Figure 7-4.Diagram of an electrostatic filter.
The point where water vapor condenses is called
the dew point. True /False
Q6. What condition exists when the dry-bulb,
wet-bulb, and dew-point temperatures are the
What are the two types of filter designs?
What is the primary factor that determines the
temperature and humidity required for room
Learning Objective: Recognize basic types of
air-conditioning systems, and understand the operation,
maintenance, and repair methods and procedures.
A complete air-conditioning system includes a
means of refrigeration, one or more heat transfer units,
air filters, a means of air distribution, an arrangement
for piping the refrigerant and heating medium, and
controls to regulate the proper capacity of these
components. In addition, the application and design
requirements that an air-conditioning system must
meet make it necessary to arrange some of these
components to condition the air in a certain sequence.
For example, an installation that requires re-heating of
the conditioned air must be arranged with the
re-heating coil on the downstream side of the
dehumidifying coil; otherwise, re-heating of the
cooled and dehumidified air is impossible.
There has been a tendency by many designers to
classify an air-conditioning system by referring to one
of its components. For example, the air-conditioning
system in a building may include a dual duct
arrangement to distribute the conditioned air;
therefore, it is then referred to as a dual duct system.
This classification makes no reference to the type of
refrigeration, the piping arrangement, or the type of
For the purpose of classification, the following
definitions are used:
An air-conditioning unit is understood to consist
of a heat transfer surface for heating and cooling,
a fan for air circulation, and a means of cleaning
the air, motor, drive, and casing.
A self-contained air-conditioning unit is
understood to be an air-conditioning unit that is
complete with compressor, condenser,
evaporator, controls, and casing.