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<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;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='mso-list:Ignore'>a)<span style='font:7.0pt "Times New Roman"'>
</span></span><![endif]>higher reflectances,<o:p></o:p></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='mso-list:Ignore'>b)<span style='font:7.0pt "Times New Roman"'>
</span></span><![endif]>better heat-removal from luminaires, and<o:p></o:p></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='mso-list:Ignore'>c)<span style='font:7.0pt "Times New Roman"'>
</span></span><![endif]>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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