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<DIV dir=ltr align=left><SPAN class=765362517-04022008><FONT face=Arial
color=#0000ff size=2>My humble opinion is that you should input as much real
data into eQuest as possible. Apologies to my eQuest creator friends, but
default numbers are not as easily discerned as to their sources.
Obviously, great detail and care was performed in developing the "typical"
buildings, but there appears to be no documentation as to where these curves,
loads, etc emanate fro.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=765362517-04022008><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=765362517-04022008><FONT face=Arial
color=#0000ff size=2>You cannot take an IPLV and extract four coefficients from
it to develop a Base Case chiller curve (it WOULD be nice). But if ASHRAE 90.1
would give us a better guideline as to HOW to make a more accurate curve for the
Base Line to create such a required IPLV.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=765362517-04022008><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=765362517-04022008><FONT face=Arial
color=#0000ff size=2>So REAL (or actual) applies, as i understand it, only to
the Proposed case, where one can indeed can obtain a "real" chiller
curve.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=765362517-04022008><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=765362517-04022008><FONT face=Arial
color=#0000ff size=2>John</FONT></SPAN></DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> bldg-sim-bounces@lists.onebuilding.org
[mailto:bldg-sim-bounces@lists.onebuilding.org] <B>On Behalf Of </B>Robby
Oylear<BR><B>Sent:</B> Monday, February 04, 2008 9:14 AM<BR><B>To:</B>
bldg-sim@lists.onebuilding.org<BR><B>Subject:</B> [Bldg-sim] eQuest Default
f(PLR) Skepticism<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV class=Section1><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Excuse me for reviving an old thread here, but I’ve been having a similar problem to what <st1:City w:st="on"><st1:place w:st="on">Taylor</st1:place></st1:City> had in this thread and I can’t really find the answer in the replies he received. I have been inputting actual chiller performance data for a project that I’m on and the results come out that the proposed building uses much more cooling energy than the baseline. Throughout this project I’ve thought the baseline cooling energy to be too low, especially now when compared to a VSD centrifugal chiller which should have better part load efficiency the baseline out performs it. <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">To get a concept of what a real baseline chiller should look like I asked my local rep to produce data for a fictitious ARI chiller which matches the COP and IPLV required by 90.1. I then compared the EIR-f(PLR) curves of the ARI chiller to the eQUEST default curve and found them to be drastically different. The eQUEST default curve starts at 1, and like <st1:City w:st="on"><st1:place w:st="on">Taylor</st1:place></st1:City> said, decreases almost linearly as the part load decreases. The actual data that I received shows quite the opposite, which is the chiller starts at 1.0 at 100% and at around 70% PLR it begins to increase up until 30% where it reaches a value of 1.5. To me this seems quite more realistic, where the chiller (without a VSD of course) would perform much worse at low part loads. eQUEST defaults actually perform best at part loads of 10% or less. <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">The choice of going with the default curves or with actual data of a 90.1 baseline compliant chiller has a huge impact on the energy use of my building because 40% of my hours are in the 10-15% part load range.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Anyone have any thoughts on this subject?<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE>
<P class=MsoNormal><FONT face="Franklin Gothic Demi" size=3><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Franklin Gothic Demi'">Robby
Oylear</SPAN></FONT><FONT face="Franklin Gothic Demi" size=2><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: 'Franklin Gothic Demi'"><o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><I><FONT face="Times New Roman" size=2><SPAN
style="FONT-SIZE: 10pt; FONT-STYLE: italic">Project
Engineer<o:p></o:p></SPAN></FONT></I></P>
<P class=MsoNormal><FONT face="Times New Roman" size=2><SPAN
style="FONT-SIZE: 10pt">direct: 206.788.4571<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face="Times New Roman" size=2><SPAN
style="FONT-SIZE: 10pt">cell: 206.354.2721</SPAN></FONT><o:p></o:p></P>
<P class=MsoNormal style="MARGIN-BOTTOM: 3pt"><FONT face=Arial size=1><SPAN
style="FONT-SIZE: 8pt; FONT-FAMILY: Arial"><A
title=blocked::http://www.rushingco.com/ href="http://www.rushingco.com/"><FONT
color=black><SPAN style="COLOR: windowtext; TEXT-DECORATION: none"><SPAN
title=blocked::http://www.rushingco.com/>www.rushingco.com</SPAN></SPAN></FONT></A><o:p></o:p></SPAN></FONT></P><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">The original message is attached below:<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">A few more comments regarding boilers:<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">We based the default curve for atmospheric boilers on information received<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">from a <st1:place w:st="on">Northern California</st1:place> manufacturer?s representative. The default<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">atmospheric boiler consumes 45% fuel at 40% part load, so efficiency does<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">deteriorate. At full load, the efficiency is 80%; calculated as (PLR=1.) /<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">(HIR=1.25). At 40% load, the default curve yields an efficiency of 71%;<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">calculated as (PLR=0.40) / (HIR=1.25 * HIRfPLR=0.45). <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">We believe that a 71% efficiency at 40% load is reasonable for a modern<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">atmospheric boiler. The default was based on a packaged water-tube boiler<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">with internal convective recirculation, but performance for other types is<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">expected to be similar. <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">The default atmospheric boiler unloads to 40% part-load ratio, and then<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">starts to cycle on/off; the HIRfPLR curve is valid only for part-load ratios<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">above 40%. The loss during the off-cycle is characterized by the ?standby<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">time?, which is the equivalent full-load time in hours required to keep the<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">boiler hot, if the boiler has no load at all. The default is 0.027 hours,<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">meaning that, at no load, the boiler would have to run about 2 minutes/hour<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">at full load to offset the jacket and flue losses. The documentation<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">describes the use of the standby-time vs. the part-load curve in further<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">detail. At very low loads, efficiency is seriously degraded; by definition<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">the efficiency at 0% load is 0%. You can observe this if you set up an<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">hourly report for the boiler and observe it at very low loads. <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Our experience to date is that manufacturer?s part-load data for boiler<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">performance is quite difficult to obtain. If any of you have well-documented<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">data that deviates significantly from the defaults, we would appreciate<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">hearing from you. As eQUEST/DOE-2 supports a library of equipment, it would<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">be possible to add performance data for various types of boilers to the<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">library.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">For chillers, let me further clarify Kevin's comment regarding the<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">EIRf(PLR,dT) curve. As Kevin explained, the dT term need be developed only<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">for variable-speed centrifugal chillers; it is of quite limited value for<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">constant-speed centrifugals, and of extremely limited value for<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">positive-displacement machines. <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">The discharge/suction temperature differential is closely associated with<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">the discharge/suction pressure differential. If the cooling tower is<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">controlled to a fixed, high setpoint such as 85F, then the chiller impeller<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">may not be able to slow down much at all, even at low loads; the majority of<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">capacity modulation will then be via the inlet vanes rather than speed. This<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">is because the maximum possible pressure rise across the impeller drops off<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">as the square of the impeller speed. Chiller impellers are typically closely<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">matched to the design pressure rise specified by the engineer. If the<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">required pressure rise does not drop off substantially as the load drops,<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">then the impeller must maintain speed to avoid surge.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Data commonly published by manufacturers (and implicit in the IPLV) ASSUMES<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">the condensing temperature drops with load; thereby allowing the impeller<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">speed to drop off. That may not actually be the case in real life! Nor is it<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">true in eQUEST unless you specify a low tower setpoint, or utilize a tower<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">reset scheme. <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">The default EIRf(PLR,dT) curve for variable-speed centrifugals was developed<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">using a manufacturer's proprietary software package that was loaned to us;<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">it password-expired after a short time. To our knowledge, these data cannot<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">be developed from software available to the general engineering community.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">(You need to be able to vary the chilled-water and condensing temperatures<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">independently of the part-load ratio. This is also why IPLV data is<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">worthless for an hourly simulation program; the "condenser relief" is built<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">into the part-load performance.) Let me know if you are aware of any<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">centrifugal chiller manufacturers that make this data generally available.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">This brings to mind another interesting point that perhaps others can<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">respond to. Over the years I have heard unsubstantiated rumors that a<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">multi-impeller chiller, such as a Trane, may have significantly different<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">part-load performance compared to a single-impeller chiller, such as a<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Carrier. Does anybody have information regarding multi-impeller vs.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">single-impeller part-load performance?<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Regards,<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Steven Gates<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">eQUEST Development Team<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">-----Original Message-----<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">From: BLDG-SIM@xxxxxxxx [<A href="mailto:BLDG-SIM@xxxxxxxx">mailto:BLDG-SIM@xxxxxxxx</A>] On Behalf Of Kevin<o:p></o:p></SPAN></FONT></PRE><PRE><st1:City w:st="on"><st1:place w:st="on"><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Madison</SPAN></FONT></st1:place></st1:City><o:p></o:p></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Sent: Friday, October 05, 2007 8:45 AM<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">To: BLDG-SIM@xxxxxxxx<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Cc: BLDG-SIM@xxxxxxxx<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Subject: [BLDG-SIM] eQuest Default f(PLR) Skepticism<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">You are too generous Mike. I should heed my own advice on the <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">documentation. Thanks for clarifying this.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">I also thought and consulted a colleague (thanks Steve) on <st1:City w:st="on"><st1:place w:st="on">Taylor</st1:place></st1:City>'s <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">chiller question:<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">For chillers, the second term in EIRf(PLR,dT) is important only for <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">variable-speed centrifugal chillers. It is of negligible importance in <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">other types of chillers. It is important in variable-speed, because the <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">temperature differential is strongly correlated with the required speed <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">of the impeller. If the dT is high enough, then the impeller may have to <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">run at full speed even at low loads. The DOE-2 default curves are just <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">that, defaults. Some folks find it necessary to create new curves to <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">reflect their specific equipment. Cautions offered<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">* verify the conditions (condenser/evaprator) for efficiencies at lower <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">part loads are the same as for above 50%<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">* make sure the points are normalized around the rating condition<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Sorry for my hasty response.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Kevin Madison<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt"><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">Michael Tillou wrote:<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Actually Kevin didn't get the boiler hourly energy equation quite <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> right. The actual equation is:<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Hourly Boiler Energy = DesignCapacity * HIR * HIRf(plr)<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> The part of this that Kevin didn't explain is that the boiler <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> HIRf(PLR) curve includes the PLR which explains why the curve is <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> nearly linear. The value that the performance curve returns is actually<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> (HIRadj) * PLR<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> HIRadj = the multiplier that indicates how the full load HIR changes <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> with respect to part load. If the boiler efficiency at a given part <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> load goes down, HIRadj > 1. If the boiler efficiency goes up at a <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> given part load HIRadj<1. HIRadj is really the ratio HIR-partload over <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> HIR-fullload.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> PLR = hourly load on the boiler / total capacity of the boiler<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> To create a curve that describes boiler HIR at various part loads you <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> will need to divide the performance curve output at each part load <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> point by the part load value and then multiply by the full load HIR.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> <st1:City w:st="on"><st1:place w:st="on">Taylor</st1:place></st1:City> - You should double check your "custom" chiller curves I'm <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> pretty sure from what you describe they are not correct. The Vol6 -New <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Features user manual does a good job describing how the chiller curves <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> work. I suggest you review this. You can use the Excel function <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> "LINEST" to create the necessary coefficients for a bi-quadratic curve <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> from manufacturers chiller data. Typically you will need to request <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> data for a specific chiller from the chiller rep. The hardest data to <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> get is the chiller capacity data at various CHW/CW temperatures. <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Remember total chiller capacity is different than the rated 100% part <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> load point, most chillers can provide 10-20% extra capacity.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> I have had good experience creating custom chiller curves for DOE2.2 <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> and I think the default curves in eQuest are representative of the <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> various chiller types. Obviously if you are evaluating a specific <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> chiller you should try to create custom curves.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Mike<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> ------------------------------------------------------------------------<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> *From:* BLDG-SIM@xxxxxxxx [<A href="mailto:BLDG-SIM@xxxxxxxx">mailto:BLDG-SIM@xxxxxxxx</A>] *On Behalf Of <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> *Kevin Madison<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> *Sent:* Thursday, October 04, 2007 9:46 PM<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> *To:* BLDG-SIM@xxxxxxxx<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> *Subject:* [BLDG-SIM] eQuest Default f(PLR) Skepticism<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Perhaps it would help to clarify how DOE-2.2 (the simulation engine <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> behind eQUEST) calculates hourly energy input for boilers and chillers.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> For boilers, the hourly energy input is:<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Hourly Energy = Cap(hour) * HIR * HIRf(plr)<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> So while the HIRf(plr) may increase as part load decreases, which is <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> not uncommon for standard atmospheric boilers, the energy use will <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> certainly decrease with plr because the required output of the boiler <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> for the hour decreases.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> For chillers, DOE-2 uses the following relationship to calculate the <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> electricity input to the chiller each hour:<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Caphour = Capacity * CAPf(t1,t2)<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> PLR = Load / Caphour<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> dT = t2 ? t1<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Elechour = Caphour * EIR * EIRf(t1,t2) * EIRf(PLR,dT) / 3413 Btu/kW<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> where<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Caphour hourly capacity, Btuh (this is dependent on condenser and <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> evaporator conditions for that hour)<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Capacity rated capacity, Btuh<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> CAPf(t1,t2) correction to capacity for temperatures, curve CAP-FT<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> t1 leaving chilled-water temperature, °F<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> t2 condenser temperature, °F<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> PLR Part load ratio<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Load Hourly load, Btuh<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> dT Temperature differential across chiller, °F<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Elechour electric input to the chiller, kW<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> EIR rated electric input ratio<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> EIRf(t1,t2) correction to EIR for temperatures, curve EIR-FT<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> EIRf(PLR,dT) correction to EIR for part-load ratio and dT, curve EIR-FPLR<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Again, the primary factor affecting chiller energy use is the cooling <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> capacity needed for that hour. Just because you don't have access to <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> the dual function information doesn't mean you shouldn't be accounting <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> for it in the simulation. Chiller performance is dependent on all <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> operating conditions including load, condenser conditions and <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> evaporator conditions.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> For a more complete discussion on these simulation concepts, refer to <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> the DOE-2 documentation included with the eQUEST installation. Look in <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Dictionary:HVAC Components:Boiler:Boiler Energy Consumption and <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Dictionary:HVAC Components:Chiller:Chiller Energy Consumption.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Kevin Madison<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Madison Engineering PS<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> <st1:place w:st="on"><st1:City w:st="on">Seattle</st1:City> <st1:State w:st="on">WA</st1:State></st1:place><o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> <st1:country-region w:st="on"><st1:place w:st="on">USA</st1:place></st1:country-region><o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">> Taylor Keep wrote:<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> eQuest models boiler and chiller plants with default part load curves <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> that I think may be incorrect. As I understand it, the f(PLR) curves <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> are used as a direct multiplier on the HIR for boilers and EIR for <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> chillers, with full load (1.0 PLR) corresponding to a 1.0 multiplier. <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> If this is true, the f(PLR) curve should increase at part load for <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> atmospheric boilers (atmospheric boilers become somewhat less <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> efficient at part load). The default atmospheric boiler curve <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> decreases almost linearly down to zero! I am having a tough time <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> wrapping my head around this.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> On the chiller side, the default f(PLR) is a bi-quadratic function <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> using both dT and PLR as variables, so it is f(PLR,dT). Since I never <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> have this dual function information in my general chiller selections, <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> I have been using a standard f(PLR) function quoted at a fixed dT <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> from the manufacturer. The curve I get from a McQuay 400-ton chiller <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> selection is quadratic, with decreasing EIR down to 50% load and <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> increasing EIR below 50% load. I seriously doubt that the eQuest <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> default corresponds with this entry because changing the function <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> produces a huge change in performance.<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> Do any of you have any thoughts or suggestions about the accuracy of <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> default f(PLR) curves? Should I scrap my "improved," real curves - <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> they are drastically changing the model performance?!?!<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> <st1:City w:st="on"><st1:place w:st="on">Taylor</st1:place></st1:City><o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> ________________________________________________________<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> Taylor Keep<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> Mechanical, LEED® AP<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> _ _<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> Arup<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> <st1:Street w:st="on"><st1:address w:st="on">901 Market Street Suite 260</st1:address></st1:Street><o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> <st1:place w:st="on"><st1:City w:st="on">San Francisco</st1:City>, <st1:State w:st="on">CA</st1:State> <st1:PostalCode w:st="on">94103</st1:PostalCode></st1:place><o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> tel: 415 946 0279<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> fax: 415 957 9096<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> taylor.keep@xxxxxxxx<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> _www.arup.com_ <file://www.arup.com><o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>><o:p> </o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> ____________________________________________________________<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> Electronic mail messages entering and leaving Arup business<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> systems are scanned for acceptability of content and viruses<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> ======================================================<o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> You received this e-mail because you are subscribed <o:p></o:p></SPAN></FONT></PRE><PRE><FONT face="Courier New" size=2><SPAN style="FONT-SIZE: 10pt">>> to the BLDG-SIM@xxxxxxxx mailing list. 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