What does the fuel recirculation system cool using fuel supplied to each engine?

The fuel recirculation system is designed to cool the Integrated Drive Generator (IDG) oil. In the A320 aircraft, the IDG is responsible for converting the mechanical energy from the engine into electrical energy to power the aircraft's systems. During this process, the IDG generates heat, which needs to be managed to ensure optimal performance and to prevent overheating.

The fuel recirculation system utilizes fuel from the aircraft's fuel tanks, which passes through the IDG and absorbs excess heat. This cooled fuel is then redirected back to the fuel tanks, ensuring both effective cooling of the IDG oil and maintaining the temperature of the fuel itself. This system is efficient because it leverages excess fuel to provide cooling without requiring separate cooling systems or additional fluids.

Other options, while related to the aircraft's operations, do not involve the cooling of the IDG oil through the fuel recirculation system. The FADEC (Full Authority Digital Engine Control) manages the engine's performance but does not have a direct cooling requirement linked to the fuel system. The PTU (Power Transfer Unit) is primarily concerned with providing hydraulic power, and the BSCU (Brake Control Interface Unit) manages braking systems, neither of which are cooled using the fuel supplied to