Aircraft Air Conditioning System

Created by

@ImpressedIntellect

Study Notes

Vapour Cycle Air Conditioning System

The receiver-dryer serves as a reservoir for the liquid refrigerant and filters out moisture from the system.
It is located in the high side between the condenser and the expansion valve.

Compressor and Refrigeration Cycle

The system is divided into two sides: the low side (accepts heat) and the high side (disposes of heat).
The compressor increases the pressure and temperature of the refrigerant vapour.
The refrigeration cycle starts at the receiver-dryer and flows through the expansion valve, evaporator, and compressor.

Evaporator and Cooling Process

The evaporator is the unit that produces the cold air, where heat is absorbed by the refrigerant.
Warm air is blown through the thin metal fins that fit over the evaporator coils, and the heat is absorbed by the refrigerant.
When heat is absorbed, the refrigerant changes from a liquid to a gas without increasing its temperature.

Refrigerant and System Requirements

R134a is the exclusively used refrigerant in aircraft applications due to its low environmental impact.
The refrigerant must be highly volatile (high vapour pressure and low boiling temperature).
Only the refrigerant specified in the aircraft manufacturer's maintenance manual should be used for servicing the system.

Importance of Moisture Removal

Moisture must be removed from the system, as a single drop can freeze in the expansion valve and stop the entire air conditioning process.
Water reacts with the refrigerant to form hydrochloric acid, which is highly corrosive to the metal in the system.

Description

This quiz covers the components and functioning of an aircraft air conditioning system, including the receiver-dryer, thermal expansion valve, and evaporator. Learn about the properties of refrigerants and their applications in aircraft.