Mazda Training manual — part 258

Air Conditioning Fundamentals

TC070-05-01S

2 – WHAT IS AIRCONDITIONING?

6

OBJECTIVES

After completing this section, you will be able to:

•

Describe the purpose of automotive air conditioning.

•

Describe how various A/C system components contribute to passenger comfort.

Although once considered a luxury, air conditioning has become one of the most popular
automotive features. Air conditioning can relieve drivers’ stress and fatigue by providing a
comfortable driving environment. Today, about 80 percent of the vehicles sold in this
country have air conditioners.



BASIC PRINCIPLE

Air conditioning (A/C) creates a comfortable environment by changing the temperature,
humidity, and airflow within the vehicle. The A/C system changes the temperature by
absorbing heat from the passenger compartment and discharging the heat outside the
vehicle.

The refrigerant used in the A/C system absorbs and releases large amounts of heat as it
changes from a liquid to a gas. As the refrigerant circulates through the tubes and hoses of
an operating A/C system, it constantly changes from a liquid to a gas and back to a liquid
again.

The continuous changing of the refrigerant from a liquid to a gas is known as change of
state. This change of state is what allows the refrigerant to remove the heat from the air and
lower the temperature inside the vehicle.

Air Conditioning Fundamentals

TC070-05-01S

2 – WHAT IS AIRCONDITIONING?

7

COMPONENTS ENHANCING COMFORT

To create a comfortable environment for the driver and passengers, an automotive climate
control system uses several components.



Heater

The heater unit uses heated coolant from the engine’s cooling system to warm the air
entering the passenger compartment. A defroster setting redirects heat to the windshield to
remove ice and condensation. Depending on the temperature setting, the heating system
may supply a mix of heated and unheated air to the passenger compartment.



Air Conditioning

Air conditioning enhances the comfort of the driver and passengers by cooling and
dehumidifying the air in the passenger compartment.



Fan

A variable-speed blower fan draws air into the system, where it is cooled or heated
according to system settings. The fan also distributes conditioned air through a series of
vents in the passenger compartment. The variable speed settings allow the occupants to
tailor the airflow to their personal preferences.



Vent Louvers

A/C and heating vents in the passenger compartment usually include louvers that allow
passengers to redirect the airflow up or down, and from side to side. In some cases,
passengers can even shut the vent off completely.

Air Conditioning Fundamentals

TC070-05-01S

2 – WHAT IS AIRCONDITIONING?

8

BASIC AIR CONDITIONING COMPONENTS

Figure 1 shows the basic components of an air conditioning system.

FIGURE 1. An A/C
system includes
five basic
components.

Compressor –
Compresses
the refrigerant
and moves it
through the
system;
increases the
refrigerant
temperature
and pressure.

Condenser –
Transfers heat
from the
refrigerant to
the outside air.

Receiver/ Dryer
or Accumulator
– Removes
moisture from
refrigerant.

Expansion
Valve or Orifice
Tube –
Regulates
refrigerant flow
through the
evaporator.

Evaporator –
Absorbs heat
from the inside
air and
transfers it to
the refrigerant.

HEAT

HEAT

Air Conditioning Fundamentals

TC070-05-01S

2 – WHAT IS AIRCONDITIONING?

9

REVIEW EXERCISE 1

Fill in the words that complete these sentences correctly. Check your answers with the
answer on page 12.

1. The three factors that create the comfortable environment, in a vehicle interior are

___________________, ___________________, and ___________________.

2. Refrigerant absorbs and releases large amounts of ___________________ from inside

the vehicle.

3. When refrigerant changes from a liquid to a gas, it is know as a

________________________.

4. Vents in the passenger compartment usually have ___________________ that allow

passengers to direct airflow up or down, and from side to side.

5. Air Conditioning enhances the comfort of the driver and passengers by

___________________ and ___________________ the air in the passenger
compartment.