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<p class=MsoNormal><span style='color:#1F497D'>Thanks James,<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>I’m beginning to see how there
could be a difference: especially since the office modeled does use a VAV
system and the food store is a single storey building with 100,000 sq. ft roof.
It would seem that the roof loads have the greater influence because its energy
costs savings are 30 – 40% greater than the 8-storey office building with
15,000 sq. ft. roof for four locations (including Orlando), and 70% higher for Charlotte.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>BTW, it is claimed that the
life-cycle payback is between 5 – 11 years for the office, and 0.9 –
1.7 years for the food store.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Paul Hay<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Managing Partner<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>PAUL HAY Consultants<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><i><span style='color:#1F497D'>Capital Project Planning and
Management<o:p></o:p></span></i></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>15a Cassia Park Road<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Kingston 10<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Jamaica, W.I.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>tel: 1 (876) 756-0631<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>cel: 1 (876) 324-4274<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>fax: 1 (876) 756-0631<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>web: www.phcjamaica.com<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>e-mail: paul.hay@phcjamaica.com<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
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<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> James V. Dirkes II
P.E. [mailto:jvd2pe@tds.net] <br>
<b>Sent:</b> Thursday, January 08, 2009 10:40 AM<br>
<b>To:</b> phay@phcjamaica.com; 'BLDG-SIM'<br>
<b>Subject:</b> RE: [Bldg-sim] Suspended ceilings vs. open plenums<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Dear Paul,</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>In theory, the return plenum is warmer than the occupied space, so
the wall and, especially, roof loads do not affect the space in the same
way. This will give a warmer coil entering condition and resulting
smaller coil, fan, duct, motor, wiring, electrical service, etc.</span><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>The ACTUAL difference will be small and may not be worth the
additional analysis and load calculations. You could argue that a VAV
system will realize the benefits, since it will "see" the space load
only and reduce volume to suit.</span><span style='font-size:12.0pt;font-family:
"Times New Roman","serif"'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Another consideration is whether the life cycle energy benefits
outweigh the differential cost to install and maintain the suspended
ceiling.... I suspect they do, but am uncertain re: ROI.</span><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>
</div>
<p class=MsoNormal align=center style='text-align:center'><b><span
style='font-size:13.5pt'>The Building Performance Team<br>
</span>James V. Dirkes II, P.E., LEED AP<br>
</b>1631 Acacia Drive NW<br>
Grand Rapids, MI 49504<br>
616 450 8653<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p>
<div class=MsoNormal align=center style='text-align:center'><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'>
<hr size=2 width="100%" align=center>
</span></div>
<p class=MsoNormal style='margin-bottom:12.0pt'><b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> bldg-sim-bounces@lists.onebuilding.org
[mailto:bldg-sim-bounces@lists.onebuilding.org] <b>On Behalf Of </b>P. Hay<br>
<b>Sent:</b> Thursday, January 08, 2009 10:19 AM<br>
<b>To:</b> BLDG-SIM<br>
<b>Subject:</b> [Bldg-sim] Suspended ceilings vs. open plenums</span><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>
<p class=MsoNormal>Hi all,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I recently came across a Life Cycle Analysis of Suspended
Ceilings vs. Open Plenums, initiated by CISCA [Ceiling and Interior System
Construction Association ( <a href="http://www.cisca.org">www.cisca.org</a> )]
which concluded that suspended ceilings are more energy efficient because they
have:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoListParagraph style='text-indent:-.25in'>a)<span style='font-size:
7.0pt;font-family:"Times New Roman","serif"'> </span>higher
reflectances,<o:p></o:p></p>
<p class=MsoListParagraph style='text-indent:-.25in'>b)<span style='font-size:
7.0pt;font-family:"Times New Roman","serif"'> </span>better
heat-removal from luminaires, and<o:p></o:p></p>
<p class=MsoListParagraph style='text-indent:-.25in'>c)<span style='font-size:
7.0pt;font-family:"Times New Roman","serif"'>
</span>use lower static pressure and fan power.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I can understand (a) and (c) but (b) leaves me suspicious
that the return-air plenum was not considered in this study. As I
understand it, return-air plenums can be defined as separate zones from the
usable spaces (in this case: an office or a food store) but the suspended
ceilings are adiabatic. So , other than the savings for lighting and fan,
I really don’t understand how there could be significant savings for the
HVAC system if the overall height of the rooms (plenum & usable space) is
identical, and cooling load of plenums are considered. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Is there something I’m missing?<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Paul Hay<o:p></o:p></p>
<p class=MsoNormal>Managing Partner<o:p></o:p></p>
<p class=MsoNormal>PAUL HAY Consultants<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><i>Capital Project Planning and Management<o:p></o:p></i></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>15a Cassia Park Road<o:p></o:p></p>
<p class=MsoNormal>Kingston 10<o:p></o:p></p>
<p class=MsoNormal>Jamaica, W.I.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>tel: 1 (876) 756-0631<o:p></o:p></p>
<p class=MsoNormal>cel: 1 (876) 324-4274<o:p></o:p></p>
<p class=MsoNormal>fax: 1 (876) 756-0631<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>web: www.phcjamaica.com<o:p></o:p></p>
<p class=MsoNormal>e-mail: paul.hay@phcjamaica.com<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
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