Mazda Training manual — part 266

Air Conditioning Fundamentals

TC070-05-01S

5 – AIR CONDITIONING
COMPONENTS

38

Figure 21 shows how an accumulator operates. The accumulator tank
separates liquid refrigerant from gaseous refrigerant. Desiccant in the
accumulator tank removes moisture from the refrigerant before it is sent
on to the compressor.

FIGURE 21. The
accumulator tank
prevents liquid
refrigerant from
entering the
compressor, where it
could damage the
A/C system.

From evaporator

ACCUMULATOR TANK

To A/C compressor

Gaseous Refrigerant With Liquid

Liquid Refrigerant

Gaseous Refrigerant

Air Conditioning Fundamentals

TC070-05-01S

5 – AIR CONDITIONING
COMPONENTS

39

REVIEW EXERCISE 5

Match each component on the left to one of the descriptions on the right. Check your
answers with the answer key on page 42.

1. Receiver/Dryer

_____

A. Transfers heat from passenger compartment

to refrigerant

2. Compressor

_____

B. Lowers pressure by restricting refrigerant flow

through a fixed opening

3. Expansion valve

_____

C Transfers heat from refrigerant to outside air

4. Evaporator

_____

D. Removes moisture from refrigerant

5. Orifice tube

_____

E. Lowers pressure by restricting refrigerant flow

through a pintle valve

6. Condenser

_____

F. Raises pressure of refrigerant

Air Conditioning Fundamentals

TC070-05-01S

6 – REFRIGERATION
CYCLE

40

OBJECTIVES


After completing this section, you will be able to:

•

Describe the changes that take place in refrigerant as it flows through the A/C system.

•

Explain the role that each major A/C component plays in the refrigeration cycle.

STAGES OF THE REFRIGERATION CYCLE



Overview

The previous section of this Guide showed that an automotive A/C system is a set of
components that circulate refrigerant through a closed circuit. Refrigerants are special
chemicals designed to absorb and release heat quickly. They have a very low boiling point
— well below 0° F (-18° C) at sea level — and they respond predictably to changes in
pressure. (The next section of this Guide describes refrigerants in more detail.)

Air Conditioning Fundamentals

TC070-05-01S

6 – REFRIGERATION
CYCLE

41

FIGURE 22 The

refrigeration cycle

includes a

high-pressure side

(top) and a

low-pressure side

(bottom). In addition,

the refrigerant

changes from a

vapor (left) to a

liquid (right).

Compressor

Condenser

Receiver/ dryer

Expansion valve

Evaporator

Answers to Review
Exercise 5

1. D

2. F

3. E

4. A

5. B

6. C

Figure 22 shows how refrigerant circulates through an A/C system. As it
flows through a complete cycle, the refrigerant undergoes two changes
in pressure and two changes of state. The four sections of the
illustration show the changes.

The horizontal line divides the cycle into a “high-pressure side” on top
and a “low-pressure side” on the bottom. The high-pressure side starts
at the compressor outlet, extends through the condenser and
receiver/dryer, and ends at the expansion valve.

When refrigerant leaves the expansion valve, its pressure drops and it
enters the low-pressure side. The low-pressure side extends through
the evaporator and into the compressor’s inlet.

The vertical line in the illustration marks the points where the refrigerant
changes state. On the left side of the circuit, the refrigerant is a vapor;
on the right side, it is a liquid.

HEAT

HEAT