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<DIV><FONT size=2>Bonjour Hugues,</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>I'm unaware of any single program that automatically sets
this up. A very discrete finite-... 3D conduction model would be desirable, but
depending on your specific needs, ESP-r would be a very good candidate as an
annual assessment tool. I've used ESP-r for underground air culvert
assessment in the past and a couple of graduate students have used ESP-r for
similar studies (Y. Jeong, a grad student at Concordia, and another
student in Norway (a PhD student I believe) have both used ESP-r for
assessing the Media School in Norway, which has an underground air
culvert).</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>In Jeong's case, the culvert is modeled as one zone, but it is
fairly straightfoward in ESP-r to subdivide this in, let's say, 10 zones (e.g.,
a 40m culvert could be made up of ten 4m segments) - that's what I do. This will
give you a more detailed assessment, e.g., of culvert surface temperatures along
the airflow path (useful for condensation assessment or to see just how
effective the first segments of the culvert are in relation to the last ones).
ESP-r also allows you to set up an airflow network, but 'scheduled' airflows
might be OK for your needs.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>The main challenge is setting up the surface boundary
conditions. Without setting up a 3D conduction model in ESP-r (available,
but not for the faint-hearted), you'll have to specify boundary conditions
for each surface. If the culvert is deep enough, you can just feed it
monthly ground profiles for ~¾ of the surfaces, with harmonics
calculated with standard models (see Maitos and Argiriou) - the same
models used for ground-coupled heat pump simulation. If it's deep enough, the
daily variations will be minor (~ ±1°C during the course of a month). The
remaining ~¼ of the surfaces will more likely feel the effect of the nearby
ground surface, so ambient air might be more suitable as a surface boundary
condition. If the culvert is very close to the ground surface, then it's a bit
more tricky - maybe ~½ of the surfaces need ambient air as a boundary condition.
You can of course 'tweak' the model to see just how sensible it is to variable
changes.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Another point is setting up the right surface element
'constructions' so on one hand it remains numerically stable, and on the other
the constructions remain 'thick' enough so that using monthly profiles remains
valid (at least conceptually). </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Transsolar have modeled culverts for other energy consultants
in the past - maybe they've set up some basic modeling approach in TRNSYS (?).
</FONT><FONT size=2>Simpler empirical approaches are available: Argiriou and
Maitos give an overview of existing models found in the literature.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Good luck,</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>----</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Some references:</FONT></DIV>
<DIV>
<P><FONT size=2>Jeong, Y., and Haghighat, F. (2002) "Modeling of a hybrid
ventilated building, Grong School" <I>Proceedings of the 4th International Forum
on Hybrid Ventilation: An Integrated Solution for Ventilation, Health and
Energy</I>, Montreal pp.198-207.</FONT></P></DIV>
<DIV>
<P><FONT size=2>Maitos, A. (1999) "Cooling with underground air ducts" MSc
Thesis. University of Strathclyde: Glasgow. 68p.</FONT></P>
<P><FONT size=2>Argiriou, A.A. (1996) "Ground cooling" in <I>Passive Cooling of
Buildings</I>. M.J. Santamouris and D.N. Asimakopoulos, eds., James & James:
London. pp.360-403.</FONT></P>
<P><FONT size=2>Kumar, R., Ramesh, S., and Kaushik, S.C. (2003) "Performance
evaluation and energy conservation potential of earth-air-tunnel system coupled
with non-air-conditioned building" <I>Building and Environment</I> 38
pp.807-813.</FONT></P>
<P><FONT size=2>Lay, R.M. (2003) "Earth Rangers Wildlife Centre - case study of
concrete use for energy efficiency" <I>Proceedings of the 8th Environmental and
Sustainable Engineering Specialty Conference of the Canadian Society for Civil
Engineering</I>, Moncton.</FONT></P>
<P><FONT size=2>Sawhney, R.L., Buddhi, D., and Thanu, N.M. (1999) "An
experimental study of summer performance of a recirculation type underground
airpipe air conditioning system" <I>Building and Environment</I> 34(2)
pp.189-196.</FONT></P>
<P><FONT size=2>----</FONT></P></DIV>
<DIV><FONT size=2>Denis Bourgeois<BR>PhD student/doctorant<BR>École
d'architecture, Université Laval<BR></FONT><A
href="mailto:denis.bourgeois@arc.ulaval.ca"><FONT
size=2>denis.bourgeois@arc.ulaval.ca</FONT></A></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>----</FONT></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=huguesboivin@sympatico.ca
href="mailto:huguesboivin@sympatico.ca">Hugues Boivin</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=BLDG-SIM@gard.com
href="mailto:BLDG-SIM@gard.com">BLDG-SIM@gard.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, November 21, 2003 1:11
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [BLDG-SIM] earth-air exchanger
(earth channels)</DIV>
<DIV><BR></DIV>
<DIV><FONT size=2>Does anyone knows a simulation tool to evaluate energy
savings by earth-to-air exchanger (earth channels) ?</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Thank you.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Hugues Boivin</FONT></DIV>
<DIV><FONT size=2>Mechanical Engineer</FONT></DIV>
<DIV><FONT size=2>Laval University</FONT></DIV>
<DIV><FONT size=2>GRAP (Groupe de recherche en ambiance physique)</FONT></DIV><PRE>
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