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Metkell,<br>
Typically the sign of Q is used to determine whether it is a
heating load or a cooling load. Cooling loads should cause a rise in
temperature of course so I think that with your equations below
you'd want q to be negative so that dT comes out negative and T2
comes out greater then T1.<br>
<br>
The answer to your second question depends a bit on the heat pump
technology that you are modeling. A single stage heat pump will not
provide a constant supply temperature. Single stage heat pumps have
a constant speed compressor and so essentially run at capacity
whenever they are on. Type927 models such a heat pump. Recently heat
pumps with variable speed compressors have become more common. These
devices often try to maintain a constant supply temperature by
modulating the speed of the compressor.<br>
Kind regards,<br>
David<br>
<br>
<br>
<div class="moz-cite-prefix">On 2/19/2014 06:51, metkell yebiyo
wrote:<br>
</div>
<blockquote
cite="mid:1392814264.85936.YahooMailNeo@web173106.mail.ir2.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff; font-family:times
new roman, new york, times, serif;font-size:10pt">
<pre>Dear TRNSYS Users,</pre>
<pre>I am using a water-water heat pump (Type 927) to simulate an existing installation.
I have the heating and cooling demand profiles of the building, therefore I use an equation with the formula Q=m*Cp*ΔT <span style="font-size: 10pt;">to calculate the returning temperature of the fluid (T2) in the load loop for each time step. </span></pre>
<pre><span style="font-size: 10pt;">Flow rate = 6.8 l/s</span>
</pre>
<pre>Cp = 4.18</pre>
<pre>dT= (Q*3600)/(Flowrate_to_Load*Cp)</pre>
<pre>T1 = Constant</pre>
<pre>T2 = T1-dT</pre>
<pre>Q = heating or cooling load</pre>
<pre>1. when calculating dT how do I differentiate between the heating and cooling data?</pre>
<pre>2.Should the return temperature (T1) from the heat pump be constant or is there another way of calculating the return temperature?</pre>
<pre><pre>For the load loop the only components I use are the heat pump, one equation and a single speed pump.</pre><pre>
</pre><pre>Thank you in advance.</pre><pre>
</pre><pre>Regards,</pre><pre>
<div class="MsoNormal">Metkel Yebiyo BEng (Hons), MSc</div><div class="MsoNormal">CEREB PhD Researcher - Ground Source Heat Pumps </div><div class="MsoNormal">Room T615 </div><div class="MsoNormal">Department of Urban Engineering </div><div class="MsoNormal">Faculty of Engineering, Science and the Built Environment</div><div class="MsoNormal">London South Bank University, </div><div class="MsoNormal">103 Borough Road,</div><div class="MsoNormal">London SE1 0AA</div><div class="MsoNormal">Tel: +44 (0)20 7815 7639</div><div class="MsoNormal">E: <a moz-do-not-send="true" href="mailto:yebiyom@lsbu.ac.uk">yebiyom@lsbu.ac.uk</a><o:p></o:p></div>
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<pre class="moz-signature" cols="72">--
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