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    <p>Amaia,</p>
    <p>  There could be two things I think. First, you're right that you
      need to take into account the change in energy stored in the tank.
      Type4 has an output that you can use. Second, make sure you are
      using a small timestep (maybe 5 minutes). With large timesteps you
      often get problems with energy balances.</p>
    <p>kind regards,</p>
    <p> David</p>
    <p><br>
    </p>
    <br>
    <div class="moz-cite-prefix">On 10/07/2018 13:57, Amaia Zuazua Ros
      via TRNSYS-users wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAH7+1HuUhtY-X+b8WGZv=Rfm2yp7wHi+Uk=y6i=fq90VMftMcQ@mail.gmail.com">
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        <div>Hi <span class="" id=":1bt.3" tabindex="-1" style="">TRNsys</span>
          users,</div>
        <div><br>
        </div>
        <div>I am simulating a water to water chiller coupled to two
          storage tanks one each side of the chiller. It's the first
          time that I work with tanks (I'm using type 4), and I
          understand that the energy balance should be accomplish, I
          mean, the total energy coming from the source should be the
          same than the energy going to the load, but this is not
          happening in my case with the condenser side of the chiller
          (the <span class="" id=":1bt.4" tabindex="-1" style="">annual</span>
          totals have around 10% difference) and still the system seems
          to work (the idea is to simulate a radiative system that
          dissipates the heat from the condenser). I don't know if it
          can be related to the internal energy change of the tank.
          Could some one give a bit further explanation/information
          about this?</div>
        <div><br>
        </div>
        <div>Thanks in advance!</div>
        <div><br>
        </div>
        <div><span class="" id=":1bt.5" tabindex="-1" style="">Amaia</span></div>
      </div>
      <br>
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</pre>
    </blockquote>
    <br>
    <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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