Thermodynamic analysis of a new electric environmental control system with energy recovery turbine

Abstract

A new electric environmental control system for aircraft is investigated to promote the electrification of aircraft, focusing on energy recovery from the exhaust air. In this system, by setting a recovery turbine behind the cabin, the discharged energy can be collected from the exhaust air from the cabin to the exterior. We perform a thermo-dynamic cycle analysis, where the temperature, pressure and entropy are calculated at each position of the cycle by considering the pressure ratios of the compressors as variable parameters. From the results of cycle analysis, we obtain a T − s diagram, appropriate operating conditions for pressure ratios, an energy recovery ratio ∈, a coefficient of performance(COP), and heat transfer in heat exchangers. It is found that ∈ and COP in our system have maximum values at the tip point condition where the pressure ratio γ23 of air cycle machine compressor tends to unity and show better performance compared to the literature, where ∈ ～ 85% and COP ～ 0.965. In addition, it is found that the energy recovery ratio at the condition increases with decreasing altitude.

Keywords

• electric environmental control system
• energy recovery
• thermodynamic analysis
• pressure ratio
• recovery turbine