Air-Cooled Heat Exchangers (ACHEs) in the Aerospace Industry
Air-cooled heat exchangers play a critical role in aircraft, spacecraft, and aviation systems, where weight savings, reliability, and thermal efficiency are crucial. Unlike liquid-cooled systems, ACHEs use ambient air to dissipate heat, making them ideal for aerospace applications where minimizing fluid systems is advantageous.
Working Principle in Aerospace
- Heat transfer from hot fluids (fuel, oil, hydraulic fluid, or electronics coolant) to air via finned tubes or cold plates.
- Ram air (forward motion-induced airflow) or fan-assisted cooling provides airflow.
- Lightweight, compact designs to meet strict aerospace weight and space constraints.
Applications in Aerospace
A. Aircraft Engine & Oil Cooling
- Lubricating oil cooling for jet engines (prevents overheating).
- Fuel-cooled oil coolers (FCOCs) – Uses fuel as a heat sink before combustion.
- Turboprop & turbofan thermal management.
B. Avionics & Electronics Cooling
- Cooling radar systems, flight computers, and power electronics.
- Liquid-cooled cold plates with air-cooled radiators (for high-power systems).
C. Environmental Control Systems (ECS)
- Air-cycle machines (ACMs) – Cooling cabin air in commercial/military aircraft.
- Bleed air pre-coolers – Reduces temperature before entering the ECS.
D. Spacecraft & Hypersonic Vehicles
- Thermal protection for re-entry vehicles (heat dissipation in thin atmospheres).
- Satellite electronics cooling (radiative cooling in vacuum).
. Electric Aircraft & eVTOLs
- Battery thermal management (lithium-ion cooling for safety & efficiency).
- Electric motor & inverter cooling.
Advantages in Aerospace
Weight Reduction – Eliminates heavy liquid cooling systems.
No Leak Risks – Avoids fluid leaks in sensitive avionics.
High Reliability – Fewer moving parts than liquid-cooled systems.
Energy Efficiency – Uses ram air (free cooling in flight).
Maintenance-Free – No coolant refills or corrosion issues