Higher Total Fresh Air Supply than Expected

asked 2021-09-23 04:35:09 -0600

Debayan93's avatar


I have set up a detailed HVAC System (DX dehumidification, Boiler Heating) for temperature and humidity control for an unoccupied space using DesignBuilder v6. The Building is a single unoccupied zone so has almost no ventilation requirement (0.05 ac/h).

I haven't switched any Mechanical/Natural ventilation from the HVAC tab. Currently, I have set only the infiltration rate (0.1 ac/h) from Construction. However, for this setting, I am receiving a Total fresh air supply (Mech+Nat vent.+Infiltration) between 1 to 3 ac/h. I am not sure from where this extra air supply is supplied into the zone.

Total Fresh Air Supply.

My settings are as followed:

image description

Let me know if someone knows how to resolve this.



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@Debayan93 do you have any window openings or similar settings that would be counted as natural ventilation?

Aaron Boranian's avatar Aaron Boranian  ( 2021-09-23 08:42:05 -0600 )edit

Hi Baron,

the zone currently has no windows or other kinds of openings. I am not sure if I can add the model here in comment or question as a file.

Debayan93's avatar Debayan93  ( 2021-09-23 09:06:04 -0600 )edit