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<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=855463715-01022007>Aaron,
are these buildings in design phase, or are you modeling existing
buildings?</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=855463715-01022007></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=855463715-01022007>If
existing, I'd suggest getting everything into the program as best you can first,
and then adjusting the infiltration parameters last until you match whatever
calibration data you have.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=855463715-01022007></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=855463715-01022007>For
buildings in the design phase it is difficult since the future infiltration may
depend upon many variables, including the quality of the contractor and
operations of the building which you can only estimate at this phase.
While we understand the causes of infiltration and the variables you mention
that affect it, infiltration is still hard to quantify based on values of
factors that you don't know and whether or not the weather data that you do
have is representative concerning wind variables.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=855463715-01022007></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=855463715-01022007>One
solution is to choose some moderate value. Then you could vary that
value by +/-some percentage and see if the "answer" you are looking for
from the energy simulation changes depending on the values.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=855463715-01022007></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=855463715-01022007>Hope
this helps!</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=855463715-01022007></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=855463715-01022007>David</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=855463715-01022007></SPAN></FONT> </DIV><BR>
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<FONT face=Tahoma size=2><B>From:</B> bldg-sim@gard.com
[mailto:bldg-sim@gard.com] <B>On Behalf Of </B>Dahlstrom,
Aaron<BR><B>Sent:</B> Wednesday, January 31, 2007 8:29 PM<BR><B>To:</B>
bldg-sim@gard.com<BR><B>Subject:</B> [bldg-sim] how much cold air infiltration
can I really expect?<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV><SPAN class=426371202-01022007><FONT face=Arial size=2>I have noticed
that infiltration makes up most of the winter heating load for several
high-bay single-story commercial buildings I'm modeling. (big-box
retailer, light manufacturing facility)</FONT></SPAN></DIV>
<DIV><SPAN class=426371202-01022007><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=426371202-01022007><FONT face=Arial size=2>I've used a
variety of methods - ACH estimates, CFM / so of facade (per ASHRAE F27.10),
and Area(crack) x Velocity(winter wind) - to estimate
infiltration.</FONT></SPAN></DIV>
<DIV><SPAN class=426371202-01022007><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=426371202-01022007><FONT face=Arial size=2>Have other people
stuck with these methods? Or does anyone </FONT></SPAN><SPAN
class=426371202-01022007><FONT face=Arial size=2>know of better ways to
estimate infiltration?</FONT></SPAN></DIV>
<DIV><SPAN class=426371202-01022007><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><EM><FONT face="Bookman Old Style">Aaron Dahlstrom</FONT></EM></DIV>
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