Expendable-Fluid Heat Pump Cycle for Low-Power Aircraft Cooling
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Solution Overview
Problem
Conventional vapor and air compression cycle cooling systems face challenges in high-energy applications such as high-energy lasers and high-speed aircraft, where they have limited electric or mechanical shaft power and inadequate heat sinking, leading to inefficient cooling and weight penalties due to large heat exchangers.
Innovation Solution
A compression cycle cooling system utilizing an expendable fluid that vaporizes to produce a pressurized fluid, driving a turbine to assist the compressor and reduce the required input power, with a backpressure control valve to regulate boiler pressure and maintain consistent boiling temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional vapor or air compression cycle cooling systems are used, then cooling function is provided, but the system requires large heat exchangers resulting in increased weight and size
Solution Approach 1:
The patent changes the thermal parameters by introducing an expendable fluid with specific heat capacity and phase change characteristics. This fluid absorbs heat during vaporization and releases it during condensation, enabling more efficient heat transfer with smaller heat exchanger surfaces, thus reducing weight while maintaining cooling capacity.
Solution Approach 2:
The patent utilizes phase transitions of the expendable fluid (vaporization and condensation) to enhance heat transfer efficiency. The fluid vaporizes to absorb heat from the system being cooled, then condenses to release heat to the ambient environment, allowing for compact heat exchanger design with reduced weight.
2Temperature
If conventional cooling systems are used in high-energy applications, then cooling is provided, but electric or mechanical shaft power is insufficient
Solution Approach 1:
The patent implements a self-service mechanism where the expendable fluid's phase change process generates mechanical work through a turbine, which then drives the compressor. This internal power generation reduces the external electric or mechanical shaft power required, making the system suitable for high-energy applications with limited power availability.
3Temperature
If conventional cooling systems are used in high-speed aircraft, then cooling function is provided, but heat sink capacity is insufficient and drag is high
Solution Approach 1:
The patent uses phase transitions of the expendable fluid to reject heat more efficiently. The fluid vaporizes to absorb heat from the aircraft systems, then condenses to release heat to the ambient air, providing sufficient heat rejection capacity with a more compact heat sink that creates less drag at high speeds.
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
The system achieves greater cooling capacity with reduced input power and minimizes the size and weight of the heat sink, enhancing efficiency and reducing drag in aircraft applications.
Implementation Method 1
a warm side heat exchanger that receives the heated high-pressure working fluid from the compressor and cools it with an expendable fluid (liquid or gas) that receives heat from the heated high-pressure working fluid and vaporizes it to produce a pressurized expendable fluid
Implementation Method 2
an expendable fluid (liquid or gas) that receives heat from the heated high-pressure working fluid and vaporizes it to produce a pressurized expendable fluid
Implementation Method 3
a turbine powered by the pressurized expendable fluid that assists the motor to drive the compressor
Implementation Method 4
a backpressure control valve configured to be coupled in series between the turbine and the warm side heat exchanger
Data Source
AI summary
A cooling system (40) with a compression cooling cycle for a working fluid, passes an expendable fluid through a warm side heat exchanger (22) to cause the expendable fluid to vaporize and thus absorb heat from the working fluid by way of latent heat or enthalpy of vaporization and then runs the vaporized expendable fluid through a turbine (34) that drives a compressor (14).