Hybrid CAES Thermal Storage for Low-Carbon Air Expansion

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Solution Overview

Problem

Conventional compressed air energy storage (CAES) systems have a significant carbon footprint due to their reliance on fossil fuels, contributing to greenhouse gas emissions and environmental concerns.

Innovation Solution

A hybrid CAES system integrating diabatic and adiabatic CAES systems with a carbon-neutral thermal energy source, such as solar or geothermal, to enhance efficiency and reduce emissions, utilizing multiple compressor units, heat exchangers, and thermal storage to optimize energy transfer and storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If conventional CAES systems use fossil fuels for heating compressed air during power generation, then the system can maintain simplicity in thermal management, but carbon emissions increase significantly

Engineering Contradiction:
Improvecarbon emissionsVSAvoidthermal management system complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines diabatic and adiabatic CAES systems into a hybrid configuration, where the adiabatic portion stores compression heat in thermal energy storage units and uses it during expansion, while the diabatic portion handles excess or deficit thermal demands. This merging eliminates fossil fuel heating and achieves carbon-free operation while maintaining system feasibility through integrated thermal management.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces thermal energy storage units as intermediary components between compression and expansion processes. These storage units mediate thermal energy transfer, storing heat during compression and releasing it during expansion, thereby eliminating the need for fossil fuel-based heating systems and reducing carbon emissions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If a hybrid CAES system integrates carbon-neutral thermal energy sources and thermal storage, then energy efficiency and sustainability improve, but system complexity and initial investment costs increase

Engineering Contradiction:
Improveenergy efficiencyVSAvoidsystem configuration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the CAES system into distinct diabatic and adiabatic portions, each handling specific thermal management functions. The adiabatic portion with thermal storage handles base thermal demands, while the diabatic portion manages peak or variable demands. This segmentation improves overall energy efficiency by optimizing each segment's performance while maintaining manageable system complexity through modular architecture.

Inventive Principle:
Principle #1Segmentation

3Object-generated harmful factors

If thermal energy storage devices are integrated into the CAES system, then fossil fuel dependency is reduced and emissions decrease, but system cost and complexity increase

Engineering Contradiction:
Improvegreenhouse gas emissionsVSAvoidsystem implementation ease
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The thermal energy storage units serve multiple functions: storing compression heat, providing heating during expansion, and enabling flexible operation modes (adiabatic, diabatic, or hybrid). This multi-functionality reduces the need for separate specialized components, thereby reducing overall system complexity and improving ease of manufacture while achieving emission reduction goals.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 hybrid system achieves improved energy efficiency and reduced carbon emissions, making it more economically feasible and sustainable by leveraging carbon-neutral thermal energy sources and advanced thermal management techniques.

Implementation Method 1

Air compressed by the compressor is fed through a first heat exchanger that cools the compressed air

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

The heat that is recovered by the first heat exchanger is stored to a thermal storage device by circulating a heat transfer medium

Methodology Applied
Scientific EffectThermal energy storage: Thermal Energy Storage

Implementation Method 3

compressed air is realeased from the air storage unit and fed through a second heat exchanger that uses stored heat from the thermal storage device to heat the compressed air

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP3901437B1Hybrid compressed air energy storage system
Publication Date: 2024.12.25 SIEMENS ENERGY INC
  • EP3901437B1 patent drawingFigure 1
  • EP3901437B1 patent drawingFigure 2
  • EP3901437B1 patent drawingFigure 3

AI summary

A hybrid compressed air energy storage system is provided. A heat exchanger 114 extracts thermal energy from a compressed air to generate a cooled compressed air stored in an air storage reservoir 120, e.g., a cavern. A heat exchanger 124 transfers thermal energy generated by a carbon-neutral thermal energy source 130 to cooled compressed air conveyed from reservoir 120 to generate a heated compressed air. An expander 140 is solely responsive to the heated compressed air by heat exchanger 124 to produce power and generate an expanded air. Expander 140 being solely responsive to heated compressed air by heat exchanger 124 is effective to reduce a temperature of the expanded air by expander 140, and thus a transfer of thermal energy from an expanded exhaust gas received by a recuperator 146 (used to heat the expanded air by the first expander) is effective for reducing waste of thermal energy in exhaust gas cooled by recuperator 146.