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<div class=Section1>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Fellow Modelers,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I’ve received a comment regarding my response last week on how
to model CHW pumps for App. G. Specifically, item 7 (see below) and how the 22 W/gpm
is defined for a primary secondary configuration. Section G3.1.3.10 can be interpreted
(at least) two different ways.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>First, Section G3.1.3.10 Chilled-Water Pumps (Systems 7 and 8)<o:p></o:p></span></p>
<p class=MsoNormal style='mso-margin-top-alt:0in;margin-right:203.25pt;
margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt'><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>“The
baseline design pump power shall be 22 W/gpm. Chilled-water systems with
a cooling capacity of 300 tons or more shall be modeled as primary/secondary
systems with variable-speed drives on the secondary pumping loop.
Chilled-water pumps in systems serving less than 300 tons cooling capacity
shall be modeled as primary/secondary systems with secondary pump riding the
pump curve.”<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>The question: <o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>Should each primary and
secondary pump be sized for 22 W/gpm OR should this “design pump power” be
divided up (in some way) between the primary and secondary pumps?<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Position A:<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>If the 22 W/gpm should be the
TOTAL pumping power, there is no guidance on how to divvy up this requirement
and the constant volume primary pumps could be sized for 20 W/gpm and the
secondary (VSD or riding pump curve) can be allotted 2 W/gpm. This would
maximize the pump energy in the baseline model.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Position B:<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>Sizing each primary pump and
secondary pump to 22 W/gpm will over-estimate the baseline pump energy
(VSD or riding pump curve) and this is not the intent of 90.1. The “design
pump power” of 22 W/gpm is the same requirement as Section 11 (ECB method) just
with a different pumping configuration.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>How do you interpret (and model) 90.1 App. G chilled-water pump power
requirement of 22 W/gpm? (Your interpretation doesn’t necessarily have to
be one of the positions above.)<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thanks,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>John<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:8.5pt;font-family:"Arial","sans-serif";
color:gray'>John T. Forester, P.E., LEED AP, Mechanical Design Engineer </span><b><span
style='font-size:8.5pt;font-family:"Arial","sans-serif";color:#0000A0'>I BVH
Integrated Services I</span></b><b><span style='font-size:8.5pt;font-family:
"Arial","sans-serif";color:black'> </span></b><span style='font-size:8.5pt;
font-family:"Arial","sans-serif";color:gray'>617.658.9008 tel </span><b><span
style='font-size:8.5pt;font-family:"Arial","sans-serif";color:#0000A0'>I</span></b><b><span
style='font-size:8.5pt;font-family:"Arial","sans-serif";color:gray'> </span></b><span
style='font-size:8.5pt;font-family:"Arial","sans-serif";color:gray'>617.244.3753
fax</span><span style='font-size:8.5pt;font-family:"Arial","sans-serif";
color:#0000A0'> </span><b><span style='font-size:8.5pt;font-family:"Arial","sans-serif";
color:#0000A0'>I</span></b><b><span style='font-size:8.5pt;font-family:"Arial","sans-serif";
color:gray'> </span></b><span style='font-size:8.5pt;font-family:"Arial","sans-serif";
color:gray'>One Gateway Center Suite 506, Newton MA 02458 </span><b><span
style='font-size:8.5pt;font-family:"Arial","sans-serif";color:#0000A0'>I <a
href="http://www.bvhis.com">www.bvhis.com</a> I Hartford ● New Haven
● Boston</span></b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
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-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-family:"Tahoma","sans-serif"'>
equest-users-bounces@lists.onebuilding.org
[mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>John T.
Forester<br>
<b>Sent:</b> Friday, November 12, 2010 5:47 PM<br>
<b>To:</b> 'Smith, Michael'<br>
<b>Cc:</b> equest-users@lists.onebuilding.org<br>
<b>Subject:</b> Re: [Equest-users] Baseline Chilled Water Loop<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Hi Michael,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I think I can answer your App G question.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>First, in the context of 90.1, “variable flow” does not
necessarily mean variable speed. It just means riding the pump curve with
a bypass to minimize pumping pressure drops through the loop during part-load
operation.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><u><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>App. G Chilled Water Modeling <=300 tons<o:p></o:p></span></u></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span
style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Create a chilled water circulation loop and name it something
like “Pri CHW Loop.”<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span
style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Create another chilled water circulation loop and name it
something like “Sec CHW Loop.”<o:p></o:p></span></p>
<p class=MsoListParagraph style='margin-left:1.0in;text-indent:-.25in;
mso-list:l0 level2 lfo2'><![if !supportLists]><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>a.<span
style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Change
the Loop Sub-type of this loop to Secondary and choose “Pri CHW Loop” as the
primary loop.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span
style='mso-list:Ignore'>3.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Create a circulation pump and name it something like “Sec CHW
Pump.”<o:p></o:p></span></p>
<p class=MsoListParagraph style='margin-left:1.0in;text-indent:-.25in;
mso-list:l0 level2 lfo2'><![if !supportLists]><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>a.<span
style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Set
this pump as variable speed. I believe you are allowed to set the minimum
speed to 50% for App. G. (someone here on the list can correct me on this if
I’m wrong).<o:p></o:p></span></p>
<p class=MsoListParagraph style='margin-left:1.0in;text-indent:-.25in;
mso-list:l0 level2 lfo2'><![if !supportLists]><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>b.<span
style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>By
default, the valve on this loop is three-way and will circulate water directly
back to the primary loop as long as there are two-way valves at your terminal
units (AHU coils, FCUs, etc).<o:p></o:p></span></p>
<p class=MsoListParagraph style='margin-left:1.0in;text-indent:-.25in;
mso-list:l0 level2 lfo2'><![if !supportLists]><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>c.<span
style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Attach
this pump to the Sec CHW Loop.<o:p></o:p></span></p>
<p class=MsoListParagraph style='margin-left:1.0in;text-indent:-.25in;
mso-list:l0 level2 lfo2'><![if !supportLists]><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>d.<span
style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Change
the loop head sensor location to “at coils.”<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span
style='mso-list:Ignore'>4.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Create a condenser water loop and CW pump and attach the pump to
the loop.<o:p></o:p></span></p>
<p class=MsoListParagraph style='margin-left:1.0in;text-indent:-.25in;
mso-list:l0 level2 lfo2'><![if !supportLists]><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>a.<span
style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Also
create an open tower heat rejection device and attach it to your condenser
water loop.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span
style='mso-list:Ignore'>5.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Create 1 primary chilled water pump per chiller. They
won’t be attached to anything yet and will be at the bottom of the component
tree.<o:p></o:p></span></p>
<p class=MsoListParagraph style='margin-left:1.0in;text-indent:-.25in;
mso-list:l0 level2 lfo2'><![if !supportLists]><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>a.<span
style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The
default for a pump is “One-Speed.” This is fine and the pump will act as
a constant volume pump with the three-way valve on the secondary loop.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span
style='mso-list:Ignore'>6.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Create a water-cooled chiller and choose the “Pri CHW Loop 1”
and “water-cooled.”<o:p></o:p></span></p>
<p class=MsoListParagraph style='margin-left:1.0in;text-indent:-.25in;
mso-list:l0 level2 lfo2'><![if !supportLists]><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>a.<span
style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Since
there is no pump attached to the primary loop, you will be required to select a
pump for the chiller.<o:p></o:p></span></p>
<p class=MsoListParagraph style='margin-left:1.0in;text-indent:-.25in;
mso-list:l0 level2 lfo2'><![if !supportLists]><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>b.<span
style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>You
will also be required to select the Condenser water loop<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span
style='mso-list:Ignore'>7.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Now what you have to do is size your pumps so the total pump
energy is 22 W/pm. You will want to do something like 4-5 W/gpm for each
primary pump and use the remaining for the secondary pump.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>This system is primary/secondary with constant flow through each
chiller and variable speed/variable flow through the secondary loop.
Since each chiller has a pump directly attached to it, each primary pump will
automatically cycle on and off with the chillers.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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style='font-size:8.5pt;font-family:"Arial","sans-serif";color:gray'>617.244.3753
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font-family:"Arial","sans-serif";color:gray'>One Gateway Center Suite 506,
Newton MA 02458 </span><b><span style='font-size:8.5pt;font-family:"Arial","sans-serif";
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<p class=MsoNormal><b><span style='font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-family:"Tahoma","sans-serif"'>
equest-users-bounces@lists.onebuilding.org
[mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Smith,
Michael<br>
<b>Sent:</b> Friday, November 12, 2010 3:55 PM<br>
<b>To:</b> equest-users@lists.onebuilding.org<br>
<b>Subject:</b> [Equest-users] Baseline Chilled Water Loop<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Everyone,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I have a question regarding the baseline chilled water loop.
<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>ASHRAE 90.1 2007 Section G3.1.3.10 states that for large
chilled water systems serving baseline systems 7 and 8 that are greater than
300 tons the loop “shall be modeled as primary/secondary with variable speed
drives on the secondary pumping loop.”<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>The following section, G3.1.3.11 further goes on to say that
“each chiller shall be modeled with separate…chilled water pumps interlocked to
operate with the associated chiller.”<o:p></o:p></p>
<p class=MsoNormal style='margin-top:12.0pt'>As clarification, does this mean
three sets of pumps are required, or just two? Are the “primary” loop pumps
specified as the chiller pumps? <o:p></o:p></p>
<p class=MsoNormal style='margin-top:12.0pt'>Two reasons why I am confused.
Firstly, the Chapter 11 baseline chilled water loop is supposed to be simulated
as primary-only variable flow, but still has the similar requirement for
interlocked chiller pumps. That would be two sets of pumps. Adding a
“secondary” loop actually adds a third set of pumps. <o:p></o:p></p>
<p class=MsoNormal style='margin-top:12.0pt'>The second reason why I am
confused is that the <a
href="http://www.energydesignresources.com/Portals/0/documents/DesignGuidelines/EDR_DesignGuidelines_%20HVAC_Simulation.pdf">Simulation
Guidebook</a> prepared for Pacific Gas and Electric (same affiliation as
CoolTools) has a visual of how to simulate “primary/secondary” loops on page
52, but they do not include chiller pumps in their image of the eQUEST
component tree. <o:p></o:p></p>
<p class=MsoNormal style='margin-top:12.0pt'>I can’t understand why three sets
of pumps would be required. I supposed a follow up question may be if the 22
watts/gpm is inclusive of all three sets of pumps. Hopefully someone can
clarify! I appreciate your help. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> </span><span
style='color:#002060'><o:p></o:p></span></p>
<p class=MsoNormal><b><span lang=EN-GB style='font-family:"Arial","sans-serif";
color:#333399'>Michael J. Smith, EIT, LEED</span></b><sup><span
style='font-family:"Arial","sans-serif";color:#333399'>® </span></sup><b><span
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