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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>If the condenser and recovery loop are in series, it is probably
done to protect the system from having the condensing loop oversized. I had to
address this concern in the supermarket industry a number of years ago. A
particular supermarket chain purchased the same model of heat recovery for
every store regardless of the size and amount of refrigeration in each store. This
resulted in some smaller stores having an oversized heat recovery system. This
is primarily a concern for part load operation.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>If the refrigerant changes to liquid before it hits the condenser,
the condenser becomes a refrigerant tank. What effectively happens is that the system’s
volume of refrigerant (as liquid phase in the condenser) starves the
evaporators. In the case I spoke of, the maintenance people then added
refrigerant to the system which worked until the system neared design load
again and then the system tripped on high head. This produced an endless cycle
of adding/removing refrigerant until we had the owner resize the heat recovery
loop.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>And, our standard as refrigeration engineers, was to size the
heat recovery system for no more than 50% credit for this very reason. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
bldg-sim-bounces@lists.onebuilding.org
[mailto:bldg-sim-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Aaron.Etzkorn@tac.com<br>
<b>Sent:</b> Friday, October 10, 2008 9:04 AM<br>
<b>To:</b> bldg-sim@lists.onebuilding.org<br>
<b>Subject:</b> [Bldg-sim] Amount of heat recovered for an electric heat
recoverychiller<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>All:</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Does
anyone know why there is a maximum limit of around 50% of the available heat
rejection from the chiller condenser that can be rejected to a heat recovery
loop.</span><o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Can
this be overcome, or is it a default for that chiller type?</span><o:p></o:p></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
style='font-size:8.0pt;font-family:"Verdana","sans-serif"'>Thanks,</span><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><span
style='font-size:8.0pt;font-family:"Verdana","sans-serif"'>Aaron Etzkorn, EIT</span></b><br>
<span style='font-size:8.0pt;font-family:"Verdana","sans-serif";color:black'>Engineer
I<br>
<br>
</span><b><span style='font-size:8.0pt;font-family:"Verdana","sans-serif"'>TAC<br>
</span></b><span style='font-size:8.0pt;font-family:"Verdana","sans-serif"'>16011
College Blvd, Suite 212<br>
Lenexa, KS 66219</span><br>
<br>
<span style='font-size:8.0pt;font-family:"Verdana","sans-serif";color:black'>Direct: +1
(913) 469-0203 <br>
Fax: +1 (913) 469-0206<br>
Mobile: +1 (913) 620-3291<br>
Email: </span><u><span style='font-size:8.0pt;font-family:"Verdana","sans-serif";
color:blue'><a href="mailto:Aaron.Etzkorn@tac.com"
title="mailto:Aaron.Etzkorn@tac.com">Aaron.Etzkorn@tac.com</a><br>
</span></u><span style='font-size:8.0pt;font-family:"Verdana","sans-serif";
color:black'>Web: </span><u><span style='font-size:
8.0pt;font-family:"Verdana","sans-serif";color:blue'><a
href="http://www.tac.com/" title="http://www.tac.com/">www.tac.com</a><br>
<br>
</span></u><span style='font-size:8.0pt;font-family:"Verdana","sans-serif";
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return by email and then delete it.</span> <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
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