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.