Hi Etta,<br><br>I found the discussion below in the DOE2 help manual. I would be happy to look at your input if you want to send it to us/me. I couldn't do it until the end of the day but would be willing to.<br><br>Carol<br>
<br>
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<div id="d2h_breadcrumbs" class="d2h_breadcrumbs"><a class="d2h_breadcrumbsNormal" href="volume2rdictionaryrefrigerationsystems.htm">Volume 2r: Dictionary - <font style="background-color: rgb(49, 106, 197);" color="#ffffff">Refrigeration
Systems</font></a><span class="d2h_breadcrumbsLinkSeparator"> > </span><a class="d2h_breadcrumbsNormal" href="refrigerationequipment.htm"><font style="background-color: rgb(49, 106, 197);" color="#ffffff">Refrigeration</font>
Equipment</a></div>
<h2>REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEM</font></h2>
<p class="MsoBodyText"> </p>
<p class="MsoBodyText">This command is the foundation upon which you build a <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigeration system</font>.
DOE-2 defines a <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigeration system</font> to be a closed set of components
(circuits, loads, compressors, condensers, etc.) that share a common <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font>. The <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> is closed because
the <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> in
the <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> can flow
to any of the components in the <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font>, but cannot flow to any components outside the <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> (Figure ??). The
common point in each <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> is the liquid receiver tank immediately downstream
of the condensers. From here, one or more liquid circuits deliver <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> to various
loads. The loads evaporate the <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font>, and suction circuits pass the <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> on to one or
more suction groups (compressor racks). Each suction group has one or more
compressors. The compressors discharge into one or more discharge circuits,
which pass the <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> on to one or more condensers. The condensers
discharge liquid <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> into the liquid receiver.</p>
<p class="MsoBodyText">The REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEM</font> command is similar to the CIRCULATION-LOOP command
in that condensers attach to this component, and are controlled by this
component. However, compressors do not attach directly to the REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEM</font>. This is because a
given REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEM</font>
may have multiple suction groups, each operating at a different suction
temperature, serving a different set of loads, but discharging into the same
condenser. In addition, different compressors may discharge into different
discharge circuits, some of which may be controlled for heat reclaim, and others
not. For this reason, suction-group/compressor assemblies are defined separately
from the REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEM</font>.</p>
<p class="MsoBodyText">You may define more than one REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEM</font>. The only caveat
is that multiple <font style="background-color: rgb(49, 106, 197);" color="#ffffff">systems</font> cannot be cross-connected so that <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> leaves one
<font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> and enters
the other. In other words, <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> leaving the liquid receiver of one <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> must return to the
same receiver. <font style="background-color: rgb(49, 106, 197);" color="#ffffff">Systems</font> can be cross-connected in the sense that <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> from one
<font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> can act on
the <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> of
another <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> via
a heat-exchanger. For example, a subcooler for a low-temperature <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> can be fed with
<font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> from a
medium-temperature <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font>, as long as the subcooler utilizes a heat-exchanger
to keep the <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> streams completely separate (Figure ??). The
same is true of desuperheaters, and <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font>-to-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> condensers.</p>
<p class="MsoBodyText">The program checks to see if a load, such as a
REFG-FIXTURE, is cross-connected between two REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEMs</font>. Such
cross-connections will cause the program to abort.</p>
<p class="MsoBodyText">A REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEM</font> can be quite complex, and REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEMS</font> can be intertied
in manners which allow even greater complexity. For example, because a
REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEM</font> may
have multiple suction groups operating at different temperatures, a single <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> can serve both low
and medium-temperature loads. In addition, suction groups can be staged so that
the compressors of a lower-temperature load discharge into a higher-temperature
suction group. When multiple REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEMS</font> use <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerants</font> of different types, it is possible to cascade
the load of a lower-temperature <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> into a higher-temperature <font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> via a <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font>-to-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> condenser.
Examples are given that illustrate these concepts as well as others.</p>
<p class="MsoBodyText">A condenser attaches to a REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEM</font> from the CONDENSER
command. The program allows a <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigeration system</font> to have more than one condenser.</p>
<p class="MsoBodyText">While a REFG-<font style="background-color: rgb(49, 106, 197);" color="#ffffff">SYSTEM</font> normally expects there to be a condenser to reject
heat, you do not have to specify a condenser. In this case, the liquid and
discharge circuits will always be at the hourly condensing temperature setpoint,
the high-temperature energy in the discharge <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigerant</font> will simply
disappear without the expenditure of any condenser energy. This feature can be
useful if you are in the process of constructing a <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigeration system</font>, and
would prefer to specify a condenser after you know more about the design <font style="background-color: rgb(49, 106, 197);" color="#ffffff">refrigeration</font> loads and
<font style="background-color: rgb(49, 106, 197);" color="#ffffff">system</font> operating
characteristics. </p>
<hr noshade size="1"><br></div><br><div class="gmail_quote">On Thu, Oct 28, 2010 at 8:46 AM, Etta Grover-Silva <span dir="ltr"><<a href="mailto:etgrsi@gmail.com">etgrsi@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div>Hey,</div>
<div> </div>
<div>I'm using the refrigeration mode of EQuest to model a meat packing/processing/storage facility. The entire building is basically a walk in cooler with smaller rooms that are colder depending on the type of storage they need it for. The primary Refrig system is external condenser with multiple evaporators within the building set at different set points for different rooms. I modeled this as a building shell with no Air Side HVAC, combined a few condensers and evaporators due to similiar capacities and used Refrigeration fixtures. Was this the right approach? Is the above defined Refrig system similiar to a closed loop condenser to evaporator system?</div>
<div> </div>
<div>Thanks!</div>
<div> </div><font color="#888888">
<div>Etta</div>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Carol Gardner PE<br>
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