IES-VE User Forum

Hello,
I am new to this forum and was wondering if any of the experienced users could comment on the following issue:
I am trying to estimate energy savings with a reduction in the supply air CFM.
I am not auto sizing any fan and modeling the air handlers as built but I see absolutely no savings in the fan energy despite more than 30% reduction in the supply air volume.

I am using a VAV reheat system.

No other parameters of the model are changing but still the reduce CFM doesn't reflect in the fan energy savings.
Any comments on if anybody else ever encountered such problem and its solution?
Thanks

A few things could be going on here... are you seeing a change in fan energy at all (either an increase or decrease)? When you reduce the supply air, are you changing the values in the flow controller or in the fan component? You will need to change both.

The Flow Controller is the piece of the ApHVAC network that determines airflow to the space. If you do not change the flow controller, the flow to the room will not change.

The Fan Component is the meter that determines how much energy is required to provide the flow set in the controller. If you change the flow controller but not the fan component, the energy will be determined using the same fan curve. That is, you'll have the same fan, just turned down to a lower flow.