How about changing the system type to VAV and adding the waterside
economizer coil? For instance, if the system type is supposed to be fan
coils, you could set the minimum fan speed to 1.00, minimum air fraction
to 1.00, set your minimal static pressure on the fan- maybe 0.25" or so,
zero out the pressure drop across the "economizer coil", and zero out
additional heat gain from the fan due to the "economizer coil".

Does anyone have experience with this methodology producing reliable
results compared to the methodology suggested in previous posts? Any
feedback is appreciated.

James D. Waechter, P.E., LEED A.P.