Vapor compression cycle with direct pumped two-phase cooling
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Solution Overview
Problem
Conventional cooling systems for aircraft, particularly those with composite components, face inefficiencies and weight issues due to the use of vapor compression cycles and refrigerants like R-134a, which are heavy and environmentally concerning, necessitating the development of more efficient and lightweight cooling solutions that can handle high temperatures and reduce environmental impact.
Innovation Solution
A vapor compression cycle with a single-fluid, two-phase cooling system that includes a cold sink thermally coupled to a heat load, a separator for separating liquid and vapor portions of the working fluid, and a cooling cycle comprising a vapor loop and a liquid loop, using refrigerants like 1,1,1,2-Tetrafluoroethane (R-134a) or 2,3,3,3-Tetrafluoropropene (R-1234yf), and incorporating features such as a compressor, condenser, and valves to manage the fluid phases efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional air cycle cooling is used, then cooling capability is provided, but it cannot withstand high temperatures and is unsuitable for composite components
Solution Approach 1:
The patent changes the working fluid parameters by using a two-phase liquid-vapor system instead of conventional single-phase air cooling. This allows the system to operate at lower temperatures suitable for composite components while maintaining effective cooling capability through phase change heat transfer.
Solution Approach 2:
The patent utilizes phase transitions of the working fluid between liquid and vapor states to achieve cooling. The working fluid evaporates to absorb heat from composite components and condenses to release heat, providing effective cooling at temperatures compatible with composite materials.
2Temperature
If conventional vapor compression cycle with R-134a is used, then sub-ambient cooling is achieved, but system weight increases and environmental impact worsens
Solution Approach 1:
The patent merges the liquid cooling and vapor compression cycles into a single integrated system using the same working fluid. The working fluid serves dual purposes: as a liquid coolant for direct cooling and as a vapor refrigerant for sub-ambient cooling, eliminating the need for separate systems and reducing overall weight.
Solution Approach 2:
The working fluid performs multiple functions within the system: it acts as both the liquid coolant in the liquid loop and the vapor refrigerant in the vapor compression cycle. This multi-functionality reduces the number of components needed and decreases system weight while maintaining sub-ambient cooling capability.
3Temperature
If conventional vapor compression cycle is used, then sub-ambient cooling is provided, but system size and complexity increase
Solution Approach 1:
The patent combines the liquid cooling loop and vapor compression cycle into a single integrated system sharing common components such as the working fluid, heat exchangers, and valves. This merging reduces the number of separate components and simplifies the overall system architecture while maintaining sub-ambient cooling capability.
Solution Approach 2:
Components such as the heat exchangers and valves serve dual functions in both the liquid cooling loop and vapor compression cycle, reducing the total number of components needed. The working fluid itself performs multiple roles, simplifying the system design and reducing complexity.
4Object-affected harmful factors
If carbon dioxide refrigerant is used, then environmental impact is reduced, but system weight increases substantially
Solution Approach 1:
The patent changes the physical state parameters of the working fluid by utilizing two-phase flow instead of single-phase gas. This allows the use of lighter working fluids like R-134a or R-1234yf in liquid-vapor form, achieving both weight reduction and acceptable environmental impact by leveraging phase change heat transfer efficiency.
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 solution enhances cooling efficiency, reduces system weight and complexity, and minimizes environmental impact by directly cooling sensitive components with a single fluid, addressing flow maldistribution issues and inefficiencies associated with two-phase flow, while being suitable for aircraft applications.
Implementation Method 1
the separator is arranged downstream from the cold sink as a downstream separator... the vapor portion and the liquid portion of the working fluid are separated by gravity in the separator
Implementation Method 2
A vapor form of the working fluid flows from the separator into the compressor
Implementation Method 3
the working fluid then flows to the condenser
Implementation Method 4
A liquid form of the working fluid flows from the separator into the pump and the working fluid is increased in pressure
Implementation Method 5
a cold sink thermally coupled to a heat load
Implementation Method 6
a valve... and then through the valve, and returned to the separator
Data Source
AI summary
Cooling systems include a cold sink thermally coupled to a heat load, a separator configured to separate liquid and vapor portions of a working fluid, and a cooling cycle having a vapor loop and a liquid loop, the cooling cycle having the working fluid configured to pass through both the vapor loop and the liquid loop. The vapor loop includes the separator, a compressor, a condenser, and a valve. A vapor form of the working fluid flows from the separator into the compressor, and the working fluid then flows to the condenser, and then through the valve, and returned to the separator. The liquid loop includes the cold sink, the separator, and a pump. A liquid form of the working fluid flows from the separator into the pump and the working fluid is increased in pressure and supplied to the cold sink and then returned to the separator.