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<p class=MsoNormal>Hello Bldg-Sim and eQuest Users,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I am having difficulty in eQuest V3.61 build 5653 (equivalent
to 3.61e) setting up an energy recovery wheel for an AHU with 60% min OA by
design serving typical offices/classrooms. Without energy recovery, the
chiller run-hours seem reasonable (about 4,000 hrs) and I am getting very
little coincident cooling/heating in the winter months based on the SS-C report
for the AHU. The AHU is set up with an enthalpy economizer and a min OA
schedule that is set to 0.001 for all hours to allow for economizer control
during night-cycle. The AHU runs for 6,907 annual hours including 3,749 night
cycle hours. The zone thermostat type is proportional with a 2°F throttling
range. All cooling and heating load hours are met and the chiller does not
operate at outside air temperatures lower than 48°F.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Once I enable the airside energy recovery (enthalpy wheel), the
chiller run-hours jump to nearly 7,400 hours and there are a significant amount
of coincident cooling/heating hours in all winter months. The chilled water
loop control is set to demand (although I’ve tried a snap schedule
resulting in many unmet cooling hours). I am controlling the ERV with the
mixed air temperature and an exhaust bypass. I’ve tried scheduling the
ERV to operate at min OA and with a schedule matching the supply fan hours
minus any optimum start (-999) hours resulting in little change in the results.
I’ve also tried the fixed setpoint control method (using MEP data for the
make-up air temperatures) with no success.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I can reduce the chiller run-time to about 4,600 hours with
the ERV enabled if I disable the night-cycle fan control option. However, the
unmet heating and cooling hours become significant. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>From what I can conclude through my trial and error approach
is that enabling night-cycle control also enables the ERV even with an On/Off
schedule calling for no ERV. When the ERV is enabled, the chilled water loop
also becomes available to satisfy any cooling load that the ERV is creating and
operates down to the coldest hour. I’m not sure if setting the Min OA
schedule of 0.001 (enable economizer) for all hours is affecting whether or not
the ERV is activated.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Any help with this control option or insight to the ERV
calculations are greatly appreciated.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>John T. Forester, LEED AP<br>
Demand Management Institute<br>
35 Walnut Street<br>
Wellesley, MA 02481<br>
Phone: 781 431 1100 x14<br>
Fax: 781 431 1109<br>
email: <a href="mailto:jforester@dmiinc.comweb"><span style='color:blue'>jforester@dmiinc.com</span></a><br>
web: <a href="http://www.dmiinc.com/"><span style='color:blue'>www.dmiinc.com</span></a><o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
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