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<p>Muhammad,</p>
<p> The compressor power (P_compressor) and the heat pump capacity
(q_evaporator) are specified as model parameters at a rated inlet
condition. The rated inlet condition is a particular combination
of inlet air and inlet water temperatures. <br>
</p>
<p> The actual power and capacity are computed from the rated
(parameters) values times a multiplier (from the external file).
The external file basically says how the heat pump power and
capacity are affected by differences between the actual inlet air
and water temperatures and the rated inlet air and water
temperature. <br>
</p>
<p> For instance, if you look at the third line of the Type941
cooling performance data file, you should see something like:</p>
<p>0.943 0.753 !Fraction
capacity and power at T_air = 15.6 deg. C and T_water_in
= 12</p>
<p>this means that when the air inlet temperature is 15.6C and the
water inlet temperature is 12C then the heat pump will have 94.3%
of its rated capacity and will consume 75.3% of its rated power.</p>
<p>So, to answer your question more directly, q_evaporator and
p_compressor are known because you specified them as parameters
and then they were modified according to the external data file.
With those two values, q_condenser can be computed.</p>
<p>I hope that clarifies,</p>
<p> kind regards,</p>
<p> David</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 03/27/2020 09:17, Muhammad Zeeshan
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAOVVR-c+L2gOuq+wY73yuTixhqqcenHnkR36FVATFx0nkXgv=w@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="auto">Thanks a lot David. Would you please elaborate a
bit more about the compressor power how it would be calculated?
<div dir="auto">External files contains fractions of compressor
power e.g. 0.8,0.9 etc. Where as in manual equations are
quoted as: q_condensor = q_evporator + p_compressor </div>
<div dir="auto">Here, both q_condensor and p_compressor are
unknown</div>
<div dir="auto">How q_condensor and p_compressor will be
calculated. </div>
<div dir="auto"><br>
</div>
<div dir="auto">Thanks</div>
<div dir="auto"><br>
</div>
<div dir="auto">Regards,</div>
<div dir="auto">Muhammad Zeeshan </div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri, Mar 27, 2020, 18:45
David BRADLEY <<a href="mailto:d.bradley@tess-inc.com"
target="_blank" rel="noreferrer" moz-do-not-send="true">d.bradley@tess-inc.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<p>Muhammad,</p>
<p> Please refer to the Type941 documentation. It explains
how the external files and the parameters relate to each
other to compute the overall capacity and power
consumption of the heat pump. <br>
</p>
<p> The evaporator does not really need to be designed more
than to choose a machine with an appropriate rated
capacity. Traditionally that might mean adding a safety
factor to the peak cooling load (10% is often used) and
then selecting a machine that will meet that capacity.
Also bear in mind that Type941 models a single speed (ie
single capacity) heat pump that is either on or off.
Depending on how variable the load in your building it,
you might want to meet that load with multiple smaller
heat pumps rather than one big one.</p>
<p>kind regards,</p>
<p> David</p>
<p><br>
</p>
<div>On 03/27/2020 08:02, Muhammad Zeeshan via TRNSYS-users
wrote:<br>
</div>
<blockquote type="cite">
<div dir="auto">Hello Everyone,
<div dir="auto"> </div>
<div dir="auto"> I am working
on cooling a building with type 41(air to water source
heat pump). The cooling load of the building is 25
tons. I want to know</div>
<div dir="auto"><br>
</div>
<div dir="auto">1)- how the compressor power will be
calculated? as the external files of type 941 contains
fractions of compressor power which shows no link to
the equations provided in manual. How to link the
external file with the provided equations?</div>
<div dir="auto"><br>
</div>
<div dir="auto">2)-As the cooling load of the building
is 25 tons, how to design the evaporator for this
building load?</div>
<div dir="auto"><br>
</div>
<div dir="auto">Your help in this regard will be highly
appreciated.</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto">Regards,</div>
<div dir="auto">Muhammad Zeeshan</div>
</div>
<br>
<fieldset></fieldset>
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<pre cols="72">--
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
3 North Pinckney Street - suite 202
Madison, WI 53703 USA
P:+1.608.274.2577
F:+1.608.278.1475
<a href="mailto:d.bradley@tess-inc.com" rel="noreferrer noreferrer" target="_blank" moz-do-not-send="true">d.bradley@tess-inc.com</a>
<a href="http://www.tess-inc.com" rel="noreferrer noreferrer" target="_blank" moz-do-not-send="true">http://www.tess-inc.com</a>
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<pre class="moz-signature" cols="72">--
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
3 North Pinckney Street - suite 202
Madison, WI 53703 USA
P:+1.608.274.2577
F:+1.608.278.1475
<a class="moz-txt-link-abbreviated" href="mailto:d.bradley@tess-inc.com">d.bradley@tess-inc.com</a>
<a class="moz-txt-link-freetext" href="http://www.tess-inc.com">http://www.tess-inc.com</a>
<a class="moz-txt-link-freetext" href="http://www.trnsys.com">http://www.trnsys.com</a></pre>
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