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<DIV dir=ltr align=left><FONT face="Trebuchet MS" color=#0000ff size=2><SPAN
class=618572020-01042010>Brett, attached are some example kw/ton curves for
existing chillers on a recent project. Chiller #1 is a 250 ton unit, and
chillers 2 thru 4 are 550 ton units. Chillers 1 and 2 are ~ 15 years old,
and chillers 3 and 4 are newer with better efficiencies. All 4 chillers
are water cooled. The curves show efficiencies with and without Adjustable
Frequency Drives. It's hard to tell the difference between the "w/AFD" and
"w/o AFD" curves, but the "w/AFD" curves have a lower kw/ton except at full
load.</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV align=left><FONT face="Trebuchet MS" size=2>Jim Marsh, PE, LEED
AP</FONT></DIV>
<DIV align=left><FONT face="Trebuchet MS" size=2>SEG, Inc.</FONT></DIV>
<DIV align=left><FONT face="Trebuchet MS" size=2>2550 Walsh Avenue</FONT></DIV>
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<DIV align=left><FONT face="Trebuchet MS" size=2>Santa Clara, CA
95051</FONT></DIV>
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<DIV align=left><FONT face="Trebuchet MS" size=2>Fax: 408 260 8018</FONT></DIV>
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size=2>http://seg-corp.com/</FONT></A></DIV>
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<FONT face=Tahoma size=2><B>From:</B> equest-users-bounces@lists.onebuilding.org
[mailto:equest-users-bounces@lists.onebuilding.org] <B>On Behalf Of </B>Pasha
Korber-Gonzalez<BR><B>Sent:</B> Thursday, April 01, 2010 1:11 PM<BR><B>To:</B>
James Hansen<BR><B>Cc:</B> equest-users@lists.onebuilding.org<BR><B>Subject:</B>
Re: [Equest-users] Chiller ROI - HELP!<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV>Brett,</DIV>
<DIV> </DIV>
<DIV>to get better part load data and efficiency of your proposed chiller
replacement, call your chill sales engineer and ask them to generate a part load
performance report for you in 10% unloading increments, then you can see the
decrease in performance efficiency for each part-load step of the chiller.
Also be sure that you recognize if you are looking at RATED Conditions (which
means chiller performance at ARI standard conditions), or at DESIGN conditions
(which are your project's specified operating conditions--this would account for
part load efficiencies if you were running a 12-or 14 Degree delta-T across your
chiller.)</DIV>
<DIV> </DIV>
<DIV>Before you set up a new performance curve you will need to get this data
supplied from the manufacturer.</DIV>
<DIV> </DIV>
<DIV>Pasha<BR><BR></DIV>
<DIV class=gmail_quote>On Thu, Apr 1, 2010 at 2:01 PM, James Hansen <SPAN
dir=ltr><<A
href="mailto:JHANSEN@ghtltd.com">JHANSEN@ghtltd.com</A>></SPAN> wrote:<BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<DIV lang=EN-US link="blue" vlink="purple">
<DIV>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">KW/ton drops off with
decreasing part load, and since the chiller isn’t always operating at ARI full
load conditions, you can’t just divide total chiller energy consumption (in
KWH) by the total cooling load (in btu) and hope to get anywhere near the full
load rated KW/ton.</SPAN></P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d"></SPAN> </P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">As you go about this ROI
study, make sure that when you are analyzing your proposed chiller
replacement, that you create a custom EIR vs PLR curve based on manufacturer’s
data, otherwise you’re using a default DOE-2 curve that isn’t necessarily
correct.</SPAN></P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d"></SPAN> </P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">Furthermore, to make the study
worthwhile, the existing chiller model really needs to be normalized as best
as possible to actual building operating conditions. You can get away
without doing it for a simple comparison, but it would be more accurate if you
normalized to utility bills.</SPAN></P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d"></SPAN> </P>
<DIV>
<P class=MsoNormal><B><SPAN style="COLOR: teal">GHT
Limited<BR></SPAN></B><B><SPAN><SPAN style="COLOR: black">James
Hansen</SPAN></SPAN></B><B><SPAN style="COLOR: black">, PE, LEED
AP</SPAN></B></P>
<P class=MsoNormal><B><SPAN style="FONT-SIZE: 10pt; COLOR: black">Senior
Associate</SPAN></B><B><SPAN style="COLOR: black"></SPAN></B></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 7.5pt"><SPAN
style="COLOR: black">1010 N. Glebe Rd, Suite 200</SPAN></SPAN><SPAN
style="COLOR: #1f497d"></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 7.5pt"><SPAN
style="COLOR: black">Arlington</SPAN><SPAN style="COLOR: black">, </SPAN><SPAN
style="COLOR: black">VA</SPAN><SPAN style="COLOR: black"> </SPAN><SPAN
style="COLOR: black">22201-4749</SPAN></SPAN><SPAN
style="COLOR: black"></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 7.5pt; COLOR: black">703-338-5754
(Cell)</SPAN><SPAN style="COLOR: black"></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 7.5pt; COLOR: black">703-243-1200
(Office)</SPAN><SPAN style="COLOR: black"></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 7.5pt; COLOR: black">703-276-1376
(Fax)</SPAN><SPAN style="COLOR: black"></SPAN></P>
<P class=MsoNormal><SPAN style="COLOR: teal"><A href="http://www.ghtltd.com/"
target=_blank><SPAN
style="FONT-SIZE: 10pt">www.ghtltd.com</SPAN></A></SPAN></P>
<P class=MsoNormal><B><SPAN style="COLOR: #31849b"></SPAN></B> </P></DIV>
<P class=MsoNormal><SPAN style="COLOR: #1f497d"></SPAN> </P>
<DIV>
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<P class=MsoNormal><B><SPAN style="FONT-SIZE: 10pt">From:</SPAN></B><SPAN
style="FONT-SIZE: 10pt"> <A
href="mailto:equest-users-bounces@lists.onebuilding.org"
target=_blank>equest-users-bounces@lists.onebuilding.org</A> [mailto:<A
href="mailto:equest-users-bounces@lists.onebuilding.org"
target=_blank>equest-users-bounces@lists.onebuilding.org</A>] <B>On Behalf Of
</B>Brett Sanicola<BR><B>Sent:</B> Thursday, April 01, 2010 2:38
PM<BR><B>To:</B> <A href="mailto:equest-users@lists.onebuilding.org"
target=_blank>equest-users@lists.onebuilding.org</A><BR><B>Subject:</B>
[Equest-users] Chiller ROI - HELP!</SPAN></P></DIV></DIV>
<DIV>
<DIV></DIV>
<DIV class=h5>
<P class=MsoNormal> </P>
<P class=MsoNormal>I've been attempting to calculate a simple ROI for a new
250 ton chiller our client wants to install to replace his older
chiller. I ran the simulation for the default "high rise hotel"
construction which, to my luck, is quite similar to the actual building.
The detailed results, however, are not making sense to me. Specifically,
when I look at Equipment Loads and Energy Use for the Chiller, the Elec Use
and Cool Load don't coincide given the default Chiller efficiency of
.67kw/ton. For example they give a Chiller Elec Use of 535453 KWH and a
Cool Load of 3294 MBTU. However, according to my calculations, at
.67KW/TON, 535453 KWH should give me closer to 9590 MBTU. I see most of
the hours are in part load range, but does the efficiency drop off that
dramatically at part load that it would explain the discrepancy? Which
numbers should I base my analysis on, the Cool Load number or the Elec Use
number.</P>
<P class=MsoNormal> </P>
<P class=MsoNormal>Also, on the same page (Equipment Loads and Energy Usage),
it gives me a peak load of 2436 KBTU/HR. However, when I go to the
section titled "Building Peak Load Components" the peak cooling load is
significantly less (1619 KBTU/HR)</P>
<P class=MsoNormal> </P>
<P class=MsoNormal>At this point, I have no idea what any number represents,
since I don’t know how it was calculated.</P>
<P class=MsoNormal> </P>
<P class=MsoNormal>I greatly appreciate any help! Thanks.</P>
<P class=MsoNormal> </P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt">Respectfully,</SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman','serif'"></SPAN> </P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt">Brett Sanicola</SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt">Engineer</SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt">ASB Engineering</SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 10pt">(516)
785-4200</SPAN></P></DIV></DIV></DIV></DIV>
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