Hello Users,

I have a packaged (Heating: Gas-Fired, Cooling: DX) air handling unit with
VAV boxes in the zones. The cooling coil control for the AHU is Zone reset.
I have noticed an odd behavior in the cooling side when I model an exhaust
air heat recovery as follow:

The cooling energy increase from 67.7MBTU to 132MBTU when I include 70%
exhaust air heat recovery which doesn't physically make sense to me.

When I change the cooling coil control to Outdoor air reset the results
change as follow:

The above scenario makes sense in a way that both the heating and cooling
energy decreased by incorporating exhaust air heat recovery.

I appreciate any explanation on the strange behavior of scenario I

Best Regards,

Ahmed Azhari, B.Eng., LEEDR AP