<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:st1="urn:schemas-microsoft-com:office:smarttags" 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 11 (filtered medium)">
<!--[if !mso]>
<style>
v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style>
<![endif]--><o:SmartTagType
namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="PostalCode"/>
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="State"/>
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="City"/>
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="Street"/>
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="address"/>
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="place"/>
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="PersonName"/>
<!--[if !mso]>
<style>
st1\:*{behavior:url(#default#ieooui) }
</style>
<![endif]-->
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Shruti;
panose-1:2 0 5 0 0 0 0 0 0 0;}
@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:12.0pt;
font-family:"Times New Roman";
color:black;}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:purple;
text-decoration:underline;}
p.MsoAutoSig, li.MsoAutoSig, div.MsoAutoSig
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";
color:black;}
pre
{margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";
color:black;}
span.EmailStyle18
{mso-style-type:personal;
font-family:Arial;
color:windowtext;}
span.EmailStyle20
{mso-style-type:personal-reply;
font-family:Arial;
color:navy;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;}
div.Section1
{page:Section1;}
-->
</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 bgcolor=white lang=EN-US link=blue vlink=purple>
<div class=Section1>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The current controls are when outside air is
below 55F the cooling coil shuts down, there is no supplemental cooling only
lake water. Therefore the outside air and return air must modulate to
maintain 55F supply air temp. With 300 kW of internal gain and 40000 CFM supply
airflow, SS-F shows up to 200F in the space at minimum outside air below
55F. We considered letting the lake water coil run at all temperatures though
don’t want to risk freezing the coil. I understand that if we run
the coil in the winter time and just return air it would probably save on fan
energy. The coil is probably efficient enough and the thought is the main
water line will have enough pressure to branch off and circulate through the coil
loop without additional pumping at all times.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Considering the current design strategy, I
think the only way to accuracy model the OA and RA modulation is to schedule it
in the min-OA schedule. I have set a min-supply-T so the software should
use that as a minimum supply air temperature but I notice that when economizing,
at least with no low limit, the min-supply-T entry gets thrown into the garbage
(yet we still get the warning). Is there any way to program it in using
expressions? Not sure which entry though, maybe min-air-schedule?
Above 55F, since 100% OA is used, the cooling coil is only used when lake water
temp is below outside air temp. There is no way to model this however, except
fiddling with the cool-control range, which is entirely inaccurate. I
think the economizer should be integrated with coil because they are both used simultaneously,
at least in the current control scheme. You might be able to get away
with the delta T just using return air, I haven’t done the calc though.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The model is pretty much done, I think,
and I was hoping to get some feedback from the board on this warning.
Something that I am not seeing? <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Thank you.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Kevin<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
color=black face="Times New Roman"><span style='font-size:12.0pt;color:windowtext'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;color:windowtext;font-weight:bold'>From:</span></font></b><font
size=2 color=black face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;
color:windowtext'> Bruce Easterbrook [mailto:bruce5@bellnet.ca] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Monday, August 02, 2010 4:47
PM<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">Kevin
Kyte</st1:PersonName><br>
<b><span style='font-weight:bold'>Cc:</span></b> <st1:PersonName w:st="on">'eQUEST
Users List'</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Equest-users] an
inadequate cooling capability warning</span></font><font color=black><span
style='color:windowtext'><o:p></o:p></span></font></p>
</div>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'> I think your control strategy is
not right or you are misinterpreting how equest works. You say your room
requires cooling at all times of the year and you want to keep your maximum
temperature below 104F. You have selected 90F as your control point which
is the setting of your room t-stat. Your 55F temperature only matters if
you have potentially freezing temperatures in the winter because you have a
water coil which you don't want to freeze. Below 55 your economizer is
shut off and you should be on minimum fresh air which with no personnel in the
pump room should be at .06 cfm/SF, you will be almost at 100% return air.
You should have a differential temperature or enthalpy controller to control
the economizer. Your system will remain like this, considering std equest
defaults until the room temperature reaches 92 F. If the outside air
temperature is above 55 the system will use the economizer to control the
temperature. If that fails it will use the cooling coil. You don't
want both the economizer and the cooling cool running at the same time.
Basically you don't want to use water pumping energy if you don't have to as it
is additional energy on top of the fan. Practically you could have 2
temperature controllers controlling part of the same air stream and the system
will hunt. The only other variable here is the water temperature in the
summer. Basically your peak heat generation in the pump room and your
peak water temperature in the summer will set your system CFM, coil size, coil
flow, pump size. This is a basic explanation, there are more things to
play with to fine tune the system further.<br>
Bruce Easterbrook P.Eng.<br>
Abode Engineering<br>
<br>
On 02/08/2010 03:09 PM, <st1:PersonName w:st="on">Kevin Kyte</st1:PersonName>
wrote: <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'><u1:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="PostalCode"><u1:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="State"><u1:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="City"><u1:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="Street"><u1:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="address"><u1:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place">I
have been struggling with this scenario. A pump room does not need to
exceed 104F. <st1:place u2:st="on"><st1:place w:st="on">Lake</st1:place></st1:place>
water is used for cooling. The room is expected to contain internal loads
requiring cooling at almost all times. Below 55F the OA and RA modulate
to provide 55F supply air. Above 55F, 100% OA and the cooling coil turns
on. I have the cooling Tstat set to 90F and cooling coil available at
55F. I am unsure how to even model Below 55F except for economizing which
is not really exact but when I set the economizing low limit to 55F I get 200F
in the space. I have set economizing to 90F integrated with the coil and
no low limit. The cooling coil is rarely used and not needed in its full
capacity yet I am getting inadequate cooling warnings. <u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>The Min-Supply-T is set to 55F because supply should
not be less than this and hourly reports show acceptable supply temperatures
into the mid 70s (I don’t know if this is acceptable to the
program?) I am not using a lake water chiller because I am not trying to
use the same coil temperature. I am using a simple packaged single zone
with the cool-control range set to max and EIR zero’d because there is
enough force off the main header to not need any pumping through the loop.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>This is only for energy code compliance and I need an
explanation on the warnings. Other than stating several obvious
limitations I don’t really understand why this warning is occurring.
Does anyone have suggestions on how I may model this system?<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>I understand that electronic files would help and I
will work on that.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'>Thank you.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoAutoSig><st1:PersonName w:st="on"><font size=3 color=black
face="Times New Roman"><span style='font-size:12.0pt'>Kevin Kyte</span></font></st1:PersonName>,
<font size=2><span style='font-size:10.0pt'>LEED</span></font><sup><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> </span></font></sup><sup><font
size=2><span style='font-size:10.0pt'>®</span></font></sup><font size=2><span
style='font-size:10.0pt'> AP<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><st1:place u2:st="on"><st1:place w:st="on"><b><font size=3
color=black face="Times New Roman"><span style='font-size:12.0pt;font-weight:
bold'>Watts</span></font></b></st1:place></st1:place><b><span
style='font-weight:bold'> Architecture & Engineering, P.C.<u1:p></u1:p></span></b><o:p></o:p></p>
<p class=MsoNormal><st1:street u2:st="on"><st1:address u2:st="on"><st1:Street
w:st="on"><st1:address w:st="on"><font size=2 color=black face=Shruti><span
style='font-size:10.5pt;font-family:Shruti'>95 Perry Street, Suite 300</span></font></st1:address></st1:Street></st1:address></st1:street><o:p></o:p></p>
<u1:p></u1:p>
<p class=MsoNormal><st1:place u2:st="on"><st1:city u2:st="on"><st1:place w:st="on"><st1:City
w:st="on"><font size=2 color=black face=Shruti><span style='font-size:10.5pt;
font-family:Shruti'>Buffalo</span></font></st1:City><font size=2 face=Shruti><span
style='font-size:10.5pt;font-family:Shruti'></st1:city>, <st1:state u2:st="on"><st1:State
w:st="on">NY</st1:state></st1:State> <st1:postalcode u2:st="on"><st1:PostalCode
w:st="on">14203</st1:postalcode></st1:PostalCode></span></font></st1:place></st1:place><o:p></o:p></p>
<u1:p></u1:p>
<p class=MsoNormal><font size=2 color=black face=Shruti><span style='font-size:
10.5pt;font-family:Shruti'>p: 716.206.5174<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Shruti><span style='font-size:
10.5pt;font-family:Shruti'>f.: 716.206.5199<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face="Times New Roman"><span
style='font-size:11.0pt'>e: <a href="mailto:kkyte@watts-ae.com"
moz-do-not-send=true>kkyte@watts-ae.com</a><u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face="Times New Roman"><span
style='font-size:11.0pt'><a href="http://www.watts-ae.com/"
moz-do-not-send=true>http://www.watts-ae.com</a><u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face="Times New Roman"><span
style='font-size:11.0pt'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'><u1:p> </u1:p><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'><u1:p> </u1:p><o:p></o:p></span></font></p>
<pre wrap=""><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fieldset class="mimeAttachmentHeader"></fieldset><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'>_______________________________________________<o:p></o:p></span></font></pre><pre><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'>Equest-users mailing list<o:p></o:p></span></font></pre><pre><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'><a
href="http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org">http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org</a><o:p></o:p></span></font></pre><pre><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'>To unsubscribe from this mailing list send a blank message to <a
href="mailto:EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG">EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG</a><o:p></o:p></span></font></pre><pre><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt'> <o:p></o:p></span></font></pre></div>
</u1:smarttagtype></u1:smarttagtype></u1:smarttagtype></u1:smarttagtype></u1:smarttagtype></u1:smarttagtype>
</body>
</html>