Granular Thermal Storage in Compressed Gas Energy Systems
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Solution Overview
Problem
There is a need for an efficient and cost-effective method to store electrical energy produced during non-peak periods for later use, particularly in conjunction with renewable energy sources, while minimizing infrastructure costs and environmental impact.
Innovation Solution
A compressed gas energy storage system that includes an accumulator configured to contain a layer of compressed gas atop a layer of liquid, a gas compressor/expander subsystem, and a thermal storage subsystem using granular heat transfer particles to efficiently manage thermal energy during charging and discharging cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If thermal energy is extracted and stored during charging, then system efficiency is improved, but device complexity increases
Solution Approach 1:
The thermal storage subsystem is merged with the existing compressed gas energy storage system by integrating heat transfer particles into the gas storage chamber. The particles are suspended in the compressed gas and serve dual purposes: thermal energy storage medium and gas cushioning agent, eliminating the need for separate thermal storage equipment.
Solution Approach 2:
The granular heat transfer particles perform multiple functions simultaneously: they store thermal energy through heat absorption and release, provide mechanical cushioning for the gas layer, and facilitate heat transfer between compression and expansion stages. This multi-functionality reduces overall system complexity while improving efficiency.
2Productivity
If granular heat transfer particles are used, then thermal energy management efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The system uses pneumatic principles by suspending granular heat transfer particles in the compressed gas phase. Gas flow carries the particles through the system, enabling automatic distribution and heat transfer without complex mechanical handling mechanisms, thus improving manufacturability despite the novel approach.
3Loss of energy
If thermal energy is re-introduced during discharging, then energy storage efficiency is improved, but infrastructure costs increase
Solution Approach 1:
The granular heat transfer particles automatically absorb thermal energy during gas compression and release it during expansion without requiring external control systems. The particles self-regulate thermal energy transfer based on the thermodynamic cycle, eliminating the need for active thermal management infrastructure.
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 efficiency by extracting and storing thermal energy during charging and re-introducing it during discharging, thereby optimizing energy storage and release processes while reducing the need for additional heat management systems.
Implementation Method 1
thermal energy may be extracted from the compressed gas exiting the gas compressor/expander subsystem at an exit temperature during a charging phase/process and stored in the thermal storage subsystem
Implementation Method 2
the temperature of the gas exiting the thermal storage subsystem may be reduced to a storage temperature that is less than the exit temperature. During an expansion process gas exiting the accumulator may pass through the thermal storage subsystem again before reaching the gas compressor/expander subsystem, whereby at least a portion of the thermal energy that was extracted from the compressed gas entering the accumulator may be re-introduced into the gas exiting the accumulator to raise the temperature of the gas from the storage temperature to a higher, exit temperature
Implementation Method 3
an accumulator configured for containing a layer of compressed gas atop a layer of liquid
Data Source
AI summary
A compressed air energy storage system may have an accumulator and a thermal storage subsystem having a cold storage chamber for containing a supply of granular heat transfer, a hot storage chamber and at least a first mixing chamber in the gas flow path and having an interior in which the compressed gas contacts the granular heat transfer particles at a mixing pressure that is greater than the cold storage pressure and the hot storage pressure and a conveying system operable to selectably move the granular heat transfer particles from the cold storage chamber, through the first mixing chamber and into the hot storage chamber, and vice versa.