How the Temperature is Controlled Into the Cabin in the Aircraft

869 Words2 Pages

HOW TEMPERATURE IS CONTROLLED INTO THE CABIN IN THE AIRCRAFT AIR CONDITIONING SYSTEM (M2):

HOW COLD AIR IS PRODUCED FROM THE AIR CYCLE MACHINE

The normal mode is based on the pack temperature demand, which corresponds to the lowest zone temperature demand coming from the Zone Controller.

The pack controller sets the pack temperature demand to 20°C as default value, that is, if there is no demand signal sent by the zone controller. The limited pack temperature demand is then compared to the actual temperature measured by:
• the pack temperature sensor (8),
• the pack discharge temperature sensor (10).
The Pack Controller is the one responsible to control the three valves to meet the desired cabin demand temperature from the Zone Controller:
1. Ram Air Inlet Door 2. Ram Air Outlet Door 3. Temperature Control Valve
The following sensors are used for the regulation of temperature outlet from this Air Cycle Machine:
Sensors 1-3: measure the actual air flow through Flow Control Valve into the ACM
Sensors 4-6: measure the air temperature across the Compressor
Sensors 6-7: measure the efficiency of the Heat Exchanger with the use of Ram Air cooling

COLD AIR FROM AIR CYCLE MACHINE
HOW THE TEMPERATURE IS REGULATED FROM AIR CYCLE MACHINE GOING INTO THE CABIN
Trim air PRVs 1 and 2 supplies pressure regulated hot air to the various trim air valves for fine temperature adjustment. The two trim air systems can be interconnected through the trim air shut-off valve fitted on the hot air manifold. Each trim air PRV has a hot air
Pressure regulation function and a hot air supply shut-off function.
The ZONE CONTROLLER receives feedback from Cockpit and Cabin Zone temperature demand based on the inputs from the Crew on the temperature selecto...

... middle of paper ...

... selected to the MANUAL position.
In this position, electric power is removed from the controller (and subsequently the climb and dive solenoids associated with the primary outflow valve). All changes to the outflow valves are now commanded using differential pressure from cabin and ambient sources. Placing the MANUAL valve in the UP position will increase cabin altitude, and placing the valve in the DOWN position will decrease cabin altitude.
The amount of cabin altitude change and the cabin altitude rate of change is controlled by the amount of time the MANUAL valve is held in the UP or DOWN position. Because the manual valve uses cabin pressure to open and close the outflow valves, reaction time will increase at low cabin Delta-P. Safety features in the manual toggle valve will not allow rate selections beyond Delta-P limits.

Works Cited

Airbus Training Manual

More about How the Temperature is Controlled Into the Cabin in the Aircraft

Open Document