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Jan-Willem,<br>
<br>
<br>
<br>
<blockquote cite="mid:001601c8ecbd$1c631a10$97140a0a@chri.local"
type="cite">
<div class="Section1">
<p class="MsoPlainText"><i><font face="Courier New" size="2"><span
style="font-size: 10pt; font-style: italic;" lang="EN-GB">When
defining a new wall, TRNBUILD
calculates a standard U-value determined <o:p></o:p></span></font></i></p>
<p class="MsoPlainText"><i><font face="Courier New" size="2"><span
style="font-size: 10pt; font-style: italic;" lang="EN-GB">with
combined heat transfer
coefficients of 7.7 W/m²K inside and 25 W/m²K <o:p></o:p></span></font></i></p>
<p class="MsoPlainText"><i><font face="Courier New" size="2"><span
style="font-size: 10pt; font-style: italic;" lang="EN-GB">outside (see
volume 6 page 23).
These U-values are correct for a vertical <o:p></o:p></span></font></i></p>
<p class="MsoPlainText"><i><font face="Courier New" size="2"><span
style="font-size: 10pt; font-style: italic;" lang="EN-GB">wall
separating an inside
environnement from an outside environnement, but <o:p></o:p></span></font></i></p>
<p class="MsoPlainText"><i><font face="Courier New" size="2"><span
style="font-size: 10pt; font-style: italic;" lang="EN-GB">not for
horizontal walls and inside
vertical walls. Does TRNBUILD take <o:p></o:p></span></font></i></p>
<p class="MsoPlainText"><i><font face="Courier New" size="2"><span
style="font-size: 10pt; font-style: italic;" lang="EN-GB">these
distinctions into account or
does it use these two standard <o:p></o:p></span></font></i></p>
<p class="MsoPlainText"><i><font face="Courier New" size="2"><span
style="font-size: 10pt; font-style: italic;" lang="EN-GB">coefficients
(7 and 25) for every
wall types ?</span></font></i></p>
</div>
</blockquote>
The values displayed by TRNBuild always assume the 7.7 inside and 25
outside regardless of wall orientation. Those values are NOT the ones
used during the simulation. During the simulation, the inside and
outside convection coefficients are determined by whatever method you
have used in TRNBuild to specify them (input, constant value, schedule,
or internal calculation). If you want to know the exact u-value of the
wall, you choose the appropriate surface NTYPE among the Type56
outputs. The user does not have the ability to change the radiation
coefficient in TRNSYS 16, only the convective portion. The algorithms
used if you choose the "internal calculation" are described both in the
Type56 mathematical description (volume 6) and in the Type80
mathematical description.<br>
Kind regards,<br>
David<br>
<br>
<br>
<blockquote cite="mid:001601c8ecbd$1c631a10$97140a0a@chri.local"
type="cite">
<div class="Section1">
<p class="MsoPlainText"><i><font face="Courier New" size="2"><span
style="font-size: 10pt; font-style: italic;" lang="EN-GB"><o:p></o:p></span></font></i></p>
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
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Thermal Energy System Specialists (TESS), LLC
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USA
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