[Equest-users] Fan demand from Performance Outputs tab exceeds fan power from Air-Side HVAC tab

Edgar Arevalo coldfusion6468 at gmail.com
Thu Aug 30 11:44:01 PDT 2018

I have received this question generated by the LEED v4 Minimum Energy
Performance calculator stating "The fan demand (as reported in the
Performance Outputs tab) for the baseline and/or proposed exceeds the fan
power as reported in the Air-Side HVAC tab (total system fan power) by more
than 5%. Ensure that the values reflected in the Air-Side HVAC sheet are
accurate and appropriately reflect the modeled fans."

I added the baseline fan demand in the Air-Side HVAC tab based on the
values generated from eQuest reflected from what I was required to do
according to Appendix G for System 3 and System 9.  I added the proposed
fan demand in the same tab based on the Mechanical Schedule of the recent
project drawings.  In eQuest, I made sure the fan power for each unit in
the proposed was modeled with the same values taken from the Mechanical
Schedule.  By that logic, the fan power that eQuest generated for the
baseline and proposed models would match the fan demand noted in the
Air-Side HVAC tab.  After running simulations for both models and adding
them to the Performance Outputs tab, the total ventilation fan power for
both models exceeded the fan demand for both baseline and proposed in the
Air-Side HVAC tab.  How can that be?  I made sure the fan power for each
individual system was identical in the Air-Side HVAC tab and eQuest for
both the baseline and proposed models.  Even the ventilation operation
schedules for both models are identical.  And I didn't enter a multiplier
to any of the systems.

Any help would be greatly appreciated.

- Edgar Arevalo
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