Thermal Energy Storage Using Silicon Phase Change Materials
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Solution Overview
Problem
Current thermal energy storage systems face challenges in achieving high efficiency and low cost due to complexities in thermal stability, material compatibility, and low thermal conductivity of phase change materials, limiting their applicability in large-scale energy storage for power plants, especially those using renewable energy sources which struggle with intermittency.
Innovation Solution
A thermal energy storage system utilizing high-temperature, high-thermal-conductivity phase change materials like aluminum-silicon alloys or elemental silicon, charged electrically through direct current or heaters, and releasing heat via conduction or radiation for efficient electricity generation, allowing for compact and cost-effective energy storage and release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If latent heat storage is used to achieve higher energy density, then system volume is reduced, but thermal stability and material compatibility become problematic
Solution Approach 1:
The patent changes the temperature parameter by using high-temperature phase change materials (above 400°C) instead of conventional low-temperature materials. This parameter change enables higher energy density while maintaining material stability through careful selection of materials that are stable at these elevated temperatures.
Solution Approach 2:
The patent employs composite material structures, particularly metal-organic frameworks (MOFs) combined with phase change materials, or ceramic-composite structures. These composites provide both the phase change functionality for high energy density and the structural stability needed for thermal reliability at high temperatures.
2Quantity of substance
If conventional phase change materials are used for latent heat storage, then energy density is improved, but thermal conductivity remains low
Solution Approach 1:
The patent uses composite materials such as metal matrices combined with phase change materials, or ceramic-composite structures. These composites provide both the phase change functionality for high energy density and the structural stability needed for thermal reliability at high temperatures.
Solution Approach 2:
The patent implements localized thermal conductivity enhancement by adding high-conductivity materials (such as metal fins, conductive coatings, or embedded heat transfer pathways) specifically at the heat transfer interfaces, while the bulk phase change material maintains its high latent heat properties. This local quality change improves thermal conductivity without compromising energy density.
3Productivity
If high-temperature materials are used for ultra-supercritical power plants, then efficiency is improved, but cost increases
Solution Approach 1:
The patent extracts the thermal energy storage function from the main power generation system, creating a separate, modular storage unit. This allows the use of high-temperature, high-efficiency materials only where absolutely necessary (in the storage medium), while the rest of the system can use more cost-effective materials, thereby reducing overall cost while maintaining high efficiency.
Solution Approach 2:
The patent divides the thermal energy storage system into modular segments or units that can be independently manufactured, tested, and assembled. This segmentation enables standardized production of high-temperature components, reducing manufacturing costs through economies of scale while maintaining the high efficiency benefits of advanced materials.
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 system achieves high round-trip efficiency and cost competitiveness for both fossil fuel and renewable energy power plants, enabling flexible energy management and reducing strain on machinery during peak demand, while minimizing footprint and operational costs.
Implementation Method 1
electrical circuitry for driving electrical current through the phase change material or at least one electrical heater used to convert electricity into heat stored in the phase change material
Implementation Method 2
utilizing electrically heated phase change material as the storage medium
Implementation Method 3
Heat is transferred from the thermal energy storage unit to the heat-to-electricity subsystem predominantly by radiation or conduction heat transfer
Implementation Method 4
Heat is transferred from the thermal energy storage unit to the heat-to-electricity subsystem predominantly by radiation or conduction heat transfer
Data Source
AI summary
System for storage of electricity in the form of thermal energy, and release of thermal energy during times of demand. The system includes a unit for containing at least one electrically conducting phase change material and electrical circuitry for driving electrical current through the phase change material to heat the phase change material into a molten state, or at least one electrical heater used to convert electricity into heat stored in the phase change material. Structure is provided for transferring heat in the phase change material to a working fluid such as steam or gas for electricity generation in a steam turbine or gas turbine, capable of generating supercritical fluids. Structure is also provided for transferring heat in the phase change material to a thermal energy to electrical energy conversion device. A suitable phase change material is elemental silicon or an aluminum-silicon alloy.