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<DIV><SPAN class=474480811-10102002><FONT face=Arial color=#0000ff size=2>Has
anyone ever told you guys that you were nuts! By the time you get done
with all of your guessing, manipulation, trickery, and manual curve
creation - you could have just made an intelligent guess and been
closer. With the added bonus of saving a bunch of time. Unless it is
some kind of PhD kind of thing.</FONT></SPAN></DIV>
<DIV><SPAN class=474480811-10102002><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=474480811-10102002><FONT face=Arial color=#0000ff
size=2>Mark</FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B> Steve Gates
[mailto:stvgates@pacbell.net] <BR><B>Sent:</B> Wednesday, October 09, 2002
7:44 PM<BR><B>To:</B> BLDG-SIM@GARD.COM<BR><B>Subject:</B> [BLDG-SIM] Static
Pressure Reset modeling in DOE 2<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>Currently there is no "optimized static pressure
control" for fans/ducts in DOE-2. However, J. Hirsch & Associates
has funding to implement such a mechanism in DOE-2.2 within the next few
months. The funding is provided by Southern California Edison as part of
their "Energy Design Resources" program (<A
href="http://www.energydesignresources.com/">http://www.energydesignresources.com/</A>).
These enhancement will be incorporated into both DOE-2.2 and eQUEST (not
PowerDOE), and will be made available to the user community at no
charge.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>This control mechanism will be similar to the
head reset controls already implemented for variable-flow pumping systems
in DOE-2.2, where the pump head setpoint can be reset based on the hourly head
demand of the worst-case valve. The actual pump head is then a function of the
worst-case valve head, plus the additional variable-flow head losses of
the loop piping and the central plant equipment. This control
sequence maximizes the potential savings of variable-speed pumps, as the
required speed of a pump is dependent on both the flow as well as the head
requirement; with the head requirement usually being the dominant factor.
(The maximum head of a pump varies roughly as the square of the impeller
speed; if the head requirement does not decrease as the flow drops off, then
the speed cannot decrease significantly).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>For fans/ducts, the simple curve-fit that varies
fan power as a function of flow will become obsolete. Instead, DOE-2.2
will keep track of the static requirement of the worst-case VAV box, as
well as ducting, coils, filters, etc. Each component must
be accounted for separately, as the head of all of these devices varies
differently for a given flow. (Some components, such as ducts and
sound traps, experience turbulent flow, and their head varies as the 1.85
power of flow. Other components, such as coils and filters, are more
laminar, and their head typically varies in the range of the 1.1-1.6 power of
flow. Still others, such as a VAV box without an intelligent DDC
system to monitor damper position, will have a constant head requirement; i.e.
a constant head setpoint out toward the end of the ducting.) These
changes will require DOE-2.2 to know about the flow through each component in
the system, the component's head characteristic, as well as the fan map for a
given type of fan (forward-curved, airfoil, etc.) Based on flow and
static requirement, DOE-2.2 will then be able to determine the fan speed and
power consumption. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>In the meantime, you can approximate "optimized
static pressure control" by generating a new curve that causes power to fall
off more rapidly with flow than the default curves. However, this is not
a straightforward task, as you would have to calculate by hand all of the
algorithms we have designed for DOE-2, and repeat the calculations for a
series of flows. Perhaps someone has already done this exercise, and can
share their curves with you.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Steve Gates</FONT></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=babetsk@jbb.com href="mailto:babetsk@jbb.com">babetsk@jbb.com</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=BLDG-SIM@GARD.COM
href="mailto:BLDG-SIM@GARD.COM">BLDG-SIM@GARD.COM</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, October 09, 2002 2:41
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [BLDG-SIM] Static Pressure
Reset modeling in DOE 2</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>
<DIV>To Doe 2 Users:</DIV>
<DIV> </DIV>
<DIV>Hello,</DIV>
<DIV> </DIV>
<DIV>Does anybody know if there is a way to model (in DOE-2) an
"optimized static pressure control", that is a control method where the
controller dynamically adjusts the static pressure set point based on the
position of the modulating devices in the VAV terminal units? </DIV>
<DIV> </DIV>
<DIV>Thank you</DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial size=2>Konstantin E. Babets, Ph.D.</FONT></DIV>
<DIV><FONT face=Arial size=2>CFD/Energy Modeling Engineer</FONT></DIV>
<DIV><FONT face=Arial size=2>Jaros Baum and Bolles<BR>Consulting
Engineers<BR>80 Pine Street<BR>New York NY 1005<BR>Tel:
212.530.9455<BR>Fax: 212.269.5894<BR></FONT></DIV>
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