MIDTER

• Is used on most turbine powered aircraft. It makes use of engine bleed air or APU pneumatic air during the conditioning process.

  Air cycle air conditioning
• are often used on reciprocating aircraft. This type system is similar to that found in homes and automobiles

  Vapor cycle air conditioning systems
• Air cycle air conditioning prepares ____ to pressurize the aircraft cabin.


  engine bleed air
• The air cycle system is often called the

  air conditioning package or pack
• The air cycle air conditioning system is supplied with air by the

  aircraft pneumatic system.
• It regulates bleed air from the pneumatic manifold into the air cycle air conditioning system. It is controlled with a switch from the air conditioning panel in the flight deck.

  Pack Valve
• A means for bypassing some of the pneumatic air supplied to the air cycle air conditioning system around the system is present on all aircraft.

  Bleed Air Bypass
• Generally, the warm air dedicated to pass through the air cycle system first passes through a primary heat exchanger.

  Primary Heat Exchanger
• The heart of the air cycle air conditioning system is the

  refrigeration turbine unit, also known as the air cycle machine (ACM).
• s used to remove the water from the saturated air before it is sent to the aircraft cabin

  water separator
• designed to keep the air flowing through the water separator above freezing temperature.

  refrigeration bypass valve
• refrigeration bypass valve is also identified by other names such as a

  temperature control valve, 35° valve, anti-ice valve,
• g is used on most non-turbine aircraft that are equipped with air conditioning.

  Vapor cycle air conditioning
• In vapor cycle air conditioning, heat is carried from the cabin to the outside air by a refrigerant which changes from a liquid to a vapor and back again
• There are two sides to the vapor cycle air conditioning system.

  One accepts heat and is known as the low side. The other gives up heat and is known as the high side.
• are the two components that separate the low side from the high side of the cycle

  The compressor and the expansion valve
• Refrigerant on the low side is characterized as

  having low pressure and temperature.
• Refrigerant on the high side has

  high pressure and temperature.
• was the standard refrigerant used in aircraft vapor cycle air conditioning systems

  dichlorodifluoromethane (R12)
• In most cases, it has been replaced by ____, which is safer for the environment.

  tetrafluoroethane (R134a)
• • R134a is a

  a halogen compound (CF3CFH2)
• it has a boiling point of approximately

  –15 °F
• Refrigerants are sometimes called

  Freon
• acts as the reservoir of the vapor cycle system.


  receiver dryer
• has an adjustable orifice through which the correct amount of refrigerant is metered to obtain optimal cooling

  thermostatic expansion valve
• If the Sensing Bulb sense an increase in temperature, the orifice ____

  slowly open.
• If the Sensing Bulb sense a decline in temperature, the orifice ____

  slowly closes
• Normal Load


  Low heat is Absorb
• Heavy Load


  High heat is Absorb
• are constructed of copper or aluminum tubing coiled into a compact unit

  evaporators
• are attached to increase surface area, facilitating rapid heat transfer between the cabin air blown over the outside of the evaporator with a fan and the refrigerant inside

  fins
• located at the evaporator inlet, changes the high pressure, high temperature refrigerant into low pressure, low temperature refrigerant which continues on into the evaporator


  expansion valve
• is the heart of the vapor cycle air conditioning system.

  compressor
• Modern compressors are either


  engine driven or driven by an electric motor.
• the vapor cycle air conditioning compressor is driven, it is usually a

  piston type pump
• is the final component in the vapor cycle.

  condenser
• It is a radiator-like heat exchanger situated so that outside air flows over it and absorbs heat from the high-pressure, high-temperature refrigerant received from the compressor

  codenser
• is used to heat the aircraft. Electricity flowing through a heating element makes the element warm. A fan to blow air over the elements and into the cabin is used to transfer the heat.

  Electric Heating System
• Most single-engine light aircraft use ______systems to heat the cabin. Ambient air is directed into a metal shroud, or jacket, that encases part of the engine’s exhaust system

  exhaust shroud heating
• is used on many small to medium sized aircraft. It is a heat source independent from the aircraft’s engine(s), although it does use fuel from the aircraft’s main fuel system


  combustion heate