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Eleftherios,<br>
I think that you are mixing aspects of "energy rate control" and
"temperature level control" and I would suggest that you get the
tutorial called "Temperature Level Control from Energy Rate Control"
available at
<a class="moz-txt-link-freetext" href="http://sel.me.wisc.edu/trnsys/downloads/tutorials_and_examples/tutex17.htm">http://sel.me.wisc.edu/trnsys/downloads/tutorials_and_examples/tutex17.htm</a>
as it will show you the steps necessary to take a "loads" based
simulation and turn it into a simulation that uses thermostats and
real equipment.<br>
<br>
The reason that your simulation is giving you such low (and
probably high) outlet water temperatures is that you have a constant
capacity heat pump connected to a controller. If the capacity of the
heat pump is very large (and it probably is if you have sized it to
the peak load of the zone) then during times when there is only a
little bit of load on the heat pump, it is still turning on at
basically full capacity. Since you have a very tiny flow rate during
those periods, you are getting a very big temperature change across
the heat pump. In most systems like this the flow rate is not
changed during low demand periods so the temperature change does not
increase. If you do want to investigate the impact of a variable
flow rate system then you probably also need to look at the use of a
variable capacity heat pump that does not always run at or near its
rated capacity.<br>
Kind regards,<br>
David<br>
<br>
<br>
<br>
<br>
<div class="moz-cite-prefix">On 6/3/2014 04:17, Eleftherios
Bourdakis wrote:<br>
</div>
<blockquote
cite="mid:CAH9U-DiRg1vAGwKL1vJAcT1AE4SSgZc_EGcy-rprw8gdtUZMJA@mail.gmail.com"
type="cite">
<div dir="ltr">Dear All,<br>
<br>
I'm trying to simulate a radiant cooling floor for an office
room. Firstly I simulated the model I made in TRNBuild by using
the 'heating' and 'cooling' options of it in order to find the
maximum cooling demand of my room. <br>
Then I implemented the active layer in the floor and altered my
model in Simulation Studio in the following way:
<div>1. I entered in an excel file the cooling demand I got from
the first simulation.</div>
<div>2. I'm calling this excel file in order to define the
hourly flow rate by this formula </div>
<div style="text-align:center">'Hourly_flow_rate=Max_flow_rate*(Hourly_cooling_demand/Max_cooling_demand)</div>
<div>and I use this value as an input in the Type941 Air-Water
Heat Pump.</div>
<div>3. I use a Type2 AquastatC for the cooling control signal
of the Heat Pump. The 'Temperature to watch' of the Type2 is
the Operative temperature output from my Type56 model and the
setpoint for the Type2 is 27oC, while the deadband is ±0.5oC.</div>
<div>4. In the Heat Pump I use as 'Inlet liquid temperature' a
constant value of 15oC and I defined the 'Rated cooling power'
as the maximum cooling demand I got from the 1st simulation
(Is this correct?)</div>
<div>5. Since in my heat gains I also have occupants, I included
a ventilation system consisting of a Type112b fan, a Type92, a
Type 121b and Type108 as it was described in the 'Temperature
Level Control Tutorial' in order mainly to remove the latent
load.</div>
<div><br>
</div>
<div>My problem is that in my annual simulation while the 'Inlet
liquid temperature' is 15oC suddenly it is reduced to values
such as -50oC or -100oC and then back at 15oC! Instead of
using an equation for defining the 'Inlet liquid temperature'
I used the output of the Type56 'fluid outlet temperature of
active layer' but I got similar results. <br>
<br>
Do you know why this is happening? Should I use a component to
define the 'Inlet liquid temperature'?</div>
<div>Thank you in advance for answering my question.<br>
<br>
Best regards,<br>
Eleftherios</div>
</div>
<br>
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<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>
<a class="moz-txt-link-freetext" href="http://www.tess-inc.com">http://www.tess-inc.com</a>
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