Cabin Air Conditioning With Expanded Bleed Air Thermal Exchange
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Solution Overview
Problem
Conventional air conditioning systems for transport vehicles face challenges in minimizing engine bleed air impact on fuel consumption and performance, ensuring cabin temperature and pressure control across flight phases, and addressing contamination risks from engine-sourced air.
Innovation Solution
An air conditioning system that utilizes a bleed air source for both pneumatic and thermal energy, combined with external air, and includes a network of pipes and control valves to regulate airflow, featuring multiple heat exchangers and turbines to optimize temperature and pressure control, and emergency bypass modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bleed air is used as the source of conditioning air, then the cabin can be supplied with air at controlled pressure and temperature, but the impact on kerosene consumption and engine performance increases
Solution Approach 1:
The system segments the air supply function by using separate sources for different purposes: bleed air is used only for driving the turbomachine and providing thermal energy, while outside air provides the bulk of the conditioning air, thereby reducing the amount of bleed air needed and minimizing its impact on fuel consumption
Solution Approach 2:
The bleed air serves multiple functions: it drives the air cycle turbomachine compressor, provides thermal energy for heating the outside air, and maintains system pressure, thereby reducing the overall quantity of bleed air required compared to conventional single-purpose systems
2Reliability
If bleed air is used as the source of conditioning air, then the cabin can be supplied with air at controlled pressure and temperature, but the risk of contamination from engine air increases
Solution Approach 1:
The system separates the contamination source (engine bleed air) from the cabin air supply by using outside air as the primary source of conditioned air, while bleed air is restricted to driving the turbomachine and providing thermal energy only, thereby eliminating contamination risk to passengers
Solution Approach 2:
Outside air acts as an intermediary medium that receives thermal energy from the bleed air through heat exchangers and then supplies the cabin, thereby transferring the necessary thermal energy without transmitting contaminated engine air to the passenger compartment
3Temperature
If dynamic air is used to cool the bleed air and compressed air, then the air conditioning system can function, but the drag of the transport vehicle increases
Solution Approach 1:
The system performs preliminary cooling of the bleed air and compressed air using heat exchangers before the air enters the cabin, allowing for more efficient use of dynamic air and reducing the total quantity of dynamic air needed, thereby minimizing the increase in vehicle drag
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
Reduces drag, minimizes energy consumption, and eliminates the need for electric compressor drives while ensuring safe, controlled cabin conditions and air quality.
Implementation Method 1
at least one heat exchanger, called primary cooling exchanger, housed in said dynamic air circulation channel and comprising a primary circuit supplied by the air flow from said compressor in thermal interaction with a secondary circuit supplied by said dynamic air
Implementation Method 2
an air cycle turbomachine comprising at least one compressor and one turbine, called a power turbine, mechanically connected to each other
Implementation Method 3
said compressor comprising an air inlet fluidically connected to an external air intake and an air outlet adapted to be able to be fluidically connected by said network of pipes
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an air-conditioning system for a cabin (10) of an aircraft (80) comprising a bleed air source (12); a dynamic air circulation channel (13); a network of ducts and control valves; an air-cycle turbomachine comprising at least one compressor (3) and a power turbine (4) mechanically connected to one another; at least one primary heat exchanger (PHX) housed in said channel (13), characterised in that said network of ducts comprises a thermal power duct (53) suitable for being able to fluidly connect, upon operating at least one control valve (25, 21), said air outlet (4b) of said power turbine (4) and said dynamic air circulation channel (13) upstream of said primary exchanger (PHX) so that said bleed air expanded by said power turbine (4) can form a source of thermal energy for said dynamic air feeding said primary circuit of said primary exchanger (PHX).