Which component directly follows Heat Exchanger (Primary) in the PACK air flow path?

Which component directly follows Heat Exchanger (Primary) in the PACK air flow path?

• A. PreCooler
• B. Compressor
• C. Heat Exchanger (Secondary)
• D. ReHeater

Answer: (B)

In the PACK air flow path, the first job of the primary heat exchanger is to cool the bleed air by transferring its heat to ram air, bringing the temperature down to a level suitable for the next stage. The air then must be pressurized to the higher pressure required for the air cycle to operate effectively, which is accomplished by the compressor. After compression, the air is cooled again in the secondary heat exchanger and then reheated before it’s sent to the cabin. The other components fit at different points in the flow: a pre-cooler would typically come before the primary heat exchanger to reduce temperature further, the secondary heat exchanger comes after compression, and the reheater comes after that stage. So, the direct follower after the primary heat exchanger is the compressor.

In the PACK air flow path, the first job of the primary heat exchanger is to cool the bleed air by transferring its heat to ram air, bringing the temperature down to a level suitable for the next stage. The air then must be pressurized to the higher pressure required for the air cycle to operate effectively, which is accomplished by the compressor. After compression, the air is cooled again in the secondary heat exchanger and then reheated before it’s sent to the cabin. The other components fit at different points in the flow: a pre-cooler would typically come before the primary heat exchanger to reduce temperature further, the secondary heat exchanger comes after compression, and the reheater comes after that stage. So, the direct follower after the primary heat exchanger is the compressor.