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<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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