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<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff
size=2>Brian,</FONT></SPAN></DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff size=2>as far
as I know does TAS use transfer-functions for the energy transport through
components like walls and glazings; thus the internal surface temperatures of
glazings arenot modelled in a correct way. As these internal surface
temperatures are dominating the vertical near surface air flow (the development
of boundary layers), a more reliable simulation tool should be used.
</FONT></SPAN><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff
size=2>I am using ESP-r from ESRU, Joe Clark, which is based on
1-D-heatconduction modelled via finite differences algorithm; thus the
absorption of solar radiation within the single panes can be calculated as well
as the resulting heat fluxes to external and internal surfaces. This yield more
correct internal surface temperatures.</FONT></SPAN></DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff size=2>But
you have asked for detailled CFD-studies about natural ventilation: This is
currently a challenging task !</FONT></SPAN></DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff size=2>The
basic problem is that the well known high resolving CFD simulation tools like
CFX-5 or Fluent are not able to simulate a longer period of time (due to the
high resolution this would require a huge amount of computer power), i.e.
currently simulation time is maximal a complete day; on the other hand the
storage of heat in building's mass (floors, walls, ceilings, etc.) shows a
strong effect onto the temperatures, but to get a stable solution it
will take a longer period of time (simulation time of at least 14 days ore more,
depending on the amount of storage mass). This is the reason, why you have to
use a zonal based simulation tool - like ESP-r - for the starting period of the
simulation (i.e. the first 2..3 weeks) and then you have to couple it with a CFD
simulation tool. This coupling can be done either via internal surface
temperatures (as boundary conditions for the CFD simulation) or - even more
better - with wall heat fluxes (which provides a temperature distribution on the
internal surfaces).</FONT></SPAN></DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff
size=2>Currently ESP-r has the facility to couple the zonal based simulation
with an internal CFD-capability; but there are restrictions due to the number of
windows (only two openings are allowed); also the analyses of the
CFD-results shows some problems. </FONT></SPAN></DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff size=2>These
were the reasons why we coupled ESP-r with the well known CFD-simulation
tool CFX-5; we used the output from ESP-r (wall heat fluxes and surface
absorptions, air flow rates towards outside (ambient air) calculated via an
air-flow-network model) as input values for the CFD-model and we got some nice
results. If you are interested in I could send you some
examples.</FONT></SPAN></DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff size=2>Hope
these informations help you. If you have further questions, don´t hesitate to
contact me.</FONT></SPAN></DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff
size=2>-Gunter</FONT></SPAN></DIV>
<DIV><SPAN class=047461006-22102003>
<P><FONT size=2>--------------------------------------------<BR>Dr.-Ing. Gunter
Pültz<BR>Müller-BBM GmbH<BR>Robert-Koch-Str. 11<BR>82152 Planegg bei
München<BR>Telefon +49 (89) 85602-336<BR>Telefax +49 (89) 85602-111<BR><A
href="http://www.mbbm.de/"
target=_blank>http://www.mbbm.de</A><BR>email:plz@mbbm.de</FONT>
</P></SPAN></DIV>
<DIV><SPAN class=047461006-22102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma><FONT
size=2><SPAN class=047461006-22102003><FONT face=Arial
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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma><FONT
size=2><SPAN class=047461006-22102003> </SPAN>-----Original
Message-----<BR><B>From:</B> Brian Thornton
[mailto:bthornton@glumac.com]<BR><B>Sent:</B> Wednesday, October 22, 2003 1:06
AM<BR><B>To:</B> BLDG-SIM@gard.com<BR><B>Subject:</B> [BLDG-SIM] natural
ventilation analysis tools<BR><BR></DIV></FONT></FONT>
<P><FONT face=Arial size=2>Does anyone have experience with CFD, and non-CFD
analysis tools for design and energy analysis of natural ventilation?</FONT>
</P>
<P><FONT face=Arial size=2>Tas is one I have heard a lot about lately.</FONT>
</P>
<P><FONT face=Arial size=2>Can anyone describe their experience in learning,
using, providing usable and correct results, and extrapolating results to
annual energy usage/savings?</FONT></P>
<P><FONT face=Arial size=2>Any other software that provides at least some 2-D
or 3-D CFD, and hourly thermal calculations for natural ventilation?</FONT>
</P>
<P><FONT face=Arial size=2>Thanks,</FONT> </P>
<P><FONT face=Arial size=2>Brian </FONT></P>
<P><FONT face=Arial size=2>Brian Thornton, P.E.</FONT> <BR><FONT face=Arial
size=2>Lead Engineer, Energy Services</FONT> <BR><U><B><I><FONT
face="Arial Black" color=#000000 size=5>GLUMAC</FONT></I></B></U> <BR><B><FONT
face=Arial color=#000000 size=1>I N T E R N A T I O N A L</FONT></B> <BR><FONT
face=Arial size=2>320 SW Washington, Suite 200</FONT> <BR><FONT face=Arial
size=2>Portland, Oregon 97204</FONT> </P>
<P><FONT face=Arial size=2>503.227.5280 Phone </FONT><BR><FONT
face=Arial size=2>503.274.7674 Fax</FONT> </P>
<P><FONT face=Arial size=2>www.Glumac.com</FONT> </P>
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