Pack-and-A-half architecture for environmental control systems
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Solution Overview
Problem
Conventional pack-and-a-half environmental control system architectures for aircraft are too large for certain locations, requiring installation in alternative areas, and there is a need to reduce their size while maintaining performance.
Innovation Solution
The design includes a ram module with primary and secondary heat exchangers and a refrigeration module with an air cycle machine and condenser heat exchanger, connected by conduits, allowing for installation in two separate aircraft volumes, with features like bypass valves, recirculated air inlets, and compact mixers to condition and supply air efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If pack-and-a-half environmental control system architecture is used, then system size is reduced compared to two-pack architecture, but the system is still too large for certain aircraft locations such as underwing pack bays
Solution Approach 1:
The environmental control system is divided into separate modules (condenser heat exchanger module, air cycle machine module, ram module) that can be installed in different locations within the aircraft. The modules are connected by conduits, allowing distributed installation in available spaces rather than requiring a single large volume, thereby enabling installation in underwing pack bays and other previously inaccessible locations.
2Reliability
If conventional two-pack architecture is used, then redundancy is maintained, but system size and weight increase
Solution Approach 1:
The system combines redundancy with consolidation by using a single condenser heat exchanger module that can receive air from multiple sources (primary heat exchanger and recirculated air inlet), while maintaining the ability to operate with reduced capacity if one ram module fails. This merging approach achieves redundancy without duplicating the entire pack architecture, thereby reducing overall system weight.
3Volume of moving object
If pack-and-a-half architecture is used, then some space savings are achieved, but installation in alternative locations like tail cone increases system complexity
Solution Approach 1:
The modular architecture with standardized conduits and connections enables the system to be installed in multiple aircraft locations (underwing pack bays, tail cone, or other volumes) without requiring location-specific design modifications. The same basic configuration can adapt to different installation environments, reducing the complexity associated with alternative location installations.
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 configuration enables reduced system size, improved performance, and reduced weight, allowing for installation in smaller spaces, such as underwing pack bays, while maintaining redundancy and efficiency in air conditioning for the aircraft cabin.
Implementation Method 1
a primary heat exchanger that receives air from the aircraft engines and cools the received air using flow from a ram air inlet
Implementation Method 2
a secondary heat exchanger that receives the cooled air from the primary heat exchanger and further cools the received air using additional flow from the ram air inlet
Implementation Method 3
a condenser heat exchanger that conditions air received from turbines of the air cycle machine module to supply the conditioned air to a cabin of the aircraft
Data Source
AI summary
Environmental control system for aircraft are provided having a ram module having a primary heat exchanger and a secondary heat exchanger, a refrigeration module having an air cycle machine module and a condenser heat exchanger module, and at least one conduit fluidly connecting the ram module to the refrigeration module such that the ram module and the refrigeration module can be installed in two separate volumes of the aircraft.