What is the primary function of the secondary section heat exchanger package?

The primary function of the secondary section heat exchanger package is to cool the supply air from the air cycle machine compressor to the turbine. This is essential for the effective operation of the air conditioning and pressurization systems in aircraft, as it helps maintain the correct temperature and pressure levels within various components.

By cooling the air from the compressor, this heat exchanger ensures that the turbine operates efficiently. If the air entering the turbine is too hot, it can lead to a decrease in turbine efficiency, potentially causing issues with the aircraft's environmental control system. The efficiency of the entire system relies on the proper functioning of this heat exchanger, which plays a crucial role in managing temperatures and ensuring optimal performance for air conditioning and cabin pressurization operations.