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<p><font size=3 color=blue face="Times New Roman"><span style='font-size:12.0pt;
color:blue'>I agree that whole-building energy models are not the way to go for
chilled water simulation. ASHRAE Research Project 141 developed a program
for simulating central chilled water systems. The original work was done by the
</span></font><font color=blue><span style='color:blue'>University</span></font><font
color=blue><span style='color:blue'> of </span></font><font color=blue><span
style='color:blue'>Illinois</span></font><font color=blue><span
style='color:blue'> at Urbana-Champaign. Dr. James A. Corll converted this
mainframe program for use on PCs. He made extensive modifications to the
program to add features and correct some program bugs. His version, WTRSYM, was
a powerful tool for simulating chilled and hot water systems. </span></font></p>
<p><font size=3 color=blue face="Times New Roman"><span style='font-size:12.0pt;
color:blue'>The program allows you to describe a chilled water piping network
including pipe size, length, and fittings. It models variable and constant
speed pumps, chillers, coils and coil loads, pressure relief valves, check
valves, and control valves including two-way, three-way, and wild coils.</span></font></p>
<p><font size=3 color=blue face="Times New Roman"><span style='font-size:12.0pt;
color:blue'>Program output includes an echo of the program input, a summary of
control valve conditions including Cv and flow, a summary of air side and water
side coil conditions, and a list of pressure, flow rate, and temperature at
every node in the system. It also notes the load on each chiller and lists
overloaded coils. </span></font></p>
<p><font size=3 color=blue face="Times New Roman"><span style='font-size:12.0pt;
color:blue'>There are several applications for the program. If the total system
capacity is less than the total of the peak design cooling loads, simulations
may be made to see if system inadequacies occur for different load
combinations. A second design application would model proposed changes or
additions to an existing system.</span></font></p>
<p><font size=3 color=blue face="Times New Roman"><span style='font-size:12.0pt;
color:blue'>The program can also simulate problems which occur under certain
load conditions and may indicate the cause or solution of the problem. It may
be used to simulate corrective measures to a problem. The program will also
allow simulating the effects of turning off part of the equipment under part
load conditions for energy conservation.</span></font></p>
<p><font size=3 color=blue face="Times New Roman"><span style='font-size:12.0pt;
color:blue'>There are a couple of drawbacks to the program. First, Dr. Corll
did not design much of a user interface. The input actually dates back to the
mainframe roots of the program. The input must be in a column oriented format
similar to punch cards in order to work. Second, it is very easy to create a
Chilled Water network that WTRSYM cannot solve. The program uses an iterative
algorithm that must converge to arrive at an answer. The combination of these
two things make WTRSYM a very difficult program to work with. It does, however,
give you results that make it all worth while. </span></font></p>
<p><font size=3 color=blue face="Times New Roman"><span style='font-size:12.0pt;
color:blue'>I have use WTRSYM on several projects over the last 20 years and
have never been disappointed with the results. The program can give
amazing insight into a chilled water system, especially one that has been added
on to for the last 20 or 30 years.</span></font></p>
<p><font size=3 color=blue face="Times New Roman"><span style='font-size:12.0pt;
color:blue'><a href="http://www.elitesoft.com/web/hvacr/elite_hsym_info.html"
target="_blank"></a></span></font><a
href="http://www.elitesoft.com/web/hvacr/elite_hsym_info.html" target="_blank"><img
border=0 width=200 height=42 src="cid:image001.gif@01C99BFE.C211BA70"
align=left
alt="Elite Software Logo. Click here to open window on Elite's HSYM program."></a><font
color=blue><span style='color:blue'><a
href="http://www.elitesoft.com/web/hvacr/elite_hsym_info.html" target="_blank"></a>Unfortunately,
I lost contact with Dr. Corll several years ago. I am not sure if his program
is still available. Elite Software bought the rights to use his program as the
calculation engine for their HSYM program. Elite Software has added a Windows
user interface, which should be very helpful. It will not help with the
convergence problem. HSYM is available through Elite. If you are interested,
click the Elite Software Logo. Understand that this is a qualified
recommendation. I have no direct experience with Elite's version of the program.
</span></font></p>
<p><font size=3 color=blue face="Times New Roman"><span style='font-size:12.0pt;
color:blue'>Mike Roberts</span></font></p>
<p class=MsoNormal><font size=3 color=blue face="Times New Roman"><span
style='font-size:12.0pt;font-family:"Times New Roman";color:blue'> </span></font></p>
<p class=MsoNormal><font size=3 color=blue face="Times New Roman"><span
style='font-size:12.0pt;font-family:"Times New Roman";color:blue'> </span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'>-----Original Message-----<br>
<b><span style='font-weight:bold'>From:</span></b>
bldg-sim-bounces@lists.onebuilding.org
[mailto:bldg-sim-bounces@lists.onebuilding.org] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Bill<br>
<b><span style='font-weight:bold'>Sent:</span></b> 03/03/2009 10:55 AM<br>
<b><span style='font-weight:bold'>To:</span></b> 'Sparks, Jason';
bldg-sim@lists.onebuilding.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Bldg-sim] Chilled
Water Loop / Bldg Modeling</span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Calibri><span
style='font-size:11.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=blue face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:blue'>Jason,</span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt;font-family:"Times New Roman"'> </span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=blue face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:blue'>Based on your
description, I don't think your best option is a whole-building energy model
such as eQuest or EnergyPlus. I believe your best option is an empirical
model. I suggest you review the ASHRAE 1050-RP research, and see if the
models presented there might be more applicable to your task. They will
also be much, much easier to learn and use. You can either use the
1050-RP toolkit, or depending on your needs, you might find it handier to
create spreadsheet models. You can find some good examples of the use of
those approaches in the Texas A&M web library.</span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt;font-family:"Times New Roman"'> </span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=blue face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:blue'>These approaches are
typically described in the context of Measurement and Verification, but they
are applicable to many other energy analyses.</span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt;font-family:"Times New Roman"'> </span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=blue face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:blue'>--Bill</span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt;font-family:"Times New Roman"'> </span></font></p>
<div class=MsoNormal align=center style='margin-left:.5in;text-align:center'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt;font-family:"Times New Roman"'>
<hr size=2 width="100%" align=center>
</span></font></div>
<p class=MsoNormal style='margin-right:0in;margin-bottom:12.0pt;margin-left:
.5in'><b><font size=2 face=Tahoma><span style='font-size:10.0pt;font-family:
Tahoma;font-weight:bold'>From:</span></font></b><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'>
bldg-sim-bounces@lists.onebuilding.org
[mailto:bldg-sim-bounces@lists.onebuilding.org] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Sparks, Jason<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, March 03, 2009 7:46
AM<br>
<b><span style='font-weight:bold'>To:</span></b> bldg-sim@lists.onebuilding.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [Bldg-sim] Chilled Water
Loop / Bldg Modeling</span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Calibri><span
style='font-size:11.0pt'>I’ve been tasked with finding a software package
that can model our chilled water system. We have a district plant
that distributes chilled water to many buildings on our campus. My
specific task is to model the chilled water system of one specific building,
then those results will determine if we continue looking for a different
software package, or proceed to model the other buildings. Pretty much
they want a computer model of the buildings chilled water system that can
predict the chilled water flow requirements for each AHU & the total
building as a function of the buildings chilled water supply temperature,
outside air conditions, and air handling unit flow rates.</span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Calibri><span
style='font-size:11.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Calibri><span
style='font-size:11.0pt'>I’m looking at eQuest & EnergyPlus (as
they’re the only free options I’ve found so far to play with), and
I’d really like some opinions/suggestions on how to proceed.</span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Calibri><span
style='font-size:11.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Calibri><span
style='font-size:11.0pt'>Thanks</span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Calibri><span
style='font-size:11.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Calibri><span
style='font-size:11.0pt'>Jason</span></font></p>
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