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<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2>Two approaches to consider.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2>1. </FONT></SPAN><SPAN class=578132018-24012008><FONT
face=Arial color=#0000ff size=2>Ask yourself is whether the evaporative cooler
is even capable of providing the level of cooling you tell it (ie:
satisfying your cooling setpoint)? Typically direct evaporative coolers
are not intended to provide full cooling capability just cooling relief.
Address the problem by raising your cooling setpoint in the spaces being served
by the evap coolers. Make sure to use the same cooling schedule for your
baseline model.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2>2. Simulate the HVAC systems in the proposed design
with mechanical cooling that has the same performance as the baseline
but use the direct evap cooler add-on feature as the first stage of
cooling. While your proposed design technically doesn't have
mechanical cooling I believe the intent of Appendix G would require you to
simulate it in order to satisfy your unmet cooling hours. The add-on evap
cooling feature in eQuest is able to deal with the changes in ventilation
air required for direct evap cooling so you can get rid of the crazy
MIN-OA-SCH. The user manuals should give you all the info you need
about the evap cooling keywords you will want to use. I think there is
even a diagram showing how the evap cooling add-on ties into the HVAC
system.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2> </FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2>As far as your comment about fixing one problem to create
another....welcome to energy modeling in DOE2.2. </FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2> </FONT></SPAN><SPAN class=578132018-24012008><FONT
face=Arial color=#0000ff size=2></FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2>good luck</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2>Mike</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008>
<DIV align=left><FONT face="Arial Black" size=2>Michael Tillou, PE,
LEED</FONT></DIV>
<DIV align=left><FONT face="Arial Black" size=2>Tillou Engineering,
LLC</FONT></DIV>
<DIV align=left><FONT face="Arial Black" size=1>Williamstown, MA
01267</FONT></DIV>
<DIV align=left><FONT face="Arial Black" size=1>P:
413-458-9870</FONT> <FONT face="Arial Black" size=1>C:
413-652-1087</FONT></DIV></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=578132018-24012008> </SPAN></DIV>
<DIV dir=ltr align=left>
<HR tabIndex=-1>
</DIV>
<DIV dir=ltr align=left><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>Kearns,
Patrick<BR><B>Sent:</B> Monday, January 21, 2008 5:17 PM<BR><B>To:</B>
bldg-sim@lists.onebuilding.org<BR><B>Subject:</B> [Bldg-sim] Direct Evaporative
Coolers & the eQUEST Games<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV><SPAN class=817325921-21012008>
<DIV><FONT face=Arial><SPAN class=817325921-21012008>Help! </SPAN>I have
been modeling a car dealership which uses several <SPAN
class=817325921-21012008>disparate </SPAN>systems in combination to condition
spaces.</FONT></SPAN></DIV></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>The baseline HVAC
system is Packaged Single Zone with Gas Heat.</FONT></SPAN></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>The actual design for many
of the service bays is:</FONT></SPAN></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>Direct Evaporative
Cooler</FONT></SPAN></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>Unit
Heater(s)</FONT></SPAN></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>Exhaust
Fans</FONT></SPAN></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>For purposes of modeling
the actual design, it seemed appropriate to model the system as "Evaporative
Cool' with "Furnace" selected for heat. The OA fraction was set to 1.0
(more on this later). Actual design capacities were input into the
model. The unfortunate by-product of this (as is often the case) was that
there were a bunch of unmet hours (76), mostly cooling.</FONT></SPAN></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>So after playing around
with several settings, the only way to get the unmet cooling hours down seemed
to be to change the system type back to "Package Single Zone" and set the
unitary power to 0 for the 'compressor' which really does not exist. This
makes the unmet hours go away, but seems to create a higher heating load,
despite the fact that the actual design has higher thermal efficiency than the
baseline. The space heating almost doubles from the baseline to the
proposed.</FONT></SPAN></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>My suspicion has been that
eQUEST does not realize that the evap. coolers only run during the summer, and
thinks it has to heat 100% OA year-round. Appendix G says that the minimum
outdoor ventilation rates should be the same (right or wrong) for the proposed
and baseline designs. So...my solution was to set a minimum OA schedule,
with the summer being 1 and the winter at 0. </FONT></SPAN><SPAN
class=817325921-21012008><FONT face=Arial>Well...this may be closer to reality,
but now the unmet hours spike to 423!</FONT></SPAN></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>So...it seems to be the
recurring problem of fixing one problem, only to create another one. Any
ideas on how better to simulate this?</FONT></SPAN></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>Thanks for any tips in
advance.</FONT></SPAN></DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=817325921-21012008><FONT face=Arial>Regard,</FONT></SPAN></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV align=left><FONT face=Arial>Patrick A. Kearns, P.E.</FONT></DIV>
<DIV align=left><FONT face=Arial>Nexant, Inc.</FONT></DIV>
<DIV align=left><A href="http://www.nexant.com/"><FONT
face=Arial>www.nexant.com</FONT></A></DIV>
<DIV align=left><FONT face=Arial>303-998-2479 Office</FONT></DIV>
<DIV align=left><FONT face=Arial>303-918-8731 Mobile</FONT></DIV>
<DIV align=left><A href="mailto:pkearns@nexant.com"><FONT
face=Arial>pkearns@nexant.com</FONT></A></DIV>
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