Core-Shell TiO2 Dielectric Nanofluids for Transformer Heat Dissipation

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Solution Overview

Problem

The reliability and lifetime of large power and distribution transformers are limited due to inadequate heat dissipation and thermal degradation of insulation materials, primarily caused by insufficient thermal conductivity in dielectric liquids, leading to hot spots and accelerated decomposition of solid insulating materials.

Innovation Solution

Development of core-shell TiO2 nanoparticles with an organofunctional silane shell, produced via sol-gel synthesis, which enhance dispersibility and stability in dielectric fluids, resulting in improved thermal conductivity and colloidal stability, forming optically transparent nanofluids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional dielectric liquids are used in transformers, then the system is simple and easy to manufacture, but thermal conductivity is insufficient leading to heat accumulation and reduced reliability

Engineering Contradiction:
Improvetransformer reliabilityVSAvoidheat dissipation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent uses composite nanoparticles consisting of a metal oxide core (such as TiO2, SiO2, or Al2O3) covered by an organofunctional silane shell. This core-shell composite structure combines the high thermal conductivity of metal oxides with the surface functionality of silane coatings, achieving enhanced heat dissipation while maintaining colloidal stability in dielectric liquids.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the physical and chemical parameters of dielectric liquids by dispersing nanoparticles with specific size distributions (typically 10-100 nm), surface functional groups, and concentrations (0.1-5 wt%). These parameter changes significantly improve thermal conductivity and heat dissipation capabilities without compromising electrical insulation properties.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If nanoparticles are added to dielectric liquids to improve thermal conductivity, then heat dissipation is enhanced, but colloidal stability deteriorates due to particle aggregation and precipitation

Engineering Contradiction:
Improvethermal conductivityVSAvoidcolloidal stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent applies local quality modification by creating a core-shell structure where the metal oxide core provides thermal conductivity while the organofunctional silane shell provides steric stabilization and surface functionality. This localized functional differentiation resolves the contradiction between enhancing thermal properties and maintaining colloidal stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The organofunctional silane shell acts as an intermediary layer between the metal oxide core and the dielectric liquid. This intermediate shell prevents direct aggregation of metal oxide particles while maintaining their thermal conductivity, thereby achieving both improved heat dissipation and colloidal stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If metal oxide nanoparticles are used to enhance thermal conductivity, then heat dissipation improves, but particle aggregation occurs reducing dispersibility and stability

Engineering Contradiction:
Improvethermal conductivityVSAvoiddispersibility
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent employs thin film technology by coating metal oxide nanoparticles with organofunctional silane shells of controlled thickness (typically 1-10 nm). These flexible thin films provide steric hindrance that prevents particle aggregation while maintaining good dispersibility in dielectric liquids, thus improving ease of operation.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent optimizes particle size distribution (10-100 nm), surface functional group composition, and nanoparticle concentration (0.1-5 wt%) to achieve maximum dispersibility. These parameter changes ensure that nanoparticles remain well-dispersed and stable in dielectric liquids while maintaining enhanced thermal conductivity.

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 new nanofluids provide enhanced thermal conductivity, increased transformer lifetime, and improved tensile strength of paper insulation, extending the service life of transformers from 40 to over 80 years.

Implementation Method 1

produced via sol-gel synthesis

Methodology Applied
Scientific EffectSol-gel synthesis: Sol

Implementation Method 2

heating an alcoholic solution comprising a soluble titanium precursor, an acid catalyst, a silane precursor, and/or water

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

enhance thermal conductivity, increasing transformer lifetime

Methodology Applied
Scientific EffectThermal conductivity enhancement: Conduction (thermal)

Implementation Method 4

enhance dispersibility and stability in dielectric fluids, resulting in improved thermal conductivity and colloidal stability

Methodology Applied
Scientific EffectDispersibility enhancement: Dispersion (of waves)

Data Source

PatentEP4648066A1Highly stable nano-liquid dielectric insulation
Publication Date: 2025.11.12 GENERAL ELECTRIC TECH GMBH
  • EP4648066A1 patent drawingFigure 1
  • EP4648066A1 patent drawingFigure 2
  • EP4648066A1 patent drawingFigure 3

AI summary

Nanoparticle compositions with enhancing dispersibility and long-term stability that can increase thermal conductivity of a dielectric fluid and improving insulation material lifetime, methods of manufacturing the nanoparticle compositions, and dielectric nanofluid compositions with the nanoparticles are provided herein. The nanoparticle compositions may include a metal oxide core and an organofunctional silane shell covering the TiO2 core, wherein the organofunctional silane shell is a structure represented by R1-Si(OR2)3.