AIR CONDITIONING -ZONE TEMP CTRL AND INDICATION -FLIGHT DECK FUNCTIONAL DESCRIPTION
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AIR CONDITIONING -ZONE TEMP CTRL AND INDICATION -CABIN ZONE FUNCTIONAL DESCRIPTION
General
The cabin temperature control on the air conditioning panel sets the master temperature value for all cabin areas. The low temperature value (C on the control) is 65F (18C). The high temperature value (W on the control) is 85F (29C).
The number of cabin areas will not always be the same as the number of temperature control zones. Each cabin area may have one or more temperature control zones. The number of cabin areas is set by the CSS configuration database. See the cabin services system section for more information about the configuration database (SECTION 23-39).
The cabin temperature screen on the cabin system control panel (CSCP) or on the cabin area control panels (CACP) lets you adjust the temperature in each cabin area. You can set the temperature in each area plus or minus 10F (6C) from the master temperature value set on the air conditioning panel. You cannot set the temperature in the cabin areas below 65F (18C) or above 85F (29C).
Cabin Zone Temperature Control
The CTCs calculate a zone target temperature for each temperature control zone. The zone target temperature is used in other calculations for the control of these components:
* Zone trim air modulating valves
*
Zone trim air PRSOV (backup control if the modulating valve fails open)
*
Second stage turbine bypass valve (A/C pack component)
*
Low limit valve (A/C pack component)
*
Ram air actuator (A/C pack component).
The CTCs use these inputs to calculate the zone target temperatures:
BEJ 001-008
* Airplane at cruise data from the FMCF of AIMS, auto comfort correction bias
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*
Selected master temperature from the CABIN TEMP control
*
Bias to the master temperature (|10F, 6C) from the CABIN TEMPERATURE screen.
The zone target temperatures shows on these screens:
*
Cabin temperature screen, CSCP/CACP
*
Air synoptic display
*
Air conditioning maintenance page.
BEJ 001-008
The airplane at cruise condition causes the CTCs to adjust the cabin temperature up. This function is called the auto comfort correction. The correction makes sure the cabin stays at a comfortable temperature when the airplane skin gets cold. The CTC configuration software (OPC) can make this function inactive.
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EFFECTIVITY BEJ ALL 21-61-00
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AIR CONDITIONING -ZONE TEMP CTRL AND INDICATION -CABIN ZONE FUNCTIONAL DESCRIPTION
Zone air temperature sensors send the CTCs actual compartment temperature data. The CTCs set the actual compartment temperatures equal to the average of elements 1 and 2. If there are two sensors in a temperature control zone, the appropriate CTC averages the data from both sensors.
If both elements of the zone air temperature sensor fails, the CTCs use the duct temperature sensors as an alternate. This is called the alternate mode. The alternate mode does not give the best control. The cabin area temperature may need adjustment to keep the temperature at a comfortable level.
The lavatory/galley ventilation system pulls cabin air across the zone air temperature sensors. If the lavatory/galley ventilation system is off, the CTCs use the alternate mode to calculate the necessary duct temperatures for all temperature control zones.
Zone Duct Temperature Control
The CTCs calculate a zone duct target temperature for each temperature control zone. The target temperature has a high and a low limit. The high limit is 160F (71C) and the low limit changes with altitude. These are the low limits:
*
35F (1.7C) when the airplane is less than 29,000 feet (8845 meters)
*
Decreases to 29F (-1.7C) when the airplane is at 31,000 feet (9455 meters)
*
Decreases to 21F (-6C) when the airplane is at 35,000 feet (10,675 meters) or above.
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The CTCs use zone duct temperature data to control the position of the trim air modulating valves. See the zone temperature control and indication -zone temperature calculation page in this section for more information about the calculation of the trim air modulating valve position and the calculation of the necessary A/C pack outlet temperature. The CTCs also use the data to control one or both of the trim air PRSOVs when a trim air modulating valve fails open. See the trim air pressure regulation and shutoff control section for more information about the control of the trim air PRSOV (SECTION 21-62). 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：777 AMM 飞机维护手册 空调 Air Conditioning(73)
