I am speculating here, but I think the fan electricity for ideal air loads doesn’t exist since the system doesn’t actually model any equipment. It’s just calculating the heat and mass transfers associated with various zone setpoints, and limit supply air temperatures.
As I understand it, the ventilation rate specified by the
DesignSpecification:OutdoorAir is used to calculate the sensible/latent impact on zone conditions, which is probably done with something like this equation:
Qz = vm * Cp * (Tz - Toa)
Qz = Zone sensible load
vm = ventilation mass flow rate
Cp = Specific heat capacity
(Tz - Toa) = Temperature difference between zone and outdoor air.
So if the additional sensible heat from ventilation is greater or less then the load required to hit zone cooling or heating setpoint, respectively, the system calculates the increase in supply air flow rates required to hit the setpoints given supply air limit temperatures, again by solving the mass heat balance. The ideal air loads system then models the air mixing between supply and outdoor air, and so on, as documented in the Engineering Reference here.
So I don’t think the electricity used to drive the ventilation rate is used, or known at any point. Similar to how the system calculates heating and cooling energy based on similar mass and flow balances, and not by modeling a terminal with coils and fans.
That being said, I could be wrong. You can confirm this by checking the RDD outputs from the OpenStudio component to see if there’s any metric identifying fan ventilation energy, and plugging that in as a requested EnergyPlus output metric to see if it’s providing any values.