Integrated environmental control systems and methods for controlling environmental temperature of an enclosed space
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Solution Overview
Problem
Current aircraft cooling systems are inefficient, leading to high fuel consumption due to inadequate use of available heat sinks, high thermal resistance, and the need for active cooling systems, even when external air is cooler than the equipment being cooled.
Innovation Solution
Integration of loop heat pipes, vapor compression cycle machines, and skin heat exchangers with a hybrid system that includes a RAM-air subsystem and a ground cooling fan, allowing for smart management of heat sinks and reduced power consumption by optimizing heat transport and exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If vapor compression cycle systems are used to cool compartments, then cooling capability is provided, but fuel consumption increases
Solution Approach 1:
The system uses the aircraft's own motion through the air (ram air) as the cooling mechanism during flight, eliminating the need for additional fuel-consuming cooling systems. The kinetic energy of the aircraft itself serves the cooling function.
Solution Approach 2:
The system changes the operational parameters of cooling based on flight conditions. During flight, it utilizes the high-velocity ram air for efficient heat rejection, while on the ground it switches to alternative cooling modes, optimizing fuel consumption across different operational states.
2Temperature
If cooling systems operate during all flight phases, then continuous cooling is provided, but fuel penalty increases
Solution Approach 1:
The cooling system dynamically adapts its operation based on flight phase and external conditions. It is most effective during cruise flight when ram air availability is highest, and can be reduced or modified during takeoff, landing, and ground operations, optimizing the balance between cooling performance and fuel consumption.
Solution Approach 2:
The system operates periodically based on flight phases, utilizing the most efficient cooling mode during cruise flight when ram air is abundant, and switching to less efficient or alternative modes during other phases, creating a periodic operation pattern that minimizes overall fuel penalty.
3Device complexity
If thermal resistance between equipment and heat sink is high, then cooling system is simpler, but active cooling systems are required even when external air is cooler
Solution Approach 1:
The system introduces a heat exchanger as an intermediary device between the equipment and the ram air heat sink. This heat exchanger provides a low thermal resistance pathway for heat transfer, enabling efficient passive cooling during flight without requiring additional active cooling systems.
Solution Approach 2:
The system replaces active mechanical cooling systems (fans, pumps) with a passive heat rejection mechanism that utilizes the aircraft's motion through the air. The kinetic energy of the aircraft substitutes for mechanical work that would otherwise be required to force air through heat exchangers.
4Ease of operation
If heat sinks are not fully utilized, then system operation is simpler, but fuel consumption increases
Solution Approach 1:
The system incorporates sensors and control logic that continuously monitor external air temperature, aircraft velocity, and thermal loads. This feedback enables the system to optimize heat rejection to the ram air heat sink in real-time, maximizing the utilization of available cooling capacity and minimizing fuel consumption.
Solution Approach 2:
The ram air heat rejection system serves multiple functions: it cools electronic equipment, cools cabin air, and can potentially provide thrust augmentation. This multi-functionality ensures full utilization of the heat sink capability, reducing the need for separate cooling systems and minimizing overall fuel consumption.
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 minimizes fuel penalty by effectively utilizing available heat sinks, reducing thermal resistance, and enabling efficient cooling with lower power consumption across various aircraft operations, while also allowing heat to be reused for heating or ice protection.
Implementation Method 1
a loop heat pipe (LHP) heat exchange subsystem having a closed loop heat exchange fluid circuit in heat-exchange relationship with the enclosed space
Implementation Method 2
skin heat exchangers, such as a LHP condenser skin heat exchanger (SHX)
Implementation Method 3
a vapor compression cycle machine (VCM) subsystem having a VCM fluid circuit comprising a compressor, an evaporator and a condenser
Data Source
AI summary
Environmental control systems and methods to control environmental temperature of an enclosed space by integrating a passive heat exchange subsystem (e.g., a loop heat pipe (LHP) heat exchange subsystem) having a closed loop heat exchange fluid circuit in heat-exchange relationship with the enclosed space for providing environmental temperature control therewithin, a RAM-air subsystem having a RAM-air circuit for circulating RAM cooling air, and a vapor compression cycle machine (VCM) subsystem having a VCM fluid circuit having a compressor, an evaporator, a condenser and an expansion valve.