Evaporator - Subaru LEGACY 2002 Quick Reference Index

HVAC System (Heater, Ventilator and A/C)

14.Evaporator

A: MECHANISM
Air pushed by the blower passes through the cooling fins and tubes of the evaporator. Since the
air is warmer than the refrigerant, the heat of air moves to the refrigerant through the fins and
tubes. As the low-pressure refrigerant moves through the evaporator, heat from the air causes the
refrigerant to boil. By the time the refrigerant has passed through the evaporator, it becomes vapor.
Moisture in the air condenses to water drops as it moves around the tubes and fins of the evapo-
rator. Water and dirt are then discharged outside the vehicle through a drain hose.
The evaporator is a laminated type and consists of thin, rectangular aluminum plates arranged in
multiple layers and fins that are attached between them. During flow through the evaporator, the
state of the refrigerant changes as follows:
Misty refrigerant (very close to liquid form) from the expansion valve at a low-pressure, enters the
lower tube of the evaporator, where it soaks up heat from the compartment. The refrigerant boils
and vaporizes quickly due to the rapid heat exchange. Then the refrigerant is pushed upward by
the force of the bubble generated during the heat exchange and enter the upper tube. When it
reaches the upper tank, the refrigerant is in a thoroughly vaporized state.
The evaporator has a single tank, and its surface has been given the following treatments.
! Rustproof treatment
! Waterproof treatment
! Moldproof treatment
(1) From receiver drier
(2) To compressor
(3) Misty refrigerant
(4) Vapor
(5) Expansion valve
EVAPORATOR
AC-34
B4H1511A