Brick Thermal Storage with Deep-Discharge Heat Delivery
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Solution Overview
Problem
Existing thermal energy storage systems face challenges in efficiently storing and delivering thermal energy from variable renewable energy sources due to high costs, non-uniform temperature distribution leading to thermal runaway, and inefficiencies in charging and discharging processes, particularly in systems using solid media.
Innovation Solution
A thermal energy storage system utilizing vertically oriented thermal storage units with bricks and heaters, incorporating elongate channels for turbulent flow and radiation chambers, along with a blower for air circulation, and a controller for managing energy distribution based on weather and demand forecasts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thermal energy is stored in solid media using conventional methods, then energy storage capacity is achieved, but non-uniform temperature distribution occurs leading to thermal runaway
Solution Approach 1:
The thermal storage system is divided into multiple independently controllable heater zones and brick stacks. Each zone can be heated separately with its own heater and controller, allowing localized temperature management. This segmentation prevents thermal runaway by isolating temperature anomalies to specific zones rather than affecting the entire storage mass.
Solution Approach 2:
Different regions of the thermal storage system are assigned different heating characteristics. Heaters are positioned at specific locations (e.g., bottom, sides, top) of brick stacks to create targeted heating zones. The controller adjusts heating intensity locally based on temperature sensor feedback, ensuring uniform temperature distribution throughout the storage medium while maintaining high storage capacity.
2Duration of action of moving object
If high-temperature thermal energy is stored for extended periods, then energy availability is improved, but heater lifetime decreases due to thermal stress
Solution Approach 1:
The heating system operates in periodic cycles rather than continuous high-temperature operation. The controller periodically activates and deactivates heaters based on stored energy levels and demand forecasts. This periodic heating allows thermal mass to retain energy during off-periods while giving heaters recovery time, reducing cumulative thermal stress and extending heater lifetime while maintaining energy availability.
Solution Approach 2:
The system incorporates thermal mass (brick stacks) that acts as a buffer between heaters and the external environment. This thermal cushioning absorbs and distributes thermal stress, protecting heaters from direct thermal shock. The brick material's high heat capacity allows it to store energy for extended periods while moderating temperature fluctuations that would otherwise damage heaters.
3Adaptability or versatility
If variable renewable energy is stored thermally, then fossil fuel dependency is reduced, but charging and discharging inefficiencies occur
Solution Approach 1:
The system dynamically adjusts operating parameters (heating temperature, heating rate, discharge temperature) based on the type of renewable energy input (solar, wind, excess grid power) and thermal demand requirements. By optimizing these parameters for different charging scenarios and discharge applications, the system maximizes round-trip efficiency while maintaining flexibility in integrating various renewable sources.
Solution Approach 2:
The controller continuously monitors temperature, energy storage levels, and power demand, adjusting heating and discharge operations in real-time. This feedback control optimizes charging efficiency by matching heating rates to available renewable power and maximizes discharging efficiency by delivering heat at temperatures matched to industrial process requirements, minimizing energy losses throughout the cycle.
4Quantity of substance
If thermal energy storage systems are designed for high capacity, then energy storage capability is improved, but system cost increases
Solution Approach 1:
The system uses inexpensive brick material as the primary thermal storage medium. Bricks are low-cost, readily available materials that can be easily replaced if needed. This approach achieves high storage capacity using cheap materials rather than expensive specialized thermal storage media, significantly reducing system cost while maintaining high energy storage capability.
Solution Approach 2:
The system combines multiple functions into integrated components: brick stacks serve as both structural support and thermal storage medium, heaters provide both heating and temperature sensing capabilities, and the controller manages both charging and discharging operations. This functional integration reduces the number of separate components needed, simplifying system design and reducing overall cost while achieving high storage capacity.
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
Enables efficient, cost-effective storage and delivery of high-temperature thermal energy, addressing thermal runaway and ensuring uniform temperature distribution, thereby extending heater lifetime and reducing operational costs.
Implementation Method 1
each of the heaters being connected to the input electricity
Implementation Method 2
storage of energy as sensible heat in tanks of liquid, including water, oils, and molten salts; sensible heat in solid media, including rock, sand, concrete and refractory materials
Implementation Method 3
latent heat in the change of phase between gaseous, liquid, and solid phases of metals, waxes, salts and water
Implementation Method 4
a blower for air circulation
Implementation Method 5
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 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. An array of bricks incorporating internal radiation cavities is directly heated by thermal radiation. The cavities facilitate rapid, uniform heating via reradiation. Heat delivery via flowing gas establishes a thermocline which maintains high outlet temperature throughout discharge. Gas flows through structured pathways within the array, delivering heat which may be used for processes including calcination, hydrogen electrolysis, steam generation, and thermal power generation and cogeneration. Groups of thermal storage arrays may be controlled and operated at high temperatures without thermal runaway via deep-discharge sequencing. Forecast-based control enables continuous, year-round heat supply using current and advance information of weather and VRE availability. High-voltage DC power conversion and distribution circuitry improves the efficiency of VRE power transfer into the system.