Aircraft Air Conditioning Control via Variable Process Air Temperature
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Solution Overview
Problem
The operation of aircraft air conditioning systems adversely affects the efficiency and fuel consumption of aircraft in flight mode, with increased fuel consumption resulting from the need to provide a constant high temperature of process air and the inefficiency of cooling capacity control.
Innovation Solution
A method and system for controlling the aircraft air conditioning system by dynamically adjusting the temperature of the process air mass flow based on the operating state, incorporating variations in cooling air flow through the preheat exchanger and the state of ram air channel flaps and internal valves to optimize efficiency and reduce fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the process air temperature is maintained at a constant high temperature (ca. 200°C), then the air conditioning unit can operate reliably under various conditions, but the fuel consumption of the aircraft increases
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant temperature system to a dynamic variable temperature system. The process air temperature is no longer fixed at 200°C but varies dynamically based on the operating state of the air conditioning unit, allowing the system to adapt to different cooling demands and reduce fuel consumption while maintaining reliability.
Solution Approach 2:
The patent implements parameter changes by modifying the process air temperature parameter from a constant value to a variable value. The temperature is adjusted according to the operating state (detected via ram air channel flap position and internal valve state), enabling the system to optimize fuel consumption by supplying lower temperatures when full cooling capacity is not required.
2Productivity
If the cooling capacity of the air conditioning unit is increased by opening the ram air channel flaps to increase ambient air flow, then the cooling performance improves, but the fuel consumption of the aircraft increases
Solution Approach 1:
The patent implements feedback by using the detected operating state of the air conditioning unit (ram air channel flap position and internal valve state) to control the process air temperature. This closed-loop feedback mechanism allows the system to adjust the temperature based on actual cooling demands, avoiding unnecessary fuel consumption associated with maintaining high cooling capacity when not needed.
Solution Approach 2:
The patent applies preliminary action by detecting the operating state in advance and adjusting the process air temperature accordingly before the air conditioning unit actually requires full cooling capacity. This proactive adjustment prevents the system from operating at high fuel consumption levels when lower cooling demands exist.
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 allows for direct influence on aircraft efficiency and fuel consumption by varying the process air temperature, reducing the cooling air mass flow and trim air requirements, thereby optimizing fuel efficiency and utilizing cooling capacity reserves effectively.
Implementation Method 1
the process air is pre-cooled in a preheat exchanger by heat transfer to cooling air
Implementation Method 2
the process air is cooled as it flows through a heat exchanger unit by heat transfer to ambient air
Data Source
AI summary
A method for controlling an aircraft air conditioning system includes the steps of detecting an operating state of an air conditioning unit of the aircraft air conditioning system and controlling the temperature of a process air mass flow supplied to the air conditioning unit in dependence on the operating state of the air conditioning unit.