Thermal Energy Storage Units for Stable High-Temperature Calcination
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Solution Overview
Problem
Current thermal energy storage systems face challenges in efficiently storing and delivering thermal energy at varying temperatures, managing thermal runaway, and addressing the intermittent nature of variable renewable energy sources, while also being cost-effective and capable of rapid charging and discharging to meet industrial demands.
Innovation Solution
A thermal energy storage system integrated with a calcination process that utilizes a container with vertically oriented thermal storage units, dynamic insulation, and a controller for managing energy distribution based on weather and demand forecasts, coupled with a calciner to efficiently store and deliver high-temperature heat using a combination of electrical and thermal energy sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal energy storage systems use solid media with heaters for high-temperature storage, then the temperature of stored energy is improved, but thermal runaway and element failure occur due to non-uniform charging and discharging
Solution Approach 1:
The thermal storage system is divided into multiple independent thermal storage units (TSUs), each containing stacks of bricks with embedded heaters. This segmentation allows uniform heat distribution within each unit while enabling independent control to prevent thermal runaway. The modular structure ensures that if one unit experiences issues, others continue operating reliably.
Solution Approach 2:
Heaters are strategically positioned within the brick stacks of each TSU to create localized heating zones that ensure uniform temperature distribution throughout the solid media. This local quality approach addresses non-uniform charging by concentrating thermal energy where needed, preventing hot spots and thermal runaway while maintaining high storage temperatures.
2Adaptability or versatility
If variable renewable energy (VRE) is stored as thermal energy, then the flexibility of energy supply is improved, but the efficiency of energy storage and delivery is reduced
Solution Approach 1:
The system performs preliminary thermal energy storage during periods of high VRE generation when electricity is abundant and inexpensive. Thermal energy is stored in the solid media (bricks) during charging phases, converting excess electrical energy into stored thermal energy. This preliminary action allows the system to deliver energy efficiently during peak demand periods without energy losses associated with repeated charge-discharge cycles.
Solution Approach 2:
The thermal storage system maintains continuous useful action by storing energy as heat in solid media that retains thermal energy without degradation. Unlike electrochemical batteries that suffer from efficiency losses during multiple cycles, the thermal storage system preserves energy continuously in the brick stacks, enabling efficient delivery whenever needed while maintaining adaptability to VRE availability.
3Productivity
If conventional fossil fuel combustion is used for industrial heat, then the continuous supply of high-temperature heat is improved, but environmental pollution and global warming worsen
Solution Approach 1:
The system replaces the mechanical/chemical process of fossil fuel combustion with an electrical heating system using resistive heaters embedded in thermal storage units. This substitution eliminates combustion-related emissions (CO2, NOx, SOx) while maintaining the ability to supply continuous high-temperature heat for industrial processes like alumina calcination. The electrical heaters convert electricity directly to heat without combustion, preserving productivity while eliminating harmful emissions.
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 enables efficient storage and delivery of high-temperature thermal energy, mitigates thermal runaway, and optimizes charging and discharging to meet industrial demands, reducing costs and environmental impact while enhancing system longevity.
Implementation Method 1
each comprising stacks of bricks with heaters
Implementation Method 2
stores electrical energy in the form of thermal energy
Implementation Method 3
delivers the stored energy in a discharging mode. The discharged energy is in the form of hot air, hot fluids in general, steam
Data Source
AI summary
An energy storage system (TES) converts variable renewable electricity (VRE) to continuous heat at over 1000° C. Intermittent electrical energy heats a solid medium. Heat from the solid medium is delivered continuously on demand. Heat delivery via flowing gas establishes a thermocline which maintains high outlet temperature throughout discharge. The delivered heat which may be used for processes including power generation and cogeneration. In one application, the TES provides higher-temperature heat through non-combustible fluid to an alumina calcination system used to remove impurities or volatile substances and/or to incur thermal decomposition to a desired product.