DOC AIRBUS | AMM A320FTEMPERATURE CONTROL - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
Temperature Control - General Diagram ** ON A/C NOT FOR ALL
Temperature Control - General Diagram ** ON A/C NOT FOR ALL
Temperature Control - General Diagram ** ON A/C NOT FOR ALL
The Environmental Control System (ECS) maintains and controls the zone temperatures and the ventilation rate for the two passenger zones and the flight deck.
For this, two air conditioning packs are installed in the unpressurized area in the belly fairing. The packs are supplied with preconditioned air from the main engines, from the APU or from a ground source.
The main part of the cooling system is a 3-wheel air-cycle machine which works as a boot-strap system for heating and cooling. A high pressure water seperation is installed to take full advantage of available bleed pressures and recirculation capability.
The system control is done by eletronic controllers, electro-pneumatic valves and electrically driven valves.
For sufficient ventilation and passenger comfort a common cold air manifold mixes the pack fresh air with recirculated air.
The Environmental Control System (ECS) maintains and controls the zone temperatures and the ventilation rate for the two passenger zones and the flight deck. It also supplies conditioned air to the cargo compartment.
For this, two air conditioning packs are installed in the unpressurized area in the belly fairing. The packs are supplied with preconditioned air from the main engines, from the APU or from a ground source.
The main part of the cooling system is a 3-wheel air-cycle machine which works as a boot-strap system for heating and cooling. A high pressure water seperation is installed to take full advantage of available bleed pressures and recirculation capability.
The system control is done by eletronic controllers, electro-pneumatic valves and electrically driven valves.
For sufficient ventilation and passenger comfort a common cold air manifold mixes the pack fresh air with recirculated air.
The temperature control of the fwd cargo compartment is similar to that of the cockpit and cabin temperature-control system in the heating mode (Ref. 21-43-00).
The Environmental Control System (ECS) maintains and controls the zone temperatures and the ventilation rate for the two passenger zones and the flight deck. It also supplies conditioned air to the cargo compartment.
For this, two air conditioning packs are installed in the unpressurized area in the belly fairing. The packs are supplied with preconditioned air from the main engines, from the APU or from a ground source.
The main part of the cooling system is a 3-wheel air-cycle machine which works as a boot-strap system for heating and cooling. A high pressure water seperation is installed to take full advantage of available bleed pressures and recirculation capability.
The system control is done by eletronic controllers, electro-pneumatic valves and electrically driven valves.
For sufficient ventilation and passenger comfort a common cold air manifold mixes the pack fresh air with recirculated air.
The temperature control of the aft cargo compartments is similar to that of the cockpit and cabin temperature-control system in the heating mode (Ref. 21-43-00).
** ON A/C NOT FOR ALL Temperature Control - General Diagram ** ON A/C NOT FOR ALL Temperature Control - General Diagram ** ON A/C NOT FOR ALL Temperature Control - General Diagram ** ON A/C NOT FOR ALL For this, two air conditioning packs are installed in the unpressurized area in the belly fairing. The packs are supplied with preconditioned air from the main engines, from the APU or from a ground source.
The main part of the cooling system is a 3-wheel air-cycle machine which works as a boot-strap system for heating and cooling. A high pressure water seperation is installed to take full advantage of available bleed pressures and recirculation capability.
The system control is done by eletronic controllers, electro-pneumatic valves and electrically driven valves.
For sufficient ventilation and passenger comfort a common cold air manifold mixes the pack fresh air with recirculated air.
The Environmental Control System (ECS) maintains and controls the zone temperatures and the ventilation rate for the two passenger zones and the flight deck. It also supplies conditioned air to the cargo compartment.
For this, two air conditioning packs are installed in the unpressurized area in the belly fairing. The packs are supplied with preconditioned air from the main engines, from the APU or from a ground source.
The main part of the cooling system is a 3-wheel air-cycle machine which works as a boot-strap system for heating and cooling. A high pressure water seperation is installed to take full advantage of available bleed pressures and recirculation capability.
The system control is done by eletronic controllers, electro-pneumatic valves and electrically driven valves.
For sufficient ventilation and passenger comfort a common cold air manifold mixes the pack fresh air with recirculated air.
The temperature control of the fwd cargo compartment is similar to that of the cockpit and cabin temperature-control system in the heating mode (Ref. 21-43-00).
The Environmental Control System (ECS) maintains and controls the zone temperatures and the ventilation rate for the two passenger zones and the flight deck. It also supplies conditioned air to the cargo compartment.
For this, two air conditioning packs are installed in the unpressurized area in the belly fairing. The packs are supplied with preconditioned air from the main engines, from the APU or from a ground source.
The main part of the cooling system is a 3-wheel air-cycle machine which works as a boot-strap system for heating and cooling. A high pressure water seperation is installed to take full advantage of available bleed pressures and recirculation capability.
The system control is done by eletronic controllers, electro-pneumatic valves and electrically driven valves.
For sufficient ventilation and passenger comfort a common cold air manifold mixes the pack fresh air with recirculated air.
The temperature control of the aft cargo compartments is similar to that of the cockpit and cabin temperature-control system in the heating mode (Ref. 21-43-00).
2. System Description
Pack Temperature Control-System ** ON A/C NOT FOR ALL
Pack Temperature Control-System ** ON A/C NOT FOR ALL
Pack Temperature Control-System ** ON A/C NOT FOR ALL Pack Temperature Control-System ** ON A/C NOT FOR ALL A. System Description of the ECS
The ECS consists of a temperature trim system which has a zone controller and all the necessary valves, sensors and switches to control the air properties in the independent zones. Each of the two air conditioning packs are controlled by its own independent pack controller.
All three controllers, the zone controller and the two pack controllers are in fully digital technics and incorporate, in addition to its control function, a Built In Test Equipment (BITE).
To further enhance reliability all controllers are equipped with one main and one independent secondary computer. In case of a main computer failure the secondary computer takes over the control automatically and provides the necessary control functions. In normal operation the secondary computer's function is limited to display and monitor system functions.
System information, failures and warnings are output from the controllers to be used for display on ECAM and CFDS.
The environmental temperature control is performed via a temperature trim system which consists of all necessary valves, sensors and switches to control the air properties in the independent zones. It is controlled by both Air Conditioning System Controllers (ACSC). Each of the two air conditioning packs are controlled by its own independent ACSC.
Both ACSC's are in fully digital technics and incorporate, in addition to its control function, a Built In Test Equipment (BITE).
To further enhance reliability and get a high level of redundancy, both ACSC's are equipped with two identical lanes. In case of one lane failure the second lane takes over the entire control automatically and provides all functions.
System information, failures and warnings are outputs from the controllers to be used for display on ECAM and CFDS.
The ECS consists of a temperature trim system which has a zone controller and all the necessary valves, sensors and switches to control the air properties in the independent zones. Each of the two air conditioning packs are controlled by its own independent pack controller.
All three controllers, the zone controller and the two pack controllers are in fully digital technics and incorporate, in addition to its control function, a Built In Test Equipment (BITE).
To further enhance reliability all controllers are equipped with one main and one independent secondary computer. In case of a main computer failure the secondary computer takes over the control automatically and provides the necessary control functions. In normal operation the secondary computer's function is limited to display and monitor system functions.
System information, failures and warnings are output from the controllers to be used for display on ECAM and CFDS.
The environmental temperature control is performed via a temperature trim system which consists of all necessary valves, sensors and switches to control the air properties in the independent zones. It is controlled by both Air Conditioning System Controllers (ACSC). Each of the two air conditioning packs are controlled by its own independent ACSC.
Both ACSC's are in fully digital technics and incorporate, in addition to its control function, a Built In Test Equipment (BITE).
To further enhance reliability and get a high level of redundancy, both ACSC's are equipped with two identical lanes. In case of one lane failure the second lane takes over the entire control automatically and provides all functions.
System information, failures and warnings are outputs from the controllers to be used for display on ECAM and CFDS.
(1) Sub-Systems of the ECS
More specific information is available in the following chapters of the ECS:
More specific information is available in the following chapters of the ECS:
- Flow Control and Indicating (Ref. AMM D/O 21-51-00-00),
- Air Cooling System (Ref. AMM D/O 21-52-00-00),
- Pack Cooling Air Control (Ref. AMM D/O 21-53-00-00),
- Emergency Ram Air Inlet (Ref. AMM D/O 21-55-00-00),
- Pack Temperature Control (Ref. AMM D/O 21-61-00-00),
- Cockpit and Cabin Temperature Control (Ref. AMM D/O 21-63-00-00).
(2) Sub-Systems of the ECS
More specific information is available in the following chapters of the ECS:
More specific information is available in the following chapters of the ECS:
- Flow Control and Indicating (Ref. AMM D/O 21-51-00-00),
- Air Cooling System (Ref. AMM D/O 21-52-00-00),
- Pack Cooling Air Control (Ref. AMM D/O 21-53-00-00),
- Emergency Ram Air Inlet (Ref. AMM D/O 21-55-00-00),
- Pack Temperature Control (Ref. AMM D/O 21-61-00-00),
- Cockpit and Cabin Temperature Control (Ref. AMM D/O 21-63-00-00).
B. System Description of the ECS Control
The ECS controls the environment for the three independent zones (flight deck, two passenger zones) with a minimum of crew inputs. The only cockpit and cabin crew activated controls (on the overhead panel 30VU) are:
The crew inputs via these selectors and switches are to select the temperature, the airflow and to activate the zone trim system and the air conditioning packs. All other controls are fully automatic.
System malfunctions are automatically corrected. The failure information is stored in a non volatile memory and data is send to the System Data Aquisition Concentrator (SDAC) and Centralized Fault Display System (CFDS) for display, storage and pilot information.
The ECS controls the environment for the three independent zones (flight deck, two passenger zones) with a minimum of crew inputs. The only cockpit and cabin crew activated controls (on the overhead panel 30VU) are:
The crew inputs via these selectors and switches are to select the temperature, the airflow and to activate the zone trim system and the air conditioning packs. All other controls are fully automatic.
System malfunctions are automatically corrected. The failure information is stored in a non volatile memory and data is send to the System Data Aquisition Concentrator (SDAC) and Centralized Fault Display System (CFDS) for display, storage and pilot information.
The ECS controls the environment for the three independent zones (flight deck, two passenger zones) with a minimum of crew inputs. The only cockpit and cabin crew activated controls (on the overhead panel 30VU) are:
The crew inputs via these selectors and switches are to select the temperature, the airflow and to activate the zone trim system and the air conditioning packs. All other controls are fully automatic.
System malfunctions are automatically corrected. The failure information is stored in a non volatile memory and data is send to the System Data Aquisition Concentrator (SDAC) and Centralized Fault Display System (CFDS) for display, storage and pilot information.
The ECS controls the environment for the three independent zones (flight deck, two passenger zones) with a minimum of crew inputs. The only cockpit and cabin crew activated controls (on the overhead panel 30VU) are:
- the HOT AIR pushbutton switch,
- the COCKPIT temperature selector,
- the FWD CABIN temperature selector,
- the AFT CABIN temperature selector,
- the PACK FLOW selector,
- the PACK 1 pushbutton switch,
- the PACK 2 pushbutton switch.
The crew inputs via these selectors and switches are to select the temperature, the airflow and to activate the zone trim system and the air conditioning packs. All other controls are fully automatic.
System malfunctions are automatically corrected. The failure information is stored in a non volatile memory and data is send to the System Data Aquisition Concentrator (SDAC) and Centralized Fault Display System (CFDS) for display, storage and pilot information.
The ECS controls the environment for the three independent zones (flight deck, two passenger zones) with a minimum of crew inputs. The only cockpit and cabin crew activated controls (on the overhead panel 30VU) are:
- the HOT AIR pushbutton switch,
- the COCKPIT temperature selector,
- the FWD CABIN temperature selector,
- the AFT CABIN temperature selector,
- the ECON FLOW pushbutton switch,
- the PACK 1 pushbutton switch,
- the PACK 2 pushbutton switch.
The crew inputs via these selectors and switches are to select the temperature, the airflow and to activate the zone trim system and the air conditioning packs. All other controls are fully automatic.
System malfunctions are automatically corrected. The failure information is stored in a non volatile memory and data is send to the System Data Aquisition Concentrator (SDAC) and Centralized Fault Display System (CFDS) for display, storage and pilot information.
The ECS controls the environment for the three independent zones (flight deck, two passenger zones) with a minimum of crew inputs. The only cockpit and cabin crew activated controls (on the overhead panel 30VU) are:
- the HOT AIR pushbutton switch,
- the COCKPIT temperature selector,
- the FWD CABIN temperature selector,
- the AFT CABIN temperature selector,
- the PACK FLOW selector,
- the PACK 1 pushbutton switch,
- the PACK 2 pushbutton switch.
The crew inputs via these selectors and switches are to select the temperature, the airflow and to activate the zone trim system and the air conditioning packs. All other controls are fully automatic.
System malfunctions are automatically corrected. The failure information is stored in a non volatile memory and data is send to the System Data Aquisition Concentrator (SDAC) and Centralized Fault Display System (CFDS) for display, storage and pilot information.
(1) HOT AIR Pushbutton Switch
The HOT AIR pushbutton switch allows the cockpit crew to shut of the trim air flow by closing the trim air system.
The HOT AIR pushbutton switch allows the cockpit crew to shut of the trim air flow by closing the trim air system.
(2) COCKPIT, FWD CABIN and AFT CABIN Temperature Selectors
The COCKPIT, FWD CABIN and AFT CABIN temperature selectors allow the cockpit crew to select the cockpit, the FWD cabin and the AFT cabin temperature.
The COCKPIT, FWD CABIN and AFT CABIN temperature selectors allow the cockpit crew to select the cockpit, the FWD cabin and the AFT cabin temperature.
(3) PACK FLOW Selector
The PACK FLOW selector allows the cockpit crew to select 80%, 100% or 120% of the nominal airflow. In case of 80% selected air flow the Zone Controller (ZC) may increase the airflow up to 100% to satify the temperature demands.
The PACK FLOW selector allows the cockpit crew to select 80%, 100% or 120% of the nominal airflow. In case of 80% selected air flow the Zone Controller (ZC) may increase the airflow up to 100% to satify the temperature demands.
(4) PACK 1 and PACK 2 Pushbutton Switches
The PACK 1 and PACK 2 pushbutton switches allow the cockpit crew to switch the air conditioning packs on or off.
The PACK 1 and PACK 2 pushbutton switches allow the cockpit crew to switch the air conditioning packs on or off.
(5) HOT AIR Pushbutton Switch
The HOT AIR pushbutton switch allows the cockpit crew to shut of the trim air flow by closing the trim air system.
The HOT AIR pushbutton switch allows the cockpit crew to shut of the trim air flow by closing the trim air system.
(6) COCKPIT, FWD CABIN and AFT CABIN Temperature Selectors
The COCKPIT, FWD CABIN and AFT CABIN temperature selectors allow the cockpit crew to select the cockpit, the FWD cabin and the AFT cabin temperature.
The COCKPIT, FWD CABIN and AFT CABIN temperature selectors allow the cockpit crew to select the cockpit, the FWD cabin and the AFT cabin temperature.
(7) ECON FLOW pushbutton Switch
The ECON FLOW pushbutton switch allows the cockpit crew to select 80% or 100% of the nominal airflow. In case of 80% selected air flow the Zone Controller (ZC) may increase the airflow up to 100% to satify the temperature demands.
The ECON FLOW pushbutton switch allows the cockpit crew to select 80% or 100% of the nominal airflow. In case of 80% selected air flow the Zone Controller (ZC) may increase the airflow up to 100% to satify the temperature demands.
(8) PACK 1 and PACK 2 Pushbutton Switches
The PACK 1 and PACK 2 pushbutton switches allow the cockpit crew to switch the air conditioning packs on or off.
The PACK 1 and PACK 2 pushbutton switches allow the cockpit crew to switch the air conditioning packs on or off.
(9) HOT AIR Pushbutton Switch
The HOT AIR pushbutton switch allows the cockpit crew to shut of the trim air flow by closing the trim air system.
The HOT AIR pushbutton switch allows the cockpit crew to shut of the trim air flow by closing the trim air system.
(10) COCKPIT, FWD CABIN and AFT CABIN Temperature Selectors
The COCKPIT, FWD CABIN and AFT CABIN temperature selectors allow the cockpit crew to select the cockpit, the FWD cabin and the AFT cabin temperature.
The COCKPIT, FWD CABIN and AFT CABIN temperature selectors allow the cockpit crew to select the cockpit, the FWD cabin and the AFT cabin temperature.
(11) PACK FLOW Selector
The PACK FLOW selector allows the cockpit crew to select 80%, 100% or 120% of the nominal airflow. In case of 80% selected air flow the ACSC's may increase the airflow up to 100% to satify the temperature demands.
The PACK FLOW selector allows the cockpit crew to select 80%, 100% or 120% of the nominal airflow. In case of 80% selected air flow the ACSC's may increase the airflow up to 100% to satify the temperature demands.
(12) PACK 1 and PACK 2 Pushbutton Switches
The PACK 1 and PACK 2 pushbutton switches allow the cockpit crew to switch the air conditioning packs on or off.
The PACK 1 and PACK 2 pushbutton switches allow the cockpit crew to switch the air conditioning packs on or off.
3. Operation/Control and Indicating
Pack Temperature Control-System ** ON A/C NOT FOR ALL
Pack Temperature Control-System ** ON A/C NOT FOR ALL
Environmental Control System - Schematic ** ON A/C NOT FOR ALL
Environmental Control System - Schematic ** ON A/C NOT FOR ALL
Environmental Control System - Schematic ** ON A/C NOT FOR ALL
Environmental Control System - Schematic ** ON A/C NOT FOR ALL
Environmental Control System - Schematic ** ON A/C NOT FOR ALL
Pack Temperature Control-System ** ON A/C NOT FOR ALL Pack Temperature Control-System ** ON A/C NOT FOR ALL Environmental Control System - Schematic ** ON A/C NOT FOR ALL Environmental Control System - Schematic ** ON A/C NOT FOR ALL Environmental Control System - Schematic ** ON A/C NOT FOR ALL Environmental Control System - Schematic ** ON A/C NOT FOR ALL Environmental Control System - Schematic ** ON A/C NOT FOR ALL A. Operation of the Cockpit and Cabin Temperature Control
The temperature of the conditioned air, which is supplied to the individual zones, is either determined by the Zone Controller (ZC) or by the maximum capabilities of the system.
The system capacity limiting supply air-temperatures are only required for extreme operating conditions e.g. cooling the cabin on a very hot day or heating the cabin in a cold soaked airplane. Between these two extreme operating conditions the conditioned air temperature must be modulated to maintain a stable cabin temperature.
The pilot selects the desired cockpit and cabin temperatures on the temperature selectors within a range from +18 DEG.C (64.40 DEG.F) up to +30 DEG.C (86.00 DEG.F).
The zone controller determines from the input values of the:
The zone duct air temperature is normally limited from +8 DEG.C (46.40 DEG.F) to +50 DEG.C (122.00 DEG.F).
During full up/down operations these limits can be overridden when the cabin temperature exceeds the nominal zone temperature (+18 DEG.C up to +27 DEG.C). In this case the zone inlet duct limitations will extend from +2 DEG.C (35.60 DEG.F) to +70 DEG.C (158.00 DEG.F).
The pack temperature control will only satisfy the zone with demand for the coldest air.
The other two zones will receive additional heating from the trim air system so that the mix of the trim air and of the mix manifold air supply satisfy their zone duct-air temperature demands.
The trim air is bled from the ducting between the flow control valve and the primary heat exchanger from each air conditioning pack.
A check valve prevents pack to pack flow when one pack is shut down.
The pressure is reduced to 0.28 bar (4.0611 psi) in the trim pressure regulating valve to minimize noise transmission to the cabin, or the pressure is reduced to 0.14 bar (2.0305 psi) in case of early overheat condition.
The final zone supply air temperature regulation is accomplished by an additional heating flow through the individual trim air valves.
The temperature of the conditioned air, which is supplied to the individual zones, is either determined by the ACSC's or by the maximum capabilities of the system.
The system capacity limiting supply air-temperatures are only required for extreme operating conditions e.g. cooling the cabin on a very hot day or heating the cabin in a cold soaked airplane. Between these two extreme operating conditions the conditioned air temperature must be modulated to maintain a stable cabin temperature.
The pilot selects the desired cockpit and cabin temperatures on the temperature selectors within a range from +18 DEG.C (64.40 DEG.F) up to +30 DEG.C (86.00 DEG.F).
The ACSC determines from the input values of the:
The zone duct air temperature is normally limited from +8 DEG.C (46.40 DEG.F) to +50 DEG.C (122.00 DEG.F).
During extreme operations ( e.g. pull up / pull down) these limits can be overridden when the cabin temperature exceeds the nominal zone temperature (+18 DEG.C up to +27 DEG.C). In this case the zone inlet duct limitations will extend from +2 DEG.C (35.60 DEG.F) to +70 DEG.C (158.00 DEG.F).
The pack temperature control will only satisfy the zone with demand for the coldest air.
The other two zones will receive additional heating from the trim air system so that the mix of the trim air and of the mix manifold air supply satisfy their zone duct-air temperature demands.
The trim air is bled from the ducting between the flow control valve and the primary heat exchanger from each air conditioning pack.
A check valve prevents pack to pack flow when one pack is shut down.
The pressure is reduced to 0.28 bar (4.0611 psi) in the trim pressure regulating valve to minimize noise transmission to the cabin, or the pressure is reduced to 0.14 bar (2.0305 psi) in case of early overheat condition.
The final zone supply air temperature regulation is accomplished by an additional heating flow through the individual trim air valves.
The temperature of the conditioned air, which is supplied to the individual zones, is either determined by the Zone Controller (ZC) or by the maximum capabilities of the system.
The system capacity limiting supply air-temperatures are only required for extreme operating conditions e.g. cooling the cabin on a very hot day or heating the cabin in a cold soaked airplane. Between these two extreme operating conditions the conditioned air temperature must be modulated to maintain a stable cabin temperature.
The pilot selects the desired cockpit and cabin temperatures on the temperature selectors within a range from +18 DEG.C (64.40 DEG.F) up to +30 DEG.C (86.00 DEG.F).
The zone controller determines from the input values of the:
- temperature selectors,
- cabin sensors,
- duct sensors,
- mix manifold sensors,
The zone duct air temperature is normally limited from +8 DEG.C (46.40 DEG.F) to +50 DEG.C (122.00 DEG.F).
During full up/down operations these limits can be overridden when the cabin temperature exceeds the nominal zone temperature (+18 DEG.C up to +27 DEG.C). In this case the zone inlet duct limitations will extend from +2 DEG.C (35.60 DEG.F) to +70 DEG.C (158.00 DEG.F).
The pack temperature control will only satisfy the zone with demand for the coldest air.
The other two zones will receive additional heating from the trim air system so that the mix of the trim air and of the mix manifold air supply satisfy their zone duct-air temperature demands.
The trim air is bled from the ducting between the flow control valve and the primary heat exchanger from each air conditioning pack.
A check valve prevents pack to pack flow when one pack is shut down.
The pressure is reduced to 0.28 bar (4.0611 psi) in the trim pressure regulating valve to minimize noise transmission to the cabin, or the pressure is reduced to 0.14 bar (2.0305 psi) in case of early overheat condition.
The final zone supply air temperature regulation is accomplished by an additional heating flow through the individual trim air valves.
The temperature of the conditioned air, which is supplied to the individual zones, is either determined by the ACSC's or by the maximum capabilities of the system.
The system capacity limiting supply air-temperatures are only required for extreme operating conditions e.g. cooling the cabin on a very hot day or heating the cabin in a cold soaked airplane. Between these two extreme operating conditions the conditioned air temperature must be modulated to maintain a stable cabin temperature.
The pilot selects the desired cockpit and cabin temperatures on the temperature selectors within a range from +18 DEG.C (64.40 DEG.F) up to +30 DEG.C (86.00 DEG.F).
The ACSC determines from the input values of the:
- temperature selectors,
- cabin sensors,
- duct sensors,
- mix manifold sensors,
- altitude corrections,
- individual zone adjustments via FAP,
The zone duct air temperature is normally limited from +8 DEG.C (46.40 DEG.F) to +50 DEG.C (122.00 DEG.F).
During extreme operations ( e.g. pull up / pull down) these limits can be overridden when the cabin temperature exceeds the nominal zone temperature (+18 DEG.C up to +27 DEG.C). In this case the zone inlet duct limitations will extend from +2 DEG.C (35.60 DEG.F) to +70 DEG.C (158.00 DEG.F).
The pack temperature control will only satisfy the zone with demand for the coldest air.
The other two zones will receive additional heating from the trim air system so that the mix of the trim air and of the mix manifold air supply satisfy their zone duct-air temperature demands.
The trim air is bled from the ducting between the flow control valve and the primary heat exchanger from each air conditioning pack.
A check valve prevents pack to pack flow when one pack is shut down.
The pressure is reduced to 0.28 bar (4.0611 psi) in the trim pressure regulating valve to minimize noise transmission to the cabin, or the pressure is reduced to 0.14 bar (2.0305 psi) in case of early overheat condition.
The final zone supply air temperature regulation is accomplished by an additional heating flow through the individual trim air valves.
B. Operation of the Pack Temperature Control
The pack temperature control system operates from a source of pressurized air which is supplied from the engines, the APU or from a ground source.
The air is metered in the flow control valve to provide a constant volumetric flow regardless of the cabin altitude.
The nominal flow can be increased or decreased by cockpit command.
The metered flow is cooled in the primary heat exchanger using ambient ram air as a heat sink.
The flow of the ram air is regulated by the movable ram air inlet flaps to minimize the ram air flow while at the same time assuring an efficient heat transfer and thrust recovery.
In flight, ambient ram air pressure helps the fan to supply satisfactory flow.
For ground operation, the Air-Cycle Machine (ACM) fan provides the required ram air flow.
During take-off and landing, the ram air inlet is closed to avoid dirt ingestion and contamination of the heat exchangers.
After passing through the primary heat exchanger, a part of the bleed air flow is compressed by the ACM compressor where its pressure and temperature are raised and then cooled in the main heat exchanger using ram air as a heat sink.
This portion of the air flow enters the high pressure water seperator loop and in its first component, the reheater, it is cooled by the ACM turbine inlet air.
This cooling can bring the air temperature to below its dew point. Thus water condensation can start on the outlet side of the reheater and is then accelerated in the next component, the condenser, of the high pressure water seperator loop.
In the condenser, the air is cooled further by the ACM tubine-outlet air.
The air, which comes from the ACM turbine outlet, has a subzero temperature. This subzero temperature air cools the air in the condenser down to a sea level dew point of approximately 0 DEG.C (32.00 DEG.F). This makes sure that the dew point of the air, which is supplied to the mixer-unit, is lower than +10 DEG.C (50.00 DEG.F).
The +10 DEG.C (50.00 DEG.F) dew point will allow a maximum cabin air humdity without condensation in the mix manifold or cabin supply air ducting.
The condensed moisture is collected in the water extractor and sprayed on the ram inlet air side of the main heat exchanger to increase its cooling efficiency.
After the water extractor, the air passes through the reheater again where it increases in temperature and then enters the ACM turbine inlet.
In the ACM turbine, the high pressure air expends its kinetic energy. The temperature and the pressure decresase. This will cause additional condensation during ground operation and low altitude flight operation. This condensation will occur as snow.
The condenser is a tubular heat exchanger with a tube to tube distance, which is large enough, to prevent the snow from clogging the condenser.
The final pack temperature regulation takes place by mixing the ACM by-passed air with the turbine outlet air.
To achieve the zone demanded pack discharge-temperature, the pack controller modulates the by-pass valve and the ram air inlet flaps in a predetermined sequence. The sequence is a compromise between a minimized ram air flow while also maintaining adequate heat transfer rates and satisfactory pack air flow.
Additionally the by-pass valve always maintains a minimum ACM flow to keep the ACM idling during all operations.
In a full cooling mode, the ram air inlet flaps are fully open and the turbine by-pass valve is fully closed.
In a full heating mode, the ram air inlet flaps are nearly closed and the by-pass valve is fully open.
Between these two extreme conditions, the above mentioned schedule is in effect.
In the mixer unit, the pack discharge air is mixed with the cabin recirculation air. The combined air flow supplies the zone ducts where hot trim air is added individually for each of the three zones.
The air flow demand is selected by the flight crew with the flow selector which allows a flow setting of 80%, 100% and 120%.
The zone controller manipulates the flow between 80% and 100% if the zone duct temperature is limited at its high or low value. It transmits the determined flow demand to the pack controllers which modulate the flow servo of the flow control valve.
To achieve the zone demanded pack discharge-temperature, the pack controller modulates the by-pass valve and the ram air inlet flaps in a predetermined sequence. The sequence is a compromise between a minimizing ram air flow while also maintaining adequate heat transfer rates and satisfactory pack air flow.
Additionally the by-pass valve always maintains a minimum ACM flow to keep the ACM idling during all operations.
In a full cooling mode, the ram air inlet flaps are fully open and the turbine by-pass valve is fully closed.
In a full heating mode, the ram air inlet flaps are nearly closed and the by-pass valve is fully open.
Between these two extreme conditions, the above mentioned schedule is in effect.
In the mixer unit, the pack discharge air is mixed with the cabin recirculation air. The combined air flow supplies the zone ducts where hot trim air is added individually for each of the three zones.
The air flow demand is selected by the flight crew with the flow selector which allows a flow setting of 80% or 100%.
The zone controller manipulates the flow between 80% and 100% if the zone duct temperature is limited at its high or low value. It tranmits the determined flow demand to the pack controllers which modulate the flow servo of the flow control valve.
To achieve the zone demanded pack discharge-temperature, the ACSC modulates the by-pass valve and the ram air inlet flaps in a predetermined sequence. The sequence is a compromise between a minimizing ram air flow while also maintaining adequate heat transfer rates and satisfactory pack air flow.
Additionally the by-pass valve always maintains a minimum ACM flow to keep the ACM idling during all operations.
In a full cooling mode, the ram air inlet flaps are fully open and the turbine by-pass valve is fully closed.
In a full heating mode, the ram air inlet flaps are nearly closed and the by-pass valve is fully open.
Between these two extreme conditions, the above mentioned schedule is in effect.
In the mixer unit, the pack discharge air is mixed with the cabin recirculation air. The combined air flow supplies the zone ducts where hot trim air is added individually for each of the three zones.
The air flow demand is selected by the flight crew with the flow selector which allows a flow setting of 80% or 100%.
The ACSC manipulates the flow between 80% and 100% if the zone duct temperature is limited at its high or low value. It tranmits the determined flow demand to the ACSC's which modulate the flow servo of the flow control valve.
To achieve the zone demanded pack discharge-temperature, the ACSC modulates the by-pass valve and the ram air inlet flaps in a predetermined sequence. The sequence is a compromise between a minimizing ram air flow while also maintaining adequate heat transfer rates and satisfactory pack air flow.
Additionally the by-pass valve always maintains a minimum ACM flow to keep the ACM idling during all operations.
In a full cooling mode, the ram air inlet flaps are fully open and the turbine by-pass valve is fully closed.
In a full heating mode, the ram air inlet flaps are nearly closed and the by-pass valve is fully open.
Between these two extreme conditions, the above mentioned schedule is in effect.
In the mixer unit, the pack discharge air is mixed with the cabin recirculation air. The combined air flow supplies the zone ducts where hot trim air is added individually for each of the three zones.
The air flow demand is selected by the flight crew with the flow selector which allows a flow setting of 80%, 100% and 120%.
The ACSC manipulates the flow between 80% and 100% if the zone duct temperature is limited at its high or low value. It tranmits the determined flow demand to the ACSC's which modulate the flow servo of the flow control valve.
The pack temperature control system operates from a source of pressurized air which is supplied from the engines, the APU or from a ground source.
The air is metered in the flow control valve to provide a constant volumetric flow regardless of the cabin altitude.
The nominal flow can be increased or decreased by cockpit command.
The metered flow is cooled in the primary heat exchanger using ambient ram air as a heat sink.
The flow of the ram air is regulated by the movable ram air inlet flaps to minimize the ram air flow while at the same time assuring an efficient heat transfer and thrust recovery.
In flight, ambient ram air pressure helps the fan to supply satisfactory flow.
For ground operation, the Air-Cycle Machine (ACM) fan provides the required ram air flow.
During take-off and landing, the ram air inlet is closed to avoid dirt ingestion and contamination of the heat exchangers.
After passing through the primary heat exchanger, a part of the bleed air flow is compressed by the ACM compressor where its pressure and temperature are raised and then cooled in the main heat exchanger using ram air as a heat sink.
This portion of the air flow enters the high pressure water seperator loop and in its first component, the reheater, it is cooled by the ACM turbine inlet air.
This cooling can bring the air temperature to below its dew point. Thus water condensation can start on the outlet side of the reheater and is then accelerated in the next component, the condenser, of the high pressure water seperator loop.
In the condenser, the air is cooled further by the ACM tubine-outlet air.
The air, which comes from the ACM turbine outlet, has a subzero temperature. This subzero temperature air cools the air in the condenser down to a sea level dew point of approximately 0 DEG.C (32.00 DEG.F). This makes sure that the dew point of the air, which is supplied to the mixer-unit, is lower than +10 DEG.C (50.00 DEG.F).
The +10 DEG.C (50.00 DEG.F) dew point will allow a maximum cabin air humdity without condensation in the mix manifold or cabin supply air ducting.
The condensed moisture is collected in the water extractor and sprayed on the ram inlet air side of the main heat exchanger to increase its cooling efficiency.
After the water extractor, the air passes through the reheater again where it increases in temperature and then enters the ACM turbine inlet.
In the ACM turbine, the high pressure air expends its kinetic energy. The temperature and the pressure decresase. This will cause additional condensation during ground operation and low altitude flight operation. This condensation will occur as snow.
The condenser is a tubular heat exchanger with a tube to tube distance, which is large enough, to prevent the snow from clogging the condenser.
The final pack temperature regulation takes place by mixing the ACM by-passed air with the turbine outlet air.
To achieve the zone demanded pack discharge-temperature, the pack controller modulates the by-pass valve and the ram air inlet flaps in a predetermined sequence. The sequence is a compromise between a minimized ram air flow while also maintaining adequate heat transfer rates and satisfactory pack air flow.
Additionally the by-pass valve always maintains a minimum ACM flow to keep the ACM idling during all operations.
In a full cooling mode, the ram air inlet flaps are fully open and the turbine by-pass valve is fully closed.
In a full heating mode, the ram air inlet flaps are nearly closed and the by-pass valve is fully open.
Between these two extreme conditions, the above mentioned schedule is in effect.
In the mixer unit, the pack discharge air is mixed with the cabin recirculation air. The combined air flow supplies the zone ducts where hot trim air is added individually for each of the three zones.
The air flow demand is selected by the flight crew with the flow selector which allows a flow setting of 80%, 100% and 120%.
The zone controller manipulates the flow between 80% and 100% if the zone duct temperature is limited at its high or low value. It transmits the determined flow demand to the pack controllers which modulate the flow servo of the flow control valve.
To achieve the zone demanded pack discharge-temperature, the pack controller modulates the by-pass valve and the ram air inlet flaps in a predetermined sequence. The sequence is a compromise between a minimizing ram air flow while also maintaining adequate heat transfer rates and satisfactory pack air flow.
Additionally the by-pass valve always maintains a minimum ACM flow to keep the ACM idling during all operations.
In a full cooling mode, the ram air inlet flaps are fully open and the turbine by-pass valve is fully closed.
In a full heating mode, the ram air inlet flaps are nearly closed and the by-pass valve is fully open.
Between these two extreme conditions, the above mentioned schedule is in effect.
In the mixer unit, the pack discharge air is mixed with the cabin recirculation air. The combined air flow supplies the zone ducts where hot trim air is added individually for each of the three zones.
The air flow demand is selected by the flight crew with the flow selector which allows a flow setting of 80% or 100%.
The zone controller manipulates the flow between 80% and 100% if the zone duct temperature is limited at its high or low value. It tranmits the determined flow demand to the pack controllers which modulate the flow servo of the flow control valve.
To achieve the zone demanded pack discharge-temperature, the ACSC modulates the by-pass valve and the ram air inlet flaps in a predetermined sequence. The sequence is a compromise between a minimizing ram air flow while also maintaining adequate heat transfer rates and satisfactory pack air flow.
Additionally the by-pass valve always maintains a minimum ACM flow to keep the ACM idling during all operations.
In a full cooling mode, the ram air inlet flaps are fully open and the turbine by-pass valve is fully closed.
In a full heating mode, the ram air inlet flaps are nearly closed and the by-pass valve is fully open.
Between these two extreme conditions, the above mentioned schedule is in effect.
In the mixer unit, the pack discharge air is mixed with the cabin recirculation air. The combined air flow supplies the zone ducts where hot trim air is added individually for each of the three zones.
The air flow demand is selected by the flight crew with the flow selector which allows a flow setting of 80% or 100%.
The ACSC manipulates the flow between 80% and 100% if the zone duct temperature is limited at its high or low value. It tranmits the determined flow demand to the ACSC's which modulate the flow servo of the flow control valve.
To achieve the zone demanded pack discharge-temperature, the ACSC modulates the by-pass valve and the ram air inlet flaps in a predetermined sequence. The sequence is a compromise between a minimizing ram air flow while also maintaining adequate heat transfer rates and satisfactory pack air flow.
Additionally the by-pass valve always maintains a minimum ACM flow to keep the ACM idling during all operations.
In a full cooling mode, the ram air inlet flaps are fully open and the turbine by-pass valve is fully closed.
In a full heating mode, the ram air inlet flaps are nearly closed and the by-pass valve is fully open.
Between these two extreme conditions, the above mentioned schedule is in effect.
In the mixer unit, the pack discharge air is mixed with the cabin recirculation air. The combined air flow supplies the zone ducts where hot trim air is added individually for each of the three zones.
The air flow demand is selected by the flight crew with the flow selector which allows a flow setting of 80%, 100% and 120%.
The ACSC manipulates the flow between 80% and 100% if the zone duct temperature is limited at its high or low value. It tranmits the determined flow demand to the ACSC's which modulate the flow servo of the flow control valve.
C. Overall Air Cooling and Temperature Control
Environmental Control System - Schematic ** ON A/C NOT FOR ALL
Environmental Control System - Schematic ** ON A/C NOT FOR ALL
Environmental Control System - Schematic ** ON A/C NOT FOR ALL
Environmental Control System - Schematic ** ON A/C NOT FOR ALL
Environmental Control System - Schematic ** ON A/C NOT FOR ALL
The components of the different systems which make up the overall air cooling and temperature control are listed below:
Environmental Control System - Schematic ** ON A/C NOT FOR ALL Environmental Control System - Schematic ** ON A/C NOT FOR ALL Environmental Control System - Schematic ** ON A/C NOT FOR ALL Environmental Control System - Schematic ** ON A/C NOT FOR ALL Environmental Control System - Schematic ** ON A/C NOT FOR ALL (1) Flow Control and Indicating (Ref. AMM D/O 21-51-00-00)
- 1 - Flow Control Valve
- 2 - Pressure Sensor
- 3 - Mixer Flap Actuator
- 4 - Flow Selector
(2) Air Cooling System (Ref. AMM D/O 21-52-00-00)
- 5 - Air Cycle Machine
- 6 - Water Extractor
- 7 - Reheater
- 8 - Condenser
- 9 - Primary Heat Exchanger
- 10 - Main Heat Exchanger
- 11 - Water Injector
- 12 - Downstream Check Valve
(3) Pack Temperature Control (Ref. AMM D/O 21-61-00-00)
- 13 - Pack Controller
- 14 - Bypass Valve
- 15 - Anti-ice Valve
- 16 - Ram Air Inlet Actuator
- 17 - Pack Inlet-Pressure Sensor
- 18 - Comp. Discharge Temp. Sensor
- 19 - Comp. Overheat Sensor
- 20 - Water Extractor Temp. Sensor
- 21 - Pack Discharge Sensor
- 22 - Comp. Pneumatic Overheat Sensor
- 23 - Pack Outlet Pneumatic Sensor
(4) Cockpit and Cabin Temperature Control (Ref. AMM D/O 21-63-00-00)
- 24 - Trim Air Pressure Reg. Valve
- 25 - Pressure Switch
- 26 - Trim Air Check Valve
- 27 - Trim Air Valve
- 28 - Zone Controller
- 29 - Zone Temperature Sensor
- 30 - Duct Temperature Sensor
- 31 - Mixer Temperature Sensor
- 35 - Zone Temperature Selector
(5) Flow Control and Indicating (Ref. AMM D/O 21-51-00-00)
- 1 - Flow Control Valve
- 2 - Pressure Sensor
- 3 - Mixer Flap Actuator
- 4 - Flow Selector
(6) Air Cooling System (Ref. AMM D/O 21-52-00-00)
- 5 - Air Cycle Machine
- 6 - Water Extractor
- 7 - Reheater
- 8 - Condenser
- 9 - Primary Heat Exchanger
- 10 - Main Heat Exchanger
- 11 - Water Injector
- 12 - Downstream Check Valve
(7) Pack Temperature Control (Ref. AMM D/O 21-61-00-00)
- 13 - Pack Controller
- 14 - Bypass Valve
- 15 - Anti-ice Valve
- 16 - Ram Air Inlet Actuator
- 17 - Pack Inlet-Pressure Sensor
- 18 - Comp. Discharge Temp. Sensor
- 19 - Comp. Overheat Sensor
- 20 - Water Extractor Temp. Sensor
- 21 - Pack Discharge Sensor
- 22 - Comp. Pneumatic Overheat Sensor
- 23 - Pack Outlet Pneumatic Sensor
- 24 - Back Up Solenoid
(8) Cockpit and Cabin Temperature Control (Ref. AMM D/O 21-63-00-00)
- 25 - Trim Air Pressure Reg. Valve
- 26 - Pressure Switch
- 27 - Trim Air Check Valve
- 28 - Trim Air Valve
- 29 - Zone Controller
- 30 - Zone Temperature Sensor
- 31 - Duct Temperature Sensor
- 32 - Mixer Temperature Sensor
- 33 - Zone Temperature Selector
(9) Flow Control and Indicating (Ref. AMM D/O 21-51-00-00)
- 1 - Flow Control Valve
- 2 - Pressure Sensor
- 3 - Mixer Flap Actuator
- 4 - ECON FLOW Pushbutton Switch
(10) Air Cooling System (Ref. AMM D/O 21-52-00-00)
- 5 - Air Cycle Machine
- 6 - Water Extractor
- 7 - Reheater
- 8 - Condenser
- 9 - Primary Heat Exchanger
- 10 - Main Heat Exchanger
- 11 - Water Injector
- 12 - Downstream Check Valve
(11) Pack Temperature Control (Ref. AMM D/O 21-61-00-00)
- 13 - Pack Controller
- 14 - Bypass Valve
- 15 - Anti-ice Valve
- 16 - Ram Air Inlet Actuator
- 17 - Pack Inlet-Pressure Sensor
- 18 - Comp. Discharge Temp. Sensor
- 19 - Comp. Overheat Sensor
- 20 - Water Extractor Temp. Sensor
- 21 - Pack Discharge Sensor
- 22 - Comp. Pneumatic Overheat Sensor
- 23 - Pack Outlet Pneumatic Sensor
- 24 - Back Up Solenoid
(12) Cockpit and Cabin Temperature Control (Ref. AMM D/O 21-63-00-00)
- 25 - Trim Air Pressure Reg. Valve
- 26 - Pressure Switch
- 27 - Trim Air Check Valve
- 28 - Trim Air Valve
- 29 - Zone Controller
- 30 - Zone Temperature Sensor
- 31 - Duct Temperature Sensor
- 32 - Mixer Temperature Sensor
- 33 - Zone Temperature Selector
(13) Flow Control and Indicating (Ref. AMM D/O 21-51-00-00)
- 1 - Flow Control Valve
- 2 - Pack Inlet Pressure Sensor
- 3 - Differential Pressure Sensor
- 4 - Mixer Flap Actuator
- 5 - Flow Selector
(14) Air Cooling System (Ref. AMM D/O 21-52-00-00)
- 6 - Air Cycle Machine
- 7 - Water Extractor
- 8 - Reheater
- 9 - Condenser
- 10 - Primary Heat Exchanger
- 11 - Main Heat Exchanger
- 12 - Water Injector
- 13 - Downstream Check Valve
(15) Pack Temperature Control (Ref. AMM D/O 21-61-00-00)
- 14 - Air Conditioning System Controller (ACSC)
- 15 - Bypass Valve
- 17 - Ram Air Inlet Actuator
- 18 - Compressor Overheat Sensor
- 19 - Water Extractor Temp. Sensor
- 20 - Pack Outlet Temp. Sensor
- 21 - Pack Discharge Pressure Sensor
(16) Cockpit and Cabin Temperature Control (Ref. AMM D/O 21-63-00-00)
- 22 - Trim Air Pressure Reg. Valve
- 23 - Trim Air Overpressure Switch
- 24 - Trim Air Check Valve
- 25 - Trim Air Valve
- 26 - Cabin Temperature Sensor
- 27 - Duct Temperature Sensor
- 28 - Mixer Temperature Sensor
- 29 - Zone Temperature Selector
(17) Flow Control and Indicating (Ref. AMM D/O 21-51-00-00)
- 1 - Flow Control Valve
- 2 - Pack Inlet Pressure Sensor
- 3 - Differential Pressure Sensor
- 4 - Mixer Flap Actuator
- 5 - ECON FLOW Pushbutton Switch
(18) Air Cooling System (Ref. AMM D/O 21-52-00-00)
- 6 - Air Cycle Machine
- 7 - Water Extractor
- 8 - Reheater
- 9 - Condenser
- 10 - Primary Heat Exchanger
- 11 - Main Heat Exchanger
- 12 - Water Injector
- 13 - Downstream Check Valve
(19) Pack Temperature Control (Ref. AMM D/O 21-61-00-00)
- 14 - Air Conditioning System Controller (ACSC)
- 15 - Bypass Valve
- 17 - Ram Air Inlet Actuator
- 18 - Compressor Overheat Sensor
- 19 - Water Extractor Temp. Sensor
- 20 - Pack Outlet Temp. Sensor
- 21 - Pack Discharge Pressure Sensor
(20) Cockpit and Cabin Temperature Control (Ref. AMM D/O 21-63-00-00)
- 22 - Trim Air Pressure Reg. Valve
- 23 - Trim Air Overpressure Switch
- 24 - Trim Air Check Valve
- 25 - Trim Air Valve
- 26 - Cabin Temperature Sensor
- 27 - Duct Temperature Sensor
- 28 - Mixer Temperature Sensor
- 29 - Zone Temperature Selector