Environmental Systems Flashcards
How is the heat removed from an aircraft cabin with a vapor cycle air conditions system?
Absorbed by then refrigerant in the evaporator then carried outside the aircraft to the ambient air in the compressor
What produces the cool air in a vapor cycle air conditioning system?
Warm cabin air is blown across the refrigerant. The air leaves the evaporator cool.
What is used as the refrigerant in a vapor cycle air conditioning system?
A freon type liquid known as refrigerant 12 or R-134a
What is the state of refrigerant as it leaves the compressor?
High pressure gas.
What is the state of refrigerant as it leaves the condenser?
High pressure liquid
What is the state of the refrigerant as it leaves the expansion valve?
Low pressure liquid
What is the state of the refrigerant as it leaves the evaporator?
Low pressure vapor
How is the compressor lubricated?
Refrigerant oil is mixed with refrigerant and it circulates through the compressor and entire system.
What is the function of the thermostatic expansion valve?
Meters just enough liquid refrigerant into the evaporator that all of it will be evaporated by a time it leaves the evaporator coils.
How is refrigerant put into the system?
Through service valves on the low side of the system using a manifold gauge.
How should the components in the low side of a properly operating vapor cycle cooling system feel?
they should feel cool.
How is a vapor cycle cooling system checked for refrigerant leaks?
Hold the probe of an electronic leak detector below any suspected fitting or component. If theres a leak the detector will make a sound.
What safety equipment should be worn when charging a vapor cycle cooling system?
A safety face shield that protects the entire face.
What are two types of air conditions systems that may be installed on an aircraft?
Air-Cycle system and Vapor-Cycle system
