Graphics Programs Reference
In-Depth Information
Return Air
Air that is being returned from the space back into the
system is called
return air
. It can also be used for relief air or
transfer air, but exhaust can also make a good candidate.
Exhaust Air
Air that is destined to leave the space as well as the
system is called
exhaust air
. There can be different types of exhaust
air that you may want different systems for, such as, for example,
Kitchen Exhaust, Toilet Exhaust, General Exhaust, and Smoke
Exhaust.
Other Air
Other Air seems like a logical candidate for relief air or
outside air; however, systems cannot be made with Other Air. In
addition, if you want to utilize CFM calculations, you shouldn't use
the Other Air system because it doesn't do those calculations.
Fitting
The Fitting system type is merely a pass-through
connection; there is no effect on the airflow or definition of the
system. However, fittings do affect pressure-loss calculations.
Global
Global connections can be either Supply Air, Return Air, or
Exhaust Air. When you are creating the system in the project, you
will be given the opportunity to select the type of system it should
be. Fans are a good example of equipment that may use global
connections because the same type of fan may be used in multiple
system types.
Loss Method
Not Defined, Coefficient, and Specific Loss are the options here, and
Coefficient and Specific Loss each activate another parameter. Specific
Loss should be used where the loss is known from a catalog or cut sheet.
The pressure loss is taken literally as the entered value for Pressure
Drop.
