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Fred,<br>
Heating coils are pretty easy because you don't have to worry about
condensation. With cooling coils, if memory serves, you can't quite use
the same effectiveness concept because there is both sensible and
latent cooling going on. Typically what you have to do is to adjust the
bypass fraction at the coil's rated conditions in order to tune the
model to a particular coil's performance. The bypass fraction method
essentially assumes that some of the air comes out of the coil
saturated at the coil water temperature and some of the air bypasses
the coil entirely and remixes downstream.<br>
Best,<br>
David<br>
<br>
Fred Betz wrote:
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<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">Sorry
David, my wording was very
poor. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">What I
was trying to get at is
that the approach temperatures appear too small.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">I have
22C air entering the coil
and 29C air leaving the coil. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">I have
32C water entering the
coil and 25C water leaving the coil. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">That is a
delta T of just 3C, or
5.4F between the air entering and the water leaving. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">It should
be about 7-10F based
on project experience. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">This
might be splitting hairs,
but with 500,000 CFM of air flow, 1 degree means thousands of dollars.
Therefore,
every item gets scrutinized. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">Also, I
was hoping there was a
way to set the effectiveness on the cooling coil like I was able to on
the
heating coil. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">Fred<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<div>
<table class="MsoNormalTable" style="width: 355.5pt;" border="0"
cellpadding="0" width="474">
<tbody>
<tr>
<td style="padding: 0.75pt; width: 125.25pt;" valign="top"
width="167">
<p class="MsoNormal" style=""><b><span
style="font-size: 10pt; color: rgb(102, 0, 0); text-transform: uppercase;">Fred
Betz</span></b><b><span style="font-size: 9pt; color: rgb(51, 51, 51);">
</span></b><span style="font-size: 9pt; color: rgb(51, 51, 51);">PhD.,
LEED AP <br>
</span><span
style="font-size: 10pt; color: rgb(51, 51, 51); text-transform: uppercase;">Sustainable
Systems Analyst</span><span
style="font-size: 9pt; color: rgb(51, 51, 51);"><o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt; width: 7.5pt;" valign="top"
width="10">
<p class="MsoNormal"><span
style="font-size: 9pt; color: rgb(51, 51, 51);"> <o:p></o:p></span></p>
</td>
<td style="padding: 0.75pt; width: 212.25pt;" valign="top"
width="283">
<p class="MsoNormal" style=""><b><span
style="font-size: 9pt; color: rgb(102, 0, 0);">AEI</span></b><span
style="font-size: 9pt; color: rgb(51, 51, 51);"> | AFFILIATED
ENGINEERS, INC. <br>
5802 Research Park Blvd. | Madison, WI 53719<br>
<br>
</span><span style="font-size: 9pt; color: rgb(102, 0, 0);">P:
608.236.1175 | F: 608.238.2614</span><span
style="font-size: 9pt; color: rgb(51, 51, 51);"> <br>
</span><span style="font-size: 9pt; color: rgb(102, 0, 0);"><a
moz-do-not-send="true" href="mailto:fbetz@aeieng.com"><span
style="color: rgb(102, 0, 0); text-decoration: none;">fbetz@aeieng.com</span></a>
| </span><b><span style="font-size: 9pt; color: rgb(102, 0, 0);"><a
moz-do-not-send="true" href="http://www.aeieng.com/"><span
style="color: rgb(102, 0, 0); text-decoration: none;">www.aeieng.com</span></a></span></b><span
style="font-size: 9pt; color: rgb(51, 51, 51);"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<div>
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style="border-style: solid none none; border-color: rgb(181, 196, 223) -moz-use-text-color -moz-use-text-color; border-width: 1pt medium medium; padding: 3pt 0in 0in;">
<p class="MsoNormal"><b><span
style="font-size: 10pt; font-family: "Tahoma","sans-serif"; color: windowtext;">From:</span></b><span
style="font-size: 10pt; font-family: "Tahoma","sans-serif"; color: windowtext;">
David Bradley
[<a class="moz-txt-link-freetext" href="mailto:bradley@tess-inc.com">mailto:bradley@tess-inc.com</a>] <br>
<b>Sent:</b> Monday, March 29, 2010 4:18 PM<br>
<b>To:</b> Fred Betz<br>
<b>Cc:</b> <a class="moz-txt-link-abbreviated" href="mailto:trnsys-users@cae.wisc.edu">trnsys-users@cae.wisc.edu</a><br>
<b>Subject:</b> Re: [TRNSYS-users] Heating Coil: Type 670-1 bug<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Fred,<br>
I think you might be confusing efficiency and effectiveness.
Effectiveness is actual energy transfer divided by maximum
theoretically
possible energy transfer. The air and water side heat transfers need to
be
equal or else there is an energy imbalance across the coil.<br>
Best,<br>
David<br>
<br>
<br>
Fred Betz wrote: <o:p></o:p></p>
<p class="MsoNormal">All,<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">There appears to be a bug in the Type 670-1
heating coil. <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">I set the effectiveness of the coil to 0.70, but
the air and
water side heat transfer rates are approximately equal. <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Anyone have a fix?<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Fred<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<table class="MsoNormalTable" style="width: 355.5pt;" border="0"
cellpadding="0" width="474">
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<td style="padding: 0.75pt; width: 125.25pt;" valign="top"
width="167">
<p class="MsoNormal"><b><span
style="font-size: 10pt; color: rgb(102, 0, 0); text-transform: uppercase;">Fred
Betz</span></b><b><span style="font-size: 9pt; color: rgb(51, 51, 51);">
</span></b><span style="font-size: 9pt; color: rgb(51, 51, 51);">PhD.,
LEED AP <br>
</span><span
style="font-size: 10pt; color: rgb(51, 51, 51); text-transform: uppercase;">Sustainable
Systems Analyst</span><o:p></o:p></p>
</td>
<td style="padding: 0.75pt; width: 7.5pt;" valign="top"
width="10">
<p class="MsoNormal"><span
style="font-size: 9pt; color: rgb(51, 51, 51);"> </span><o:p></o:p></p>
</td>
<td style="padding: 0.75pt; width: 212.25pt;" valign="top"
width="283">
<p class="MsoNormal"><b><span
style="font-size: 9pt; color: rgb(102, 0, 0);">AEI</span></b><span
style="font-size: 9pt; color: rgb(51, 51, 51);"> | AFFILIATED
ENGINEERS, INC. <br>
5802 Research Park Blvd. | Madison, WI 53719<br>
<br>
</span><span style="font-size: 9pt; color: rgb(102, 0, 0);">P:
608.236.1175 | F: 608.238.2614</span><span
style="font-size: 9pt; color: rgb(51, 51, 51);"> <br>
</span><span style="font-size: 9pt; color: rgb(102, 0, 0);"><a
moz-do-not-send="true" href="mailto:fbetz@aeieng.com"><span
style="color: rgb(102, 0, 0); text-decoration: none;">fbetz@aeieng.com</span></a>
| <b><a moz-do-not-send="true" href="http://www.aeieng.com/"><span
style="color: rgb(102, 0, 0); text-decoration: none;">www.aeieng.com</span></a></b></span><span
style="font-size: 9pt; color: rgb(51, 51, 51);"> </span><o:p></o:p></p>
</td>
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</table>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<pre><o:p> </o:p></pre>
<pre style="text-align: center;">
<hr align="center" size="4" width="90%">
</pre>
<pre><o:p> </o:p></pre>
<pre>_______________________________________________<o:p></o:p></pre>
<pre>TRNSYS-users mailing list<o:p></o:p></pre>
<pre><a moz-do-not-send="true" href="mailto:TRNSYS-users@cae.wisc.edu">TRNSYS-users@cae.wisc.edu</a><o:p></o:p></pre>
<pre><a moz-do-not-send="true"
href="https://www-old.cae.wisc.edu/mailman/listinfo/trnsys-users">https://www-old.cae.wisc.edu/mailman/listinfo/trnsys-users</a><o:p></o:p></pre>
<pre> <o:p></o:p></pre>
<p class="MsoNormal"><span
style="font-size: 12pt; font-family: "Times New Roman","serif";"><br>
<br>
<o:p></o:p></span></p>
<pre>-- <o:p></o:p></pre>
<pre>***********************************************************************<o:p></o:p></pre>
<pre>Thermal Energy System Specialists (TESS), LLC <o:p></o:p></pre>
<pre>David BRADLEY 22 N. Carroll Street - Suite 370 <o:p></o:p></pre>
<pre>Partner Madison, WI 53703 <o:p></o:p></pre>
<pre> USA<o:p></o:p></pre>
<pre>P: +1.608.274.2577 <o:p></o:p></pre>
<pre>F: +1.608.278.1475<o:p></o:p></pre>
<pre>E-mail: <a moz-do-not-send="true"
href="mailto:bradley@tess-inc.com">bradley@tess-inc.com</a> <o:p></o:p></pre>
<pre>Web Pages: <a moz-do-not-send="true"
href="http://www.tess-inc.com">http://www.tess-inc.com</a> and <a
moz-do-not-send="true" href="http://www.trnsys.com">http://www.trnsys.com</a><o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>***********************************************************************<o:p></o:p></pre>
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
***********************************************************************
Thermal Energy System Specialists (TESS), LLC
David BRADLEY 22 N. Carroll Street - Suite 370
Partner Madison, WI 53703
USA
P: +1.608.274.2577
F: +1.608.278.1475
E-mail: <a class="moz-txt-link-abbreviated" href="mailto:bradley@tess-inc.com">bradley@tess-inc.com</a>
Web Pages: <a class="moz-txt-link-freetext" href="http://www.tess-inc.com">http://www.tess-inc.com</a> and <a class="moz-txt-link-freetext" href="http://www.trnsys.com">http://www.trnsys.com</a>
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