Airbus Avionic Cooling
 

Can anybody give some insight into this complicated system. Presumably its all down to avoiding condensation in the avionics area. B:uhoh: ut why are the "trigger"temperatures what they are?

It would help if you told which model you want info for, and even then, there are options, so all cooling systems aren't necessarily the same.

are you refering to the trigger temp that decides open or closed configuration?

Good point. A319/20/21

I'll do my best to explain.
As you know, the avionics compartment has a number of computers, and computers, when up and running, generate heat. The heat has to stay at a certain level to ensure the safe operation of the computers. Not unlike your average PC at home.
In 320 series the cooling is handled by a fan (there can be other configurations, I'm not sure). When the fuselage is cold enough the hot air from the computers is circulated in a "tube" along the fuselage. And as the fuselage is cold, it cools the air. When the fuselage warms, the cooling isn't effective enough, so the AEVC (the computer that controls the system) opens up an inlet and outlet valve on the sides of the fuselage and blows the air right through.
Don't have system schematic on hand, but I can try and look for one tomorrow. I only have a picture of 340 but that's different from 320.

Many thanks. Ive got a schematic from the MM.

These two valves only open on the ground! They are open at temps above about P2degC or so, depends on the wind.
Here in ARN we never see them open in the winter. It is a sign of spring when you hear the whoosh as they open.

FCOM
 

Gentlemen,

I respectfully refer you to Airbus FCOM 1.21.30. It will answer all your questions regarding this topic, I'm sure.



PantLoad

Many thanks for the feedback. I've got it sorted now. With regards to the FCOM reference- I've never known anything in this document shed light on anything technical. The diagram for the ventilation system is confusing at best.:ugh: