Transient investigation of a parallel vapor compression cycle for electric aircraft

The aviation industry faces the challenge of balancing emission reduction with the increasing demand for passenger flights. Electric aircraft offer a promising solution by eliminating emissions during flight, but their components necessitate an efficient thermal management system to achieve the restricted operating temperatures. A vapor compression cycle presents a viable approach to maintain component temperatures near or below ambient levels, even at hot ground-level temperatures. By using parallel evaporators directly connected to the electric components, multiple heat sources across an aircraft can be addressed. Despite its potential, the impact of such a system on aircraft performance remains unexplored, representing a crucial research area for future aircraft generations. To investigate this, an experimental test rig has been constructed to demonstrate the cooling system’s feasibility with the refrigerant R1336mzz(Z) and to validate a transient simulation model in MATLAB Simulink. The effect of additional drag, mass, and power consumption is analyzed over a flight mission. All factors are combined into a single objective parameter - the additional thrust requirement of the aircraft - derived from flight physics. The vapor compression cycle consistently outperforms a comparable liquid cooling cycle for all examined maximum component temperatures up to 70 ° C . A temperature lift of 40 K is identified as optimal, minimizing drag and outweighing the power increase due to the compressor. The studied vapor compression cycle achieves an airflow-dependent cooling capacity of up to 60 kW kg -1 s and a mass-dependent cooling capacity of 0 . 6 kW kg -1 , highlighting its effectiveness and potential for enhancing electric aircraft performance. • Direct evaporative cooling for parallel power electronics validated experimentally. • Vapor compression cycle cooling outperforms liquid systems up to 70 ° C • Saves up to 60% of additional thrust required by liquid cooling systems. • Drag reduction outweighs the increase in power consumption due to the compressor.