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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Have not modeled a DSF with natural
ventilation but may be possible in EnergyPlus. You would have to create a
separate zone as the double skin and use their bulk airflow modeling
capabilities to do this. Also read the article by Dr. Karl Gertis from an
email I received previously. This should get you started. <st1:country-region
w:st="on"><st1:place w:st="on">Germany</st1:place></st1:country-region> it
would seem would be the best place to look for buildings having a Nat Vent
DSF. Good luck<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>1. You wrote:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>[I<st1:PersonName w:st="on">'</st1:PersonName>m concerned
about insect screens affecting the buoyancy driven airflow for a double skin
façade.]<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Dr. Karl Gertis (director of the Fraunhofer Institute of Building
Physics in Stuttgart, Germany) provides a critical review of double-skin
façades in one of his article and cites some problems in the literature
regarding research related to Glass Double Facade e.g. “<i><span
style='font-style:italic'>window insect screens cannot be used with natural
ventilation because the airflow is too weak to overcome the pressure loss over
the air filter.</span></i>”<i><span style='font-style:italic'><o:p></o:p></span></i></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>For more information about the article please go to the following link:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><a href="http://gaia.lbl.gov/hpbf/perfor_c.htm"
title="http://gaia.lbl.gov/hpbf/perfor_c.htm">http://gaia.lbl.gov/hpbf/perfor_c.htm</a><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>2. You wrote:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>[I was wondering if anyone new of some papers that have
covered the airflow properties of insect screens or can give me some
information off hand.]<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Book Antiqua"><span style='font-size:
12.0pt;font-family:"Book Antiqua"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> Jun Tanimoto,
Jun and Kimura, Ken-ichi (1997), <i><span style='font-style:italic'>Simulation
study on an air flow window system with an integrated roll screen</span></i>, </span></font><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>Energy and
Buildings 26(3):
317-325.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>There are a few sources that also deal with the effect of insect screen
on airflow but they are specific to <u>wind driven</u> natural ventilation. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in;text-indent:-.5in'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> Swami,
M.V. and Chandra, S. (1988),<i><span style='font-style:italic'> Correlations
for pressure distribution on buildings and calculation of natural ventilation
airflow</span></i>, ASHRAE Transactions, Vol. 94, Part 1, pp 243-266.<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in;text-indent:-.5in'><font size=2
face=Arial><span style='font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>This paper provides a procedure for determining ventilation rates based
on the Vickery algorithm (1983), however, assumption inherent in this procedure
is that there is no stack effect.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in;text-indent:-.5in'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> Givoni,
B. (1981), <i><span style='font-style:italic'>Man, Climate and Architecture</span></i>,
<st1:State w:st="on"><st1:place w:st="on">New York</st1:place></st1:State>: Van
Nostrand Reinhold.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>On pp 304 Section 15.8 Givoni discusses the effect of fly-screens on
ventilation. He quotes van Straaten, the decrease in total airflow, caused by a
16 mesh, 30 gauge wire screen is about 60% and 50% when the wind speeds are
respectively 1.5 and 2 mph and only about 25% when the wind speed is 10 mph.<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Straateen, J. F. van, (1967), <i><span
style='font-style:italic'>Thermal performance of buildings</span></i>, Elsevier
Publishing Co Ltd<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>3. You wrote:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>[I<st1:PersonName w:st="on">'</st1:PersonName>m also
wondering how to incorporate their effects on the flow by use of discharge
coefficients and pressure loss coefficients.]<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Andersen, Karl T. (1995), <i><span style='font-style:
italic'>Theoretical considerations on natural ventilation by thermal buoyancy,</span></i>
ASHRAE Trans. 1995, Vol.101, Part 2, Paper number SD-95-14-1, 1103-1117<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>For abstract please visit the following link:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><a
href="http://resourcecenter.ashrae.org/store/ashrae/newstore.cgi?itemid=17248&view=item&categoryid=452&categoryparent=452&page=1&loginid=1357156"
title="http://resourcecenter.ashrae.org/store/ashrae/newstore.cgi?itemid=17248&view=item&categoryid=452&categoryparent=452&page=1&loginid=1357156">http://resourcecenter.ashrae.org/store/ashrae/newstore.cgi?itemid=17248&view=item&categoryid=452&categoryparent=452&page=1&loginid=1357156</a><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>In the section ‘coefficients of interest’ the author
discusses velocity, contraction, discharge, and resistance coefficients and may
provide insight into the effect of insect screen on airflow, however, the
author does not directly relate it to the insect screen.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>There is a gap in the computation of natural ventilation research
especially in terms of discharge coefficients and pressure loss coefficients as
Ansyley (1999) and Linden (1999) point out that the computation of natural
ventilation lacks experimental data and borrows the discharge coefficient and
flow resistance of openings derived from data traditionally used for fluid flow
in pipes and resistance values traditionally used in computation of mine
ventilation. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-indent:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Ansyley R. (1999), <i><span style='font-style:italic'>Unresolved
Issues in Natural Ventilation for Thermal Comfort, </span></i>HybVent
Forum’99<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-indent:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><st1:City w:st="on"><st1:place
w:st="on"><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>Linden</span></font></st1:place></st1:City>,
P.F, (1999), <i><span style='font-style:italic'>Fluid Mechanics of Natural
Ventilation, </span></i>Annu. Rev. Fluid Mech. 1999. 31:201–38<o:p></o:p></p>
<p class=MsoNormal><i><font size=3 face="Times New Roman"><span
style='font-size:12.0pt;font-style:italic'><o:p> </o:p></span></font></i></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Best regards,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Gaurav Mehta<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
BLDG-SIM@gard.com [mailto:BLDG-SIM@gard.com] <b><span style='font-weight:bold'>On
Behalf Of </span></b>Kingsley, Michael L.<br>
<b><span style='font-weight:bold'>Sent:</span></b> Wednesday, March 28, 2007
7:08 AM<br>
<b><span style='font-weight:bold'>To:</span></b> BLDG-SIM@gard.com<br>
<b><span style='font-weight:bold'>Subject:</span></b> [BLDG-SIM] Double-skin
facade with natural ventilation</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Has anyone modeled a building with a double-skin facade with
natural ventilation? Any pointers would be greatly appreciated.
Also, personal experiences or references that indicate the effectiveness of
this type of system in a northern climate would be helpful too.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thanks in advance!<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p style='margin:0in;margin-bottom:.0001pt'><b><font size=4 face=Tahoma><span
style='font-size:13.5pt;font-family:Tahoma;font-weight:bold'>Michael L.
Kingsley</span></font></b><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<pre><font size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>==================<o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>You received this e-mail because you are subscribed <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>to the BLDG-SIM@GARD.COM mailing list. To unsubscribe <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>from this mailing list send a blank message to <o:p></o:p></span></font></pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>BLDG-SIM-UNSUBSCRIBE@GARD.COM<o:p></o:p></span></font></pre></div>
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