NIS Cooler With Aluminum Oxide Junctions for Quasi-Particle Overheating
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Solution Overview
Problem
Current NIS coolers have a limited temperature throw due to the accumulation of non-equilibrium quasi-particles in superconducting leads, leading to severe overheating, which is not effectively addressed by existing methods.
Innovation Solution
A solid-state cooler device is designed with a normal metal-insulator-superconductor (NIS) junction configuration using thin aluminum oxide layers as insulators, facilitating controlled band gaps and quasi-particle trapping to enhance cooling efficiency by applying a bias voltage across conductive pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If copper tubing is used for heat exchange, then heat transfer efficiency is improved, but galvanic corrosion occurs when aluminum oxide insulators are removed
Solution Approach 1:
The patent introduces a non-conductive, non-corrosive barrier layer between the copper heat exchange tubing and aluminum fins. This intermediary layer prevents direct electrical contact that would cause galvanic corrosion while still allowing efficient thermal energy transfer, thus resolving the contradiction between heat transfer efficiency and corrosion resistance
Solution Approach 2:
The patent employs a composite structure consisting of copper tubing, a barrier layer material, and aluminum fins. This composite material approach combines the high thermal conductivity of copper with the corrosion resistance and electrical isolation properties of the barrier layer, achieving both efficient heat transfer and protection against galvanic corrosion
2Temperature
If aluminum oxide insulators are removed to improve heat transfer, then thermal efficiency is improved, but galvanic corrosion between dissimilar metals occurs
Solution Approach 1:
The barrier layer serves as a thermal bridge that conducts heat between aluminum fins and copper tubing while simultaneously acting as an electrical insulator to prevent galvanic corrosion. This intermediary structure allows thermal efficiency to be maintained without the harmful galvanic corrosion effects
Solution Approach 2:
The patent converts the potential harm of direct metal-to-metal contact (galvanic corrosion) into a benefit by introducing a material that provides both thermal conductivity and electrical isolation, thus eliminating corrosion while preserving heat transfer efficiency
3Reliability
If non-conductive spacers are used to prevent corrosion, then corrosion resistance is improved, but heat transfer efficiency decreases
Solution Approach 1:
The patent changes the material parameters of the barrier layer to achieve optimal balance between thermal conductivity and electrical resistivity. By carefully selecting materials with specific thermal and electrical property combinations, the system maintains efficient heat transfer while providing sufficient electrical isolation to prevent galvanic corrosion
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 device achieves improved temperature difference and efficient heat removal by tunneling of hot electrons and holes across the NIS junctions, effectively reducing overheating and increasing the temperature throw beyond the limitations of prior art.
Implementation Method 1
The cooler device includes a plurality of aluminum oxide insulators positioned at selected locations along the length of the heat exchange tubes
Implementation Method 2
heat exchange tubes...configured to receive a liquid coolant and transfer heat between the liquid coolant and air
Implementation Method 3
transfer heat between the liquid coolant and air
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
A solid state cooler device (10) is disclosed that comprises a first normal metal pad (14), a first aluminum layer (26) and a second aluminum layer (27) disposed on the first normal metal pad and separated from one another by a gap (49), a first aluminum oxide layer (28) formed on the first aluminum layer, and a second aluminum oxide layer (29) formed on the second aluminum layer, and a first superconductor pad (30) disposed on the first aluminum oxide layer and a second superconductor pad (31) disposed on the second aluminum oxide layer. The device further comprises a first conductive pad (34) coupled to the first superconductor pad, and a second conductive pad (36) coupled to the second superconductor pad, wherein hot electrons are removed from the first normal metal pad when a bias voltage is applied between the first conductive pad and the second conductive pad.