Smooth-Bore LCP Cryostat for Long-Distance HTS Cable

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Solution Overview

Problem

Current high temperature superconductor (HTS) power cable systems face inefficiencies due to metallic alloy cryostats, including thermal inefficiency, electrical conductivity, mechanical challenges, and limitations in long-distance deployment, leading to increased costs and complexity.

Innovation Solution

A superconducting cable system utilizing a liquid crystal polymer (LCP) cryostat with a smooth bore design, which minimizes thermal expansion, reduces pressure losses, and allows for continuous manufacturing and reeling, thereby enabling long-distance HTS power cable deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If corrugated metallic cryostats are used to mechanically resist external loading and support HTS cable, then structural strength is improved, but pressure losses in cryogenic fluid flow increase significantly

Engineering Contradiction:
Improvestructural strengthVSAvoidpressure losses
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent changes the geometric parameters of the cryostat by using a smooth-bore design instead of corrugated profile, and selects materials (carbon fibre composite or Invar alloy) with different mechanical properties that can achieve structural strength without the pressure losses associated with corrugated metallic designs

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials, specifically carbon fibre reinforced polymer (CFRP) or Invar alloy, to achieve the required structural strength while maintaining a smooth-bore configuration that minimizes pressure losses in cryogenic fluid flow

Inventive Principle:
Principle #40Composite materials

2Reliability

If independent dielectric insulation layers are added to HTS power cable to ensure electrical insulation, then electrical insulation is improved, but outer diameter of the cable increases

Engineering Contradiction:
Improveelectrical insulationVSAvoidouter diameter
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the dielectric insulation function with the cryostat structure by forming the cryostat from electrically insulating materials (carbon fibre composite or Invar alloy), eliminating the need for separate dielectric insulation layers and thereby reducing the overall cable outer diameter

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cryostat structure is designed to serve multiple functions simultaneously: providing mechanical strength, containing cryogenic fluid, and providing electrical insulation, thereby eliminating redundant components and reducing cable diameter

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Quantity of substance

If larger diameter cryostats are used to host multi-layered HTS conductors and sufficient cryogenic fluid, then mass flow rate is improved, but radiative heat ingress increases

Engineering Contradiction:
Improvemass flow rateVSAvoidradiative heat ingress
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the cryostat diameter parameter to the minimum required size, allowing adequate cryogenic fluid flow while minimizing the surface area exposed to radiative heat ingress from the external environment

Inventive Principle:
Principle #35Parameter changes

4Loss of energy

If smooth-bore stainless steel cryostats are used to reduce turbulence and pressure losses, then pressure losses are reduced, but thermal contraction requires multiple expansion joints

Engineering Contradiction:
Improvepressure lossesVSAvoidexpansion joints
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent changes the material parameter by selecting Invar alloy or carbon fibre composite with low thermal expansion coefficients, allowing the cryostat to accommodate thermal contraction without requiring multiple expansion joints while maintaining smooth-bore configuration for reduced pressure losses

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The use of carbon fibre composite or Invar alloy provides a material solution that combines low thermal expansion with high structural integrity, enabling long-distance cryostat sections without expansion joints

Inventive Principle:
Principle #40Composite materials

5Strength

If metallic alloy cryostats are used to provide mechanical strength and containment, then structural strength is improved, but thermal insulation efficiency deteriorates

Engineering Contradiction:
Improvestructural strengthVSAvoidthermal insulation efficiency
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent uses carbon fibre reinforced polymer (CFRP) composite material which provides high structural strength while having inherently low thermal conductivity, thereby improving thermal insulation efficiency compared to metallic alloys

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material selection from high-conductivity metallic alloys to low-conductivity composite materials or Invar alloy, achieving the required structural strength with superior thermal insulation properties

Inventive Principle:
Principle #35Parameter changes

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 LCP cryostat system enhances thermal insulation, reduces heat ingress, and decreases the number of insulation layers, allowing for longer operational lengths and lower costs, making long-distance HTS power cable deployment economically and technically feasible.

Implementation Method 1

the liquid crystal polymer cryostat which minimises thermal expansion

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The LCP cryostat system enhances thermal insulation, reduces heat ingress

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

reduces pressure losses, and allows for continuous manufacturing and reeling, thereby enabling long-distance HTS power cable deployment

Methodology Applied
Scientific EffectTurbulence: Turbulence

Data Source

PatentEP4184531B1A superconducting cable system
Publication Date: 2024.11.20 SUPERNODE LTD
  • EP4184531B1 patent drawingFigure 1
  • EP4184531B1 patent drawingFigure 2
  • EP4184531B1 patent drawingFigure 3

AI summary

The present invention provides a superconducting cable system designed to facilitate long distance superconducting, the cable system including at least one inner cryostat containing a supply of cryogenic fluid and at least one superconductor extending longitudinally of the inner cryostat and in thermal communication with the cryogenic fluid, the inner cryostat comprising a liquid crystal polymer.