The VAV option allows you to model Variable Air Volume (VAV) HVAC configuration with optional preheat, air handling unit heating and cooling coils and reheat and several different heating coil options. You can select series or parallel fan powered terminal units (also known as powered induction units or PIU). There are options to control the air distribution system in various ways including the ability to ensure minimum fresh air delivery to each zone, set VAV box minimum flow fraction and various outside air options including an economiser to provide free cooling when appropriate and heat recovery. You can also model heating and cooling coil temperature reset.


Only one VAV system can be defined per building and it can serve up to 400 zones.


Note: the Compact HVAC type must be set to VAV at building level and in all zones which are part of the VAV system. Other zones can have HVAC type Unitary single zone or Fan coil units but not Unitary multizone or CAV.



See also Zone Terminal Units for more on VAV systems.