[Equest-users] eQUEST vs EnergyPlus: Fan Energy Consumption

[Simge Andolsun]

Dear EnergyPlus users,

We have modeled a test case with exactly same inputs in eQUEST and
EnergyPlus to compare the results of these programs for an identical
situation. This case had a PTAC system with electric heating. The fan
inputs were as follows in both eQUEST and EnergyPlus:

·         0.3 inWG (74.7 Pa), 0.6 total efficiency fraction

·       In eQUEST: Fan control is constant volume, with night time cycling
In EnergyPlus: Fan control is constant volume (fan control schedule=1) when
the fans are scheduled to be on and it is cycling (fan control
schedule=0) when the fans are scheduled to be off. I used
AvailabilityManager:NightCycle to set this control (Please let me know
whether there is any better way to model the same fan control condition in
eQUEST and EnergyPlus).

·         California Title 24 fan availability schedules were used in both
programs. These schedules turn the fan off during the hours listed below:

Weekdays: Between 8pm-5am

Saturday: Between 3pm-5am

Sundays and Holidays: Off all day.

The fan energy consumption of the two programs ended up differing from each
other significantly. Attached are the charts that show the results of the
coldest and warmest days. Would you let me know what might be the reason
for this difference between the two programs?

Thank you very much in advance for your help,
Best Regards,
S. Andolsun, Ph.D.
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