<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:"Century Gothic";
panose-1:2 11 5 2 2 2 2 2 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0cm;
margin-right:0cm;
margin-bottom:0cm;
margin-left:36.0pt;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:2.0cm 42.5pt 2.0cm 3.0cm;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:2128504537;
mso-list-type:hybrid;
mso-list-template-ids:-796895624 -1300974766 67698713 67698715 67698703 67698713 67698715 67698703 67698713 67698715;}
@list l0:level1
{mso-level-text:%1-;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level2
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level3
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level4
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level5
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level6
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level7
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level8
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level9
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
ol
{margin-bottom:0cm;}
ul
{margin-bottom:0cm;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal">Dear All,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I got two questions about exhaust fan modeling according to ASHRAE 90.1G-2010, clarifications from experience people would be great;<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">1-<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Proposed system has an exhaust fan, hence I`ll model exhaust fan for 7. VAV with Reheat system as well.<o:p></o:p></p>
<p class="MsoListParagraph">G3.1.2.9.1 says that I should model exhaust fan size as 90% of supply fan. Fair enough, peak flow rate from exhaust will be 90% of VAV peak supply, so there is positive pressure in baseline design zones.
<o:p></o:p></p>
<p class="MsoListParagraph"><o:p> </o:p></p>
<p class="MsoListParagraph">Further, G3.1.2.10.1 says that peak fan power should be split between supply and exhaust in the same proportion as proposed design. For example, my proposed design got 1000 CFM for supply and 1000 CFM for exhaust, so I`ll split “Peak
Fan Power Consumption” 50% on baseline design as well.<o:p></o:p></p>
<p class="MsoListParagraph">Finally I`ll model VAV <b>Supply</b> Fan curve as mentioned in G3.1.3.15.<o:p></o:p></p>
<p class="MsoListParagraph"><o:p> </o:p></p>
<p class="MsoListParagraph">However, here is my real question: What about efficiency curve of the exhaust fan? Appendix G doesn`t say anything about this issue. It only says that (G3.1.2.1) efficiency of HVAC equipment should be modeled as minimum as shown
on section 6.4. Section 6.4 doesn`t say anything about Exhaust Fans.<o:p></o:p></p>
<p class="MsoListParagraph"><o:p> </o:p></p>
<p class="MsoListParagraph">So that means I can arrange efficiency curve of the exhaust fan in baseline however I want? This kinda opens up the possibility of gaming the system, one can see where exhaust fan will usually work and set the efficiency very low
at that point of the curve, hence higher kWh consumption for the baseline system.<o:p></o:p></p>
<p class="MsoListParagraph"><o:p> </o:p></p>
<p class="MsoListParagraph">Could someone experience clarify what should be the efficiency curve of Exhaust Fans according to ASHRAE 90.1G 2010 edition?<o:p></o:p></p>
<p class="MsoListParagraph"><o:p> </o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">2-<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]> As far as I understood, ASHRAE 90.1G says that exhaust fans shouldn`t be modeled for spaces where no supply fan exists. Or better put, if HVAC system serving the zone has no supply fan, then you cannot model exhaust fan.<o:p></o:p></p>
<p class="MsoListParagraph">This seems extremely unfair for large scale projects where garage exhaust fans, toilet exhaust fans are considerably large.<o:p></o:p></p>
<p class="MsoListParagraph">Has any of you tried to model garage and toilet fans in your baseline model and pass through LEED review? What is the best way to follow if your proposed system got garage exhaust and toilet exhaust fans? I really want to model those
in baseline as well because it will affect my energy efficiency rating.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Century Gothic","sans-serif";color:black">Kind regards,</span>
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<table class="MsoNormalTable" border="0" cellspacing="0" cellpadding="0" width="466" style="width:233.05pt">
<tbody>
<tr>
<td style="padding:0cm 0cm 0cm 0cm">
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#58595B">Ismail Volkan Ozdemir</span></b><span style="font-size:12.0pt;font-family:"Times New Roman","serif"">
</span><b><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#58595B"><o:p></o:p></span></b></p>
<p class="MsoNormal"><i><span style="font-size:8.0pt;font-family:"Arial","sans-serif";color:#58595B">Mechanical Engineer, LEED AP BD+C</span></i><o:p></o:p></p>
</td>
</tr>
</tbody>
</table>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<br>
<hr>
<font face="Arial" color="Gray" size="2"><br>
The information contained in this e-mail (including any attachments) is confidential.<br>
It must not be disclosed to any person without written authority of Renaissance Construction Ltd.<br>
If you are not the intended recipient, please delete it from your system immediately<br>
<br>
www.rencons.com<br>
</font>
</body>
</html>