="gmail_quote">---------- Forwarded message ----------<br>From: <b class="gmail_sendername">Carol Gardner</b> <span dir="ltr"><<a href="mailto:cmg750@gmail.com">cmg750@gmail.com</a>></span><br>
Date: Tue, Nov 16, 2010 at 9:45 AM<br>Subject: Re: [Equest-users] system and zone airflow issue<br>To: Brian Fountain <<a href="mailto:bfountain@greensim.com">bfountain@greensim.com</a>><br><br><br>Hi Brian,<br><br>
I don't have time to research this thoroughly but in general for modeling I would stick to specifying the airflow at the system level. It is important to remember that eQUEST is an energy analysis tool, not a mechanical design tool. If you were doing design I, and your client, would expect to see the VAV box cfms down on the drawings. For energy analysis, I think it's overkill and, as you have found out, you can run up against weird things. The other reason? It adds to the time you are using to do the energy model without getting you anything more (anyone disagree?). I did find one item out of the manuals that may shed light on what to look at if you want to understand what you ran up against. I'll paste it below. Let me know if you figure it out.<br>
<br>Best,<br><br>Carol<br><br><p style="margin-left: 36pt;"><span style="font-family: 'Tms Rmn','serif';">1.
</span>SUPPLY FLOW<br>is the calculated or user-specified supply flow for each
zone. Only if you have specified a value for the ASSIGNED-FLOW keyword in the
ZONE command will the value here correspond to your input. The ZONE keywords
AIR-CHANGES/HR and FLOW/AREA will be accepted by SYSTEMS only if they are
consistent with the user-supplied HEATING-CAPACITY and COOLING-CAPACITY and are
equivalent to a flow larger than that of the exhaust from or the ventilation to
the zone. The ALTITUDE FACTOR will be applied.</p><br><br><div class="gmail_quote"><div class="im">On Tue, Nov 16, 2010 at 8:18 AM, Brian Fountain <span dir="ltr"><<a href="mailto:bfountain@greensim.com" target="_blank">bfountain@greensim.com</a>></span> wrote:<br>
</div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div class="im">
<div bgcolor="#ffffff" text="#000000">
<font size="-1"><font face="Calibri">I recall that there was an
issue with entering both system and zone level airflow values in
eQUEST but a search through the archive did not retrieve what I
was looking for. Perhaps someone can jog my memory. In a
review of a model where both system and zone level airflows were
entered for a VAV system, and where zone level values total up <i>less
than </i>the system value entered, we find that deleting the
system level airflow increased the overall fan energy. I find
this hard to explain.<br>
<br>
<br>
</font></font><br>
</div>
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<br></blockquote></div><font color="#888888"><br><br clear="all"><br>-- <br>Carol Gardner PE<br>
<div></div>
</font></div><br><br clear="all"><br>-- <br>Carol Gardner PE<br>
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