<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 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
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.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0in;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma",sans-serif;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0in;
margin-right:0in;
margin-bottom:0in;
margin-left:.5in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma",sans-serif;}
span.EmailStyle21
{mso-style-type:personal;
font-family:"Calibri",sans-serif;
color:windowtext;}
span.EmailStyle22
{mso-style-type:personal;
font-family:"Calibri",sans-serif;
color:windowtext;}
span.EmailStyle23
{mso-style-type:personal;
font-family:"Calibri",sans-serif;
color:#1F497D;}
span.EmailStyle25
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:50270868;
mso-list-template-ids:-464486952;}
@list l0:level1
{mso-level-tab-stop:.5in;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level2
{mso-level-tab-stop:1.0in;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level3
{mso-level-tab-stop:1.5in;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level4
{mso-level-tab-stop:2.0in;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level5
{mso-level-tab-stop:2.5in;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level6
{mso-level-tab-stop:3.0in;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level7
{mso-level-tab-stop:3.5in;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level8
{mso-level-tab-stop:4.0in;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level9
{mso-level-tab-stop:4.5in;
mso-level-number-position:left;
text-indent:-.25in;}
@list l1
{mso-list-id:1982735088;
mso-list-template-ids:-160288084;}
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
--></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">My only other advice is to identify which zones are requiring the extra cooling in the summer that the rest of the zones don’t need. This is the cause of reheat. Try setting all the process loads to 0.0 and if that fixes the problem, start
adding the process loads back in a bit at a time.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I would also look at the hourly reports and see if you can identify the time of day the reheat occurs in the summer months. This might give you a clue as to the problem.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black">Kathryn Kerns</span></b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-family:"Arial",sans-serif;color:#1F497D">Systems Specialist</span></b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;font-variant:small-caps;color:teal">BCE</span></b><b><span style="font-size:10.0pt;font-family:"Times New Roman",serif;font-variant:small-caps;color:teal">
</span></b><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;font-variant:small-caps;color:teal">Engineers, Inc.<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:9.0pt;font-family:"Times New Roman",serif;color:black">| Ph: 253.922.0446 | Fx: 253.922.0896 |</span></b><span style="font-size:7.0pt;font-family:"Times New Roman",serif;color:black">
<o:p></o:p></span></p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b>From:</b> Alireza Mohammadzadeh [mailto:ali.mo@rpeng.ca] <br>
<b>Sent:</b> Monday, December 18, 2017 2:13 PM<br>
<b>To:</b> Kathryn Kerns <kathryn.kerns@bceengineers.com>; equest-users@onebuilding.org<br>
<b>Subject:</b> RE: VAV with Reheat in Summer<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Thanks for the reply. Yeah I already set the cooling control to Warmest in the model. If I change it back to “reset” (default in equest for VAV) my reheat load will be significantly higher.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Even with warmest in cool control, I have a lot of reheat in summer shoulder which doesn’t make sense to me.<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">Ali<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<div>
<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"> Kathryn Kerns [<a href="mailto:kathryn.kerns@bceengineers.com">mailto:kathryn.kerns@bceengineers.com</a>]
<br>
<b>Sent:</b> Monday, December 18, 2017 1:22 PM<br>
<b>To:</b> Alireza Mohammadzadeh; <a href="mailto:equest-users@onebuilding.org">equest-users@onebuilding.org</a><br>
<b>Subject:</b> RE: VAV with Reheat in Summer<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I was having the same issues and had difficulty explaining how the PVAV system works. After a lot of trial and error, I discovered one thing that affects the VAV reheat in the warmer months and one thing that affects the amount of mechanical
cooling in the cooler months.<o:p></o:p></p>
<ol style="margin-top:0in" start="1" type="1">
<li class="MsoNormal" style="mso-list:l0 level1 lfo3">The “Cooling Control” variable under the Cooling Tab affects the amount of reheat that occurs in the summer months. There is a great deal of difference in the amount of reheat if you use the ASHRAE baseline
5 delta F reset based on outside air temperature and using the “Warmest” option. Try it, and you will see.<o:p></o:p></li><li class="MsoNormal" style="mso-list:l0 level1 lfo3">The “Economizer Low Limit” function located under the Outdoor Air tab, if available, usually shows up as 45 F. Lowering this down to 35 F will reduce the amount of mechanical cooling used in the cooler season.<o:p></o:p></li></ol>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hope this helps.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black">Kathryn Kerns</span></b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-family:"Arial",sans-serif;color:#1F497D">Systems Specialist</span></b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;font-variant:small-caps;color:teal">BCE</span></b><b><span style="font-size:10.0pt;font-family:"Times New Roman",serif;font-variant:small-caps;color:teal">
</span></b><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;font-variant:small-caps;color:teal">Engineers, Inc.<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:9.0pt;font-family:"Times New Roman",serif;color:black">| Ph: 253.922.0446 | Fx: 253.922.0896 |</span></b><span style="font-size:7.0pt;font-family:"Times New Roman",serif;color:black">
<o:p></o:p></span></p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b>From:</b> Equest-users [<a href="mailto:equest-users-bounces@lists.onebuilding.org">mailto:equest-users-bounces@lists.onebuilding.org</a>]
<b>On Behalf Of </b>Alireza Mohammadzadeh via Equest-users<br>
<b>Sent:</b> Monday, December 18, 2017 12:41 PM<br>
<b>To:</b> <a href="mailto:equest-users@onebuilding.org">equest-users@onebuilding.org</a><br>
<b>Subject:</b> [Equest-users] VAV with Reheat in Summer<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi eQUEST users,<o:p></o:p></p>
<p class="MsoNormal">I’m modelling a building that uses VAV with reheat for perimeter and interior zones. The min flow ratio at zone level can’t be less than 1, and I set the design flow to match our design.<o:p></o:p></p>
<p class="MsoNormal">I get a lot of reheat in summer shoulder, and when I look at the hourly report it seems like my central coil is cooling down the intake and zone coil reheats it. I only have one thermal zone for each VAV at this stage, and I’m sure that
summer reheat is not because of humidity control.<o:p></o:p></p>
<p class="MsoNormal">Any suggestion how I can get rid of the large should season reheat?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks in advanced <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">P.S., I attached INP and PD2 files.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Ali Mo, EIT<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</body>
</html>