<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 12 (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]-->
<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;}
@font-face
{font-family:"Franklin Gothic Medium";
panose-1:2 11 6 3 2 1 2 2 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";}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
-->
</style>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="2050" />
</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>I am working on a LEED model for a fully designed building.
The model attempts to incorporate a ground-source heat pump system (modeled as
a Lake/Well loop with temp schedule) with water-to-water heat pumps (chiller
type = heat pump) serving a dual temp loop going to active chilled beam (induction
unit system) zone conditioning. Zones on this system have envelope loads
covered by baseboard heaters on a separate boiler loop. The baseboard loop is
scheduled to be available from September through May, while the dual temp loop
is set to “snap” between heat/cool at 58<sup>o</sup>F OA. The
design intention is for the water-to-water heat pumps to provide all outside
air conditioning for this system – first tempering to neutral at the
system level, and then further conditioning at the zone level. <o:p></o:p></p>
<p class=MsoNormal><img width=648 height=452 id="_x0000_i1027"
src="cid:image003.jpg@01CC1FB2.766A9D00"><o:p></o:p></p>
<p class=MsoNormal>During much of the winter, even when the building is
occupied and zones are receiving outside air, heat pump operation is very low. GSHP
loop flows are inconsistent day-to-day during most of the winter. When I try
different weather locations, the profile of heat pump operation varies
significantly, but electric heating energy and GSHP loop flow remains low. <o:p></o:p></p>
<p class=MsoNormal>Why do I see erratic heat pump operation and loop flows?<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I realize this is a complex model and not an easy question
to dive into, but I would appreciate it if anyone has any advice from
experience with a similar model. I can attach model files if that would help.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Thanks,<o:p></o:p></p>
<p class=MsoNormal>Eric<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Franklin Gothic Medium","sans-serif"'>Eric
Boxer, EIT<span style='color:#0F243E'> </span><span style='color:green'>|</span><span
style='color:#0F243E'> </span>Pathfinder Engineers & Architects LLP</span></b><span
style='color:#0F243E'><br>
</span><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#0F243E'>Mechanical Engineer</span><span style='font-size:9.0pt;
color:#0F243E'> </span><span style='font-size:9.0pt;color:#0F243E'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;color:#0F243E'><br>
</span><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#0F243E'>134 South Fitzhugh Street</span><span style='font-size:9.0pt;
color:#0F243E'><br>
</span><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#0F243E'>Rochester, NY 14608</span><span style='font-size:9.0pt;
color:#0F243E'><br>
</span><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#0F243E'>T: (585) 325-6004 <i>ext. 109</i><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#0F243E'>F: (585) 325-6005<o:p></o:p></span></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><img
width=60 height=58 id="Picture_x0020_1" src="cid:image001.png@01CC1FAD.95F61F00">
<img width=56 height=58 id="Picture_x0020_2"
src="cid:image002.png@01CC1FAD.95F61F00"><span style='font-size:9.0pt;
font-family:"Arial","sans-serif";color:#0F243E'><o:p></o:p></span></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
style='font-size:9.0pt;font-family:"Arial","sans-serif";color:#0F243E'><a
href="mailto:hkashtan@pathfinder-ea.com"><span style='color:blue'>eboxer@pathfinder-ea.com</span></a></span><span
style='font-size:9.0pt;color:#0F243E'> <br>
</span><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#0F243E'><a href="http://www.pathfinder-ea.com/"><span style='color:blue'>www.pathfinder-ea.com</span></a><o:p></o:p></span></p>
<p class=MsoNormal><o:p> </o:p></p>
</div>
</body>
</html>