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Damien,<br>
In my experience, there are relatively few heat pumps available on
the market that can do what you are trying to do. Most heat pumps
have a fairly fixed capacity (some have multiple stages) so that
they have an easier time maintaining a fixed temperature rise than
they do in maintaining a fixed temperature outlet. There is at least
one notable exception to this; an air-to-water heat pump that has a
variable speed compressor that allows it to modulate and maintain a
target outlet temperature. <br>
<br>
Type927 is a temperature level control device meaning that it is
looking for inlet water conditions on both sides and for a control
signal. If you have obtained your heating loads from some other
software tool, I would recommend that you read them into TRNSYS
using Type9 and impose them on a water stream using Type682 from the
TESS Loads and Structures library. I would then place a thermostat
sensing water return temperature in the loop and I would use its
output to turn on the loop pump and the Type927 heat pump. You will
not get a constant supply temperature of course but in reality, a
single stage (or even multi stage) heat pump can't really give you a
constant supply temperature; it can only give you a supply
temperature that hovers around a set point. <br>
<br>
If you are using Type56 to generate your building's heating
demand, I would take it out of energy rate control (ie turn OFF the
automatic heating and cooling types in TRNBuild), and allow the zone
temperatures to float. I would then use a thermostat watching the
zone air temperature and some kind of delivery device (a fan coil,
radiant floors, etc.) to deliver the hot water from the Type927 to
the zone.<br>
<br>
Kind regards,<br>
david<br>
<br>
<br>
On 6/6/2012 12:20, Damien Casetta wrote:
<blockquote
cite="mid:CA+b-pK5xyb7k19Qy-x4a2uFB_4U3kTrP94qs=G4O26Urwy=K2w@mail.gmail.com"
type="cite">Hi,
<div><br>
</div>
<div>I am trying to handle this problem by controlling the
temperature. Let me remind you that I want to control the heat
load of an heat pump in heating mode. </div>
<div><br>
</div>
<div>Here is how I am trying to proceed : </div>
<div><br>
</div>
<div>- I control the temperature exiting the heat pump</div>
<div>- I fix a temperature set point (with an aquastat - heating
mode) at 50 C. </div>
<div>- I vary the supply temperature (entering the heat pump)
according to the heating demand. </div>
<div><br>
</div>
<div>The heating demand is based on hourly loads. </div>
<div><br>
</div>
<div>What do you think about it? </div>
<div><br>
</div>
<div>I am not very satisfied but I will give it a try. I am sure
there is a much simpler way to do it. </div>
<div><br>
</div>
<div><br>
</div>
<div>Thanks in advance for your help. </div>
<div><br>
</div>
<div>Best regards,<br>
<br>
<div class="gmail_quote">On 1 June 2012 18:10, Damien Casetta <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:damien.casetta@gmail.com" target="_blank">damien.casetta@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,
<div><br>
</div>
<div>I am modelling a ground-source heat pump system
including a water-to-water heat pump (type 927), a
borehole heat exchanger (type 557b) and a building demand
profile. </div>
<div><br>
</div>
<div>I have read a couple of messages in the archives about
this topic but I haven´t understood correctly the few
addressing my specific issue. </div>
<div><br>
</div>
<div>Here is my point. I assume the heat pump to meet the
building demand. The aim is then to force the heat pump
load and observe how the system behaves (COP, ground loop
fluid temperatures). </div>
<div><br>
</div>
<div>I would be able to do this with an external MATLAB code
(with COP values interpolated from catalog data) but it
would be a shame not to harness TRNSYS potential (there is
no need to re-invent the wheel as I read in a previous
message). </div>
<div><br>
</div>
<div>Let me put in other words: how to control a heat pump
load? </div>
<div><br>
</div>
<div>I have read about a trick to handle this, with a "lump"
temperature but I don't get the idea behind it. Any other
explanations is welcomed. </div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>Thanks in advance,</div>
<div><br>
</div>
<div>Best regards,<span class="HOEnZb"><font color="#888888"><br
clear="all">
<div><br>
</div>
<div><br>
</div>
-- <br>
<div><font color="#999999"><b>Damien Casetta</b></font></div>
<div><br>
</div>
<div><font color="#009900"><span
style="line-height:19px;font-size:13px;font-family:sans-serif"><b>Chalmers
University of Technology </b></span>| Energy
and Environment</font><span
style="color:rgb(153,153,153)"> </span><font
color="#999999">| Exchange student</font></div>
<div><font color="#3366FF"><b>INSA Lyon</b> Génie
Energétique et Environnement</font> <span
style="color:rgb(153,153,153)">| Elève ingénieur</span> </div>
<div> <span style="color:rgb(153,153,153)"> <br>
<a moz-do-not-send="true"
href="tel:%2B46.7.60.66.31.45"
value="+46760663145" target="_blank">+46.7.60.66.31.45</a><br>
</span></div>
<div><font color="#999999"><a moz-do-not-send="true"
href="tel:%2B33.6.71.78.03.75"
value="+33671780375" target="_blank">+33.6.71.78.03.75</a></font></div>
<br>
</font></span></div>
</blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
-- <br>
<div><font color="#999999"><b>Damien Casetta</b></font></div>
<div><br>
</div>
<div><font color="#009900"><span
style="font-family:sans-serif;font-size:13px;line-height:19px;background-color:rgb(255,255,255)"><b>Chalmers
University of Technology </b></span>| Energy and
Environment</font><span style="color:rgb(153,153,153)"> </span><font
color="#999999">| Exchange student</font></div>
<div><font color="#3366FF"><b>INSA Lyon</b> Génie Energétique et
Environnement</font> <span style="color:rgb(153,153,153)">|
Elève ingénieur</span> </div>
<div> <span style="color:rgb(153,153,153)"> <br>
+46.7.60.66.31.45<br>
</span></div>
<div><font color="#999999">+33.6.71.78.03.75</font></div>
<br>
</div>
<br>
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<pre class="moz-signature" cols="72">--
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
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>
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