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    Zhe,<br>
      TRNBuild has two concepts that are important here. An "airnode" is
    an area of the building that can be represented by a single air
    temperature. A "radiation zone" is volume within the building in
    which all of the walls can "see" each other. How you decide to break
    up the building into airnodes and radiation zones depends on what is
    crossing the boundaries between them. For example if you have an
    atrium with a glass roof or a glass wall there is going to be
    vertical stratification (i.e. multiple airnodes) and it is the solar
    radiation that is going to cross the airnode boundaries so you'll
    combine those airnodes into a single radiation zone. Virtual
    surfaces are used as boundaries between the airnodes because
    radiation can cross a virtual surface.<br>
    <br>
      In your case, I think you have a greenhouse attached to the side
    of a building so that there will certainly be a temperature
    difference between the greenhouse and the rest of the building but
    there probably won't be very much radiation crossing the boundary
    between the two. In this case there isn't any need to define a
    virtual surface because there isn't much radiation passing. You can
    define there to be a "wall" between the two airnodes when you are
    drawing the building in SketchUp. Then when you go to TRNBuild, you
    can set that wall's properties so that it has a very low thermal
    resistance (high u value). In this way the wall will allow you to
    define convection between the two airnodes and there will be little
    resistance to conduction heat transfer. <br>
    <br>
    best,<br>
     David<br>
    <br>
    <br>
    <br>
    <div class="moz-cite-prefix">On 07/20/2015 19:17, Zhe Kong wrote:<br>
    </div>
    <blockquote
cite="mid:CAEV5NyeDn3BXPPaT-ieS-3FjC4bo22OPyKU7yhZe0nOs=b2CQQ@mail.gmail.com"
      type="cite">
      <div dir="ltr">Hi everyone:
        <div>I just star learning Trnsys and come up with a basic
          inquiry. Does anyone know how to create two airnodes within
          one zone in sketchup before exporting into Trnsys? <span
style="color:rgb(0,0,0);font-family:Calibri,Arial,Helvetica,sans-serif;font-size:16px">We
            want to build a one-floor greenhouse mostly enclosed by
            glazing. The sloped roofs are also in glazing. We want to do
            the calculation concerning solar radiation and heat flow
            without HVAC system. </span></div>
        <div>
          <div
style="color:rgb(0,0,0);font-family:Calibri,Arial,Helvetica,sans-serif;font-size:16px;margin-top:0px;margin-bottom:0px"><br>
          </div>
          <div
style="color:rgb(0,0,0);font-family:Calibri,Arial,Helvetica,sans-serif;font-size:16px;margin-top:0px;margin-bottom:0px">Currently
            we built two zones (the plant one and the air one) with the
            mutual surface set as virtual surface; however, even the two
            virtual surfaces disappeared when being exported into
            Trnsys, the two zones seemed to have no air flow connection.
            The results show that the plant zone has small range of
            temperature change, while the air zone has a much larger
            range. We realized we should build the sketchup model with
            two airnodes and one zone, but we didn't figure out how to
            do it. Another question is, in that case, is there anyway we
            can set different inputs according to the two airnodes?</div>
          <div><br>
          </div>
          <div>Thank you in advance. </div>
          -- <br>
          <div class="gmail_signature">
            <div><em style="font-family:'Times New
                Roman';font-size:medium;background-color:rgb(255,255,255)"><span
                  style="font-family:arial,helvetica,sans-serif">Zhe
                  Kong</span></em></div>
            <div><em style="font-family:'Times New
                Roman';font-size:medium;background-color:rgb(255,255,255)"><span
                  style="font-family:arial,helvetica,sans-serif">PhD
                  Student</span></em><br style="font-family:'Times New
                Roman';font-size:medium;background-color:rgb(255,255,255)">
              <em style="font-family:'Times New
                Roman';font-size:medium;background-color:rgb(255,255,255)"><span
                  style="font-family:arial,helvetica,sans-serif">University
                  of Wisconsin - Milwaukee </span></em><br
                style="font-family:'Times New
                Roman';font-size:medium;background-color:rgb(255,255,255)">
              <em style="font-family:'Times New
                Roman';font-size:medium;background-color:rgb(255,255,255)"><span
                  style="font-family:arial,helvetica,sans-serif">School
                  of Architecture and Urban Planning </span></em><br
                style="font-family:'Times New
                Roman';font-size:medium;background-color:rgb(255,255,255)">
              <em style="font-family:'Times New
                Roman';font-size:medium;background-color:rgb(255,255,255)"><span
                  style="font-family:arial,helvetica,sans-serif">2131 E.
                  Hartford Ave, Milwaukee, WI 53211 </span></em><br
                style="font-family:'Times New
                Roman';font-size:medium;background-color:rgb(255,255,255)">
              <em style="font-family:'Times New
                Roman';font-size:medium;background-color:rgb(255,255,255)"><span
                  style="font-family:arial,helvetica,sans-serif">Office
                  327</span></em></div>
          </div>
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      <pre wrap="">_______________________________________________
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</pre>
    </blockquote>
    <br>
    <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>
<a class="moz-txt-link-freetext" href="http://www.trnsys.com">http://www.trnsys.com</a></pre>
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