Hybrid Hydrogen-Helium Cryocooler for Low-Power 4K Cooling
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Solution Overview
Problem
Current cryocooler systems for achieving cryogenic temperatures are power-intensive, heavy, and complex, making them unsuitable for remote environments like space or on-orbit applications, and existing methods for cooling with liquid hydrogen are limited in temperature and consumable.
Innovation Solution
A hybrid cryocooler system that combines liquid hydrogen pre-cooling with a re-circulated compressed helium loop, where liquid hydrogen from a reservoir is expanded to cool helium, which is then used in a Joule-Thomson expansion to achieve temperatures between 4K to 10K, reducing power consumption and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a Stirling cryocooler is used to pre-cool gaseous helium to approximately 17 K, then cryogenic temperatures between 4K to 10K can be achieved, but the system requires significant electrical power (414 W) and has high weight (45 kg)
Solution Approach 1:
The patent combines liquid hydrogen expansion cooling with a closed-loop helium refrigeration circuit to create a hybrid system. The liquid hydrogen provides pre-cooling to the helium, reducing the electrical power needed for the Stirling cryocooler to achieve the same cryogenic temperatures.
Solution Approach 2:
The liquid hydrogen serves dual purposes: as a fuel source and as a cooling medium. By expanding liquid hydrogen through an expansion valve, the system utilizes the cold gas to pre-cool the helium loop, making the hydrogen serve both propulsion and thermal management functions.
2Temperature
If a Stirling cryocooler is used to pre-cool gaseous helium to approximately 17 K, then cryogenic temperatures between 4K to 10K can be achieved, but the system has high weight (45 kg)
Solution Approach 1:
The patent combines liquid hydrogen expansion cooling with a closed-loop helium refrigeration circuit to create a hybrid system. The liquid hydrogen provides pre-cooling to the helium, reducing the electrical power needed for the Stirling cryocooler to achieve the same cryogenic temperatures.
Solution Approach 2:
The liquid hydrogen serves dual purposes: as a fuel source and as a cooling medium. By expanding liquid hydrogen through an expansion valve, the system utilizes the cold gas to pre-cool the helium loop, making the hydrogen serve both propulsion and thermal management functions.
3Temperature
If liquid hydrogen is expanded into a gas for cooling, then cooling can be provided, but the temperature is limited to no less than 15 K and the liquid hydrogen is consumed
Solution Approach 1:
The system performs preliminary cooling of the helium using expanded liquid hydrogen before the helium enters the Stirling cryocooler. This pre-cooling action reduces the temperature burden on the helium, allowing the subsequent cooling stages to operate more efficiently and achieve lower temperatures.
Solution Approach 2:
The system recovers and re-circulates the helium in a closed-loop configuration, preventing its consumption. While liquid hydrogen is consumed during expansion, the helium is continuously reused, significantly reducing overall consumable requirements compared to open-loop systems.
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 hybrid system achieves high heat lift at cryogenic temperatures with lower power consumption and weight, enabling efficient cooling for devices like focal plane arrays without the complexity of traditional cryocoolers, and allows for simultaneous use of hydrogen as a fuel and cooling medium.
Implementation Method 1
Hydrogen from the reservoir is passed through an expansion valve, reducing the pressure of the hydrogen from a first, higher pressure, to a second, lower pressure
Implementation Method 2
The first hydrogen pre-cooler heat exchanger receives as a first input hydrogen at the second pressure. The first hydrogen pre-cooler heat exchanger receives as a second input helium included in the helium refrigeration circuit
Implementation Method 3
The gaseous helium is then used in a Joule-Thomson expansion to achieve temperatures between 4K to 10 K
Data Source
AI summary
Embodiments of the disclosed invention relate to providing cooling to instruments or other components. More particularly, hydrogen from a store is provided to pre-cool helium contained within a closed loop refrigeration circuit. Helium pre-cooled by the hydrogen, for example after expansion of the hydrogen in an expansion valve, is itself passed through an expansion valve, and applied to a heat load. The helium can be circulated through the refrigeration circuit using a compressor. The hydrogen used for pre-cooling the helium can be from a store of hydrogen that also provides fuel to a hydrogen consumer, for example for propulsion of a vehicle carrying the cooling system or for the production of electrical power. A hydrogen consumer can also be provided with hydrogen that has first been used to pre-cool the helium refrigeration circuit.