Central system air is usually supplied to a zone through a terminal unit such as a single duct VAV reheat box. Sometimes, however, it is desirable to supply central system air directly to a zone without any zone level control or tempering, e.g. when used in conjunction with a unitary packaged system.
The Direct Air ADU creates the capability of supplying central system air directly to a zone. The data required for the unit consists of the unit name, availability (on/off) schedule, and a maximum flow rate.
For the units to work correctly, it is important in any systems including Direct Air ADUs for the sum of the maximum zone air flow rates to be equal to the maximum central system flow rate. The central air system flow rate is specified in the air loop AHU data.
This is a read-only label that is automatically generated by the software and which incorporates the name of the zone in which the ADU is located.
The design maximum volume flow rate (in m3/s or ft3/min) specified for the Direct Air ADU. This field may be auto-sized.
This is the schedule that determines whether or not the unit is available for each timestep of the simulation. A schedule value greater than 0 (usually 1 is used) indicates that the unit can be on during the timestep . A value less than or equal to 0 (usually 0 is used) denotes that the unit must be off for the timestep .