Cabin Outflow Air Energy Optimized Pressurizing System
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Solution Overview
Problem
Current aircraft environmental control systems waste energy due to inefficiencies in cabin pressurization and air conditioning, particularly when there is a mismatch between main engine operating conditions and cabin needs, leading to high power consumption and complexity.
Innovation Solution
A pressurization system that utilizes ram air and engine fan air, boosted by a cabin outflow air turbine, and cooled by its exhaust, eliminating the need for additional power draw and ram air for cooling, with a configuration that includes a compressor, turbines, and heat exchangers to efficiently manage air pressure and temperature for cabin pressurization and air conditioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If main engine bleed air is used to pressurize the cabin, then the system can be compact and elegant, but the energy consumption is high due to mismatch between engine operating conditions and cabin pressurization needs
Solution Approach 1:
The system divides the pressurization function into two independent components: a cabin pressurization compressor driven by engine fan air, and a separate air conditioning system. This segmentation allows each component to operate independently and efficiently under different flight conditions, eliminating the energy waste from mismatched operation while maintaining system compactness.
Solution Approach 2:
The engine fan air is utilized for dual purposes: it drives the pressurization compressor and also serves as the cooling source for the air conditioning system. This multi-functionality reduces overall energy consumption by maximizing the utility of available engine resources across different flight phases.
2Use of energy by moving object
If cabin air compressors are used to pressurize ambient air, then energy waste is reduced, but the compressor is less efficient and requires heavy motors and power electronics
Solution Approach 1:
The system replaces electrically driven compressors with a mechanically driven compressor that is directly coupled to the engine fan air turbine. This substitution eliminates the need for heavy electric motors and power electronics, reducing weight while maintaining efficient energy transfer from the engine to the pressurization system.
Solution Approach 2:
The pressurization compressor is merged with the air conditioning turbine on a common shaft, creating an integrated unit that utilizes engine fan air for both pressurization and cooling purposes. This combination eliminates the need for separate electric motors, reducing overall system weight while improving energy efficiency.
3Ease of operation
If electrically driven CAC is used, then pressurization can be controlled, but the system requires heavy motors, power electronics, and continuous cooling
Solution Approach 1:
The system uses engine fan air to directly drive the pressurization compressor, eliminating the need for external electric motors and power electronics. The engine's existing airflow and pressure systems are harnessed to perform the pressurization function, reducing system complexity while maintaining controllability through engine parameter management.
4Volume of moving object
If traditional pneumatic systems are used, then the system can be compact, but a good portion of energy is wasted due to mismatch between engine conditions and cabin needs
Solution Approach 1:
The system dynamically adapts to different flight conditions by utilizing engine fan air that varies with engine thrust settings. As engine power changes during flight, the available fan air automatically adjusts to match cabin pressurization and air conditioning demands, eliminating energy waste from static system configurations while maintaining compactness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in approximately 2% mission fuel burn savings by reducing power consumption and eliminating the need for ram air cooling, while maintaining cabin air temperature and air conditioning efficiency, and allows for all-electric APU operation during various flight phases.
Implementation Method 1
a first turbine that is on a common shaft with the first compressor and wherein the first turbine receives the bleed air
Implementation Method 2
a main heat exchanger (hot side) downstream of the first compressor and the first turbine
Implementation Method 3
a second turbine downstream of the internal environment; the main heat exchanger (cold side) is downstream of the second turbine; a generator that is on a common shaft with the second turbine
Data Source
AI summary
A pressurization system includes a first compressor that receives a ram air, a fan air, or engine air; a first turbine that is on a common shaft with the first compressor and wherein the first turbine receives an engine air; a main heat exchanger downstream of the first compressor and the first turbine; an internal environment suitable for human occupants and downstream of the main heat exchanger; a second turbine downstream of the internal environment; the second turbine may be on the common shaft with the first compressor and first turbine; or a generator downstream of the second turbine; a motor downstream of the generator; and wherein the motor drives the first compressor.