The main function of air conditioning system is to keep the air inside the pressurized compartments to the correct pressure and temperature. This system (ATA21); is responsible for monitoring the temperature of cabin pressurization control, avionics compartment ventilation and cooling and heating of the wineries.
The Airbus A320 is equipped with two “packs” or packages that are placed in the belly, near the root of the wing and front landing gear. These packs provide dry for cabin air conditioning, ventilation and pressurization air. The hot air that reaches the pack is delivered by the pneumatic system bleeding engines. Regulating the flow of air entering the pack have the FCV (Flow Control Valve) that doubles as shutoff valve packages.
Once inside the packs, the air is controlled by the ACSC (Air Conditioning System Controllers); calculating flow demand FCV and placed in position, regulating the inflow pack. For the air outlet, the same ACSC control the temperature demanding a minimum and a maximum. This control is accomplished by modulating the entrance gates impact air (Ram Air Inlet Doors) and valve bypass (bypass).
The air leaving the pack, after being regulated and controlled, goes into a mixing unit (mixer unit). This unit, the air mixture packets recirculated cabin air, that is; X% of the air in the cabin is mixed with “new” air. We could say that there is some part of the air we breathe will come out of the cockpit and back again to it. The reason is none other than save fuel since all air from the pneumatic system comes airplane engines and the more demand is requested, no more consumption by the motor.
In an emergency, this mixer unit can receive air directly from outside the aircraft. For example, in case there smoke, the air inlet damper emergency impact would open and clean up contaminated air. It also serves to acclimate the aircraft on the ground as the cold or warm air that we feel when we enter a plane comes from a yellow hose that connects to the stomach, namely the mixing unit.
This system normally operates automatically, adjusting the cabin altitude and rate of climb to make it comfortable. The pressurized in an A320 cabin areas are technical crew, Bay avionics, cabin and cargo compartments.
Although it sounds complicated, it is rather simple. Recall that the plane when it rises, it is inflating like a balloon and when you drop down the air slowly to comply with environmental pressure … deflated. Knowing this, the elements of this system are logical. The air leaves the packages and will pressurized areas, but there has to be something that controls how much air can or should escape the plane, lest they too swell. That something is the outflow valve, and his work is that, regulate the amount of air coming out of the pressurized areas.
This system is automated and is accomplished through two CPCs (Cabin Pressure Controllers). Caca CPC controls an electric motor of the outflow valve and communicates with various aircraft systems to optimize the pressurization / depressurization. Each CPC controls a system and are alternatives. On a flight works 1 2 being ready to go in case there is failure in the 1 and on the next flight will be the 2nd whom you work, taking 1 looking closely. Another third engine installed if the previous two fail, but this is handled manually from cabin.
To protect the body against excessive differential pressure cabin, has installed two safety valves on the rear pressure bulkhead, protecting the aircraft against negative differential pressure also.
This complements the ventilation air conditioning to have an extra air circulating between the avionics that will suppose quite as warm and need a flow of cold air (such as home computers). This air passes through the avionics compartment, the cockpit instruments and panels breakers.
Operating in the avionics bay is as simple as having a fan blowing air and another extracting, creating a current between them. These two fans are always operating while the airplane’s electrical system is powered.
The AEVC (Avionics Equipment Ventilation Computer) controls the fans and the configuration of the inlet and outlet gates fuselage response to the logic ground / flight and the temperature of the “skin” of the fuselage. There are three settings for these doors:
Ventilation of cellars
Although this is an option and not come as standard (the planes are like cars, though hard to believe), we explain above wineries ventilation. It is the simplest of all because the main cabin air either a fan or pressure difference in flight and after having it circulating in the compartment, is cast out of the plane gets.