<font size="3" face="Times New Roman">
</font><div style="margin:0in 0in 0pt" class="MsoNormal"><font size="3"><font face="Times New Roman">
<p style="margin:0in 0in 0pt" class="MsoNormal">Hi everyone,</p>
</font></font></div><div style="margin:0in 0in 0pt" class="MsoNormal"><font size="3"><font face="Times New Roman"></font></font> </div><div style="margin:0in 0in 0pt" class="MsoNormal"><font size="3"><font face="Times New Roman">I found this thread from the bldg.sim archive and I
tabulated the figures in tables 5.5-1 through 5.5-8 for glass assembly
U-value for metal framing for every climate zone.</font></font></div><div><font size="3" face="Times New Roman">
</font></div><div><table style="width:291pt;border-collapse:collapse" border="0" cellspacing="0" cellpadding="0" width="388">
<colgroup><col style="width:67pt" width="89">
<col style="width:128pt" width="171">
<col style="width:48pt" span="2" width="64">
<tbody><tr style="height:15pt" height="20">
<td style="border:0.5pt solid windowtext;width:67pt;height:30pt;background-color:transparent" class="xl69" height="40" rowspan="2" width="89"><strong><font size="3" face="Calibri">Climate
Zone</font></strong></td>
<td style="border:0.5pt solid windowtext;width:128pt;background-color:transparent" class="xl69" rowspan="2" width="171"><strong><font size="3" face="Calibri">Definition</font></strong></td>
<td style="border-width:0.5pt 0.5pt 0.5pt 0px;border-style:solid solid solid none;border-color:windowtext windowtext windowtext black;width:96pt;background-color:transparent" class="xl70" width="128" colspan="2"><strong><font size="3" face="Calibri">Metal
Framing</font></strong></td>
</tr>
<tr style="height:15pt" height="20">
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;height:15pt;background-color:transparent" class="xl66" height="20"><font size="3" face="Calibri">U-Value</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl66"><font size="3" face="Calibri">SHGC</font></td>
</tr>
<tr style="height:15pt" height="20">
<td style="border-width:0px 0.5pt 0.5pt;border-style:none solid solid;border-color:windowtext;height:15pt;background-color:transparent" class="xl67" height="20"><font size="3" face="Calibri">1</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:windowtext;background-color:transparent" class="xl67"><font size="3" face="Calibri">Very Hot and Humid</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">1.20</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.25</font></td>
</tr>
<tr style="height:15pt" height="20">
<td style="border-width:0px 0.5pt 0.5pt;border-style:none solid solid;border-color:windowtext;height:15pt;background-color:transparent" class="xl67" height="20"><font size="3" face="Calibri">2</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:windowtext;background-color:transparent" class="xl67"><font size="3" face="Calibri">Hot and Humid</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.70</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.25</font></td>
</tr>
<tr style="height:15pt" height="20">
<td style="border-width:0px 0.5pt 0.5pt;border-style:none solid solid;border-color:windowtext;height:15pt;background-color:transparent" class="xl67" height="20"><font size="3" face="Calibri">3</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:windowtext;background-color:transparent" class="xl67"><font size="3" face="Calibri">Warm-Humid</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.60</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.25</font></td>
</tr>
<tr style="height:15pt" height="20">
<td style="border-width:0px 0.5pt 0.5pt;border-style:none solid solid;border-color:windowtext;height:15pt;background-color:transparent" class="xl67" height="20"><font size="3" face="Calibri">4</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:windowtext;background-color:transparent" class="xl67"><font size="3" face="Calibri">Warm</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.50</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.40</font></td>
</tr>
<tr style="height:15pt" height="20">
<td style="border-width:0px 0.5pt 0.5pt;border-style:none solid solid;border-color:windowtext;height:15pt;background-color:transparent" class="xl67" height="20"><font size="3" face="Calibri">5</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:windowtext;background-color:transparent" class="xl67"><font size="3" face="Calibri">Mixed Humid</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.45</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.40</font></td>
</tr>
<tr style="height:15pt" height="20">
<td style="border-width:0px 0.5pt 0.5pt;border-style:none solid solid;border-color:windowtext;height:15pt;background-color:transparent" class="xl67" height="20"><font size="3" face="Calibri">6</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:windowtext;background-color:transparent" class="xl67"><font size="3" face="Calibri">Mixed</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.45</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.40</font></td>
</tr>
<tr style="height:15pt" height="20">
<td style="border-width:0px 0.5pt 0.5pt;border-style:none solid solid;border-color:windowtext;height:15pt;background-color:transparent" class="xl67" height="20"><font size="3" face="Calibri">7</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:windowtext;background-color:transparent" class="xl67"><font size="3" face="Calibri">Very Cold</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.40</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.45</font></td>
</tr>
<tr style="height:15pt" height="20">
<td style="border-width:0px 0.5pt 0.5pt;border-style:none solid solid;border-color:black windowtext windowtext;height:15pt;background-color:transparent" class="xl66" height="20"><font size="3" face="Calibri">8</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl66"><font size="3" face="Calibri">Sub-arctic</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.40</font></td>
<td style="border-width:0px 0.5pt 0.5pt 0px;border-style:none solid solid none;border-color:black windowtext windowtext black;background-color:transparent" class="xl68"><font size="3" face="Calibri">0.45</font></td>
</tr>
</tbody></colgroup></table></div><div> </div><div><font size="3" face="Times New Roman">
</font><p style="margin:0in 0in 0pt" class="MsoNormal"><font size="3"><font face="Times New Roman"> I understand that SC usually has greater effect than the
U-value, I used to be under the impression that the lower the U-value the
better. It turned out that it depends on the climate zone.</font></font></p><p style="margin:0in 0in 0pt" class="MsoNormal"><font size="3"><font face="Times New Roman"></font></font> </p><p style="margin:0in 0in 0pt" class="MsoNormal">
<font size="3"><font face="Times New Roman">I also have this unusual result. They did
explain it well but I am eager to hear from other fellow simulators regarding
this matter. Or does anyone have any related articles that explain this in detail? </font></font><font size="3"><font face="Times New Roman">thanks in advance.</font></font><font size="3" face="Times New Roman">
</font></p><p style="margin:0in 0in 0pt" class="MsoNormal"><font size="3"><font face="Times New Roman"></font></font> </p><p style="margin:0in 0in 0pt" class="MsoNormal"><font size="3"><font face="Times New Roman"></font></font> </p>
<font size="3" face="Times New Roman">
</font><font size="3" face="Times New Roman">
</font><p style="margin:0in 0in 0pt" class="MsoNormal"><font size="3"><font face="Times New Roman">- Bob</font></font></p><font size="3" face="Times New Roman">
</font></div><div>________________________________________________________________________________________________</div><div> </div><div> </div><div>Jaigath,<br><br>Karen is right on. Lower window U-values and additional insulation in walls and roofs can cause a net energy increase in buildings with high internal heat gains. If you look at the month-by-month consumption, you may see that the "better" envelope helps out in winter and summer, but hurts in spring and fall. The overall net effect over the year is sometimes negative.<br>
<br>When the air outside is cooler than inside, then some of the internal heat can get out of the building through the envelope. A more insulated envelope slows the heat escaping through the envelope, so more of the heat has to get out of the building through the HVAC system, resulting in more cooling energy. If there is an economizer ("free cooling"), the effect is not as severe the net effect of more insulation could be positive.<br>
<br>________________________________<br>Keith Swartz, P.E., LEED AP<br><br>Energy Engineer / Senior Project Manager<br>Energy Center of Wisconsin<br>455 Science Drive, Suite 200, Madison, WI 53711<br>Phone: 608.238.8276 x123<br>
Fax: 608.238.0523<br><br>The Buildings Team<br>Design decisions through energy, economics and emissions analysis.<br><a href="http://www.ecw.org/Buildings">www.ecw.org/Buildings</a><<a href="http://www.ecw.org/Buildings">http://www.ecw.org/Buildings</a>><br>
<br>Energy Center University<br>Your gateway to sustainable design training and online education programs.<br><a href="http://www.ecw.org/university/">www.ecw.org/university/</a><<a href="http://www.ecw.org/university/">http://www.ecw.org/university/</a>><br>
From: Karen Walkerman [mailto:<a href="http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org">kwalkerman at gmail.com</a>]<br>Sent: Friday, September 24, 2010 6:15 AM<br>To: Jaigath Chandraprakash<br>Cc: <a href="http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org">bldg-sim at lists.onebuilding.org</a><br>
Subject: Re: [Bldg-sim] Unusual Result<br><br>If most of your cooling loads come from internal loads as you said, then having windows with a higher U-value allows the building to lose heat to the outside any time it is cooler outside than inside. If you look at ASHRAE 90.1, the requirements for windows changes dramatically as you move from colder to warmer zones. In warmer zones, the allowed U-value is higher, but the SHGC is lower.<br>
<br>Also, it is usually good to verify that this is actually the case, often installed equipment runs only a fraction of the day, or at a fraction of the peak energy use. If your internal loads are not actually as high as you are modeling, this could change things.<br>
<br>Lastly, does the building have an economizer? This may make sense for this particular project.<br><br>--<br>Karen<br>On Fri, Sep 24, 2010 at 5:59 AM, Jaigath Chandraprakash <<a href="http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org">cjaigath at yahoo.com</a><mailto:<a href="http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org">cjaigath at yahoo.com</a>>> wrote:<br>
The project I am working on is an office building that operates 20 hrs per day with most of the loads occuring at night and low occupancy on daytime. It is a cooled by a DX roof unit and has a very high internal load. No heating equipment is required because the building is in Climate 1. I was surprised that when I changed my window U-value from 0.3 to 0.7 I got less cooling consumption. I always thought that getting low u-value will give me less coling consumption. Can somebody tell me why I am getting less cooling when I use a higher window U-value?<br>
<br>Thanks,<br><br>Jaigath<br><br><br> </div>