Constant Volume Heating for Compressed Air Energy Storage

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Solution Overview

Problem

Compressed air energy storage (CAES) systems face inefficiencies due to the rejection of heat energy during compression, which is not fully utilized during expansion, leading to suboptimal energy recovery and the need for additional heating methods like gas burners to achieve realistic temperature conditions for energy retrieval.

Innovation Solution

A compressed gas energy storage and recovery system that implements heating at constant volume, using a heat exchanger between the stored compressed gas and a heat transfer fluid to increase the pressure and efficiency of energy recovery, allowing for better utilization of stored heat before expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If heat is rejected during compression in conventional CAES systems, then the system structure is simplified, but energy recovery efficiency deteriorates because the heat is not utilized

Engineering Contradiction:

Improveheat energy lossVSAvoidsystem structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent converts the previously rejected heat from compression into a useful resource by directing it to preheat the compressed air before expansion. The heat exchanger captures this waste heat and transfers it to the stored compressed air, transforming an energy loss into an energy recovery opportunity that improves overall system efficiency without requiring external fuel sources

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements preliminary heating of the compressed air using the heat exchanger before the air enters the expansion turbine. By preheating the air during the storage period rather than requiring reheating at the moment of expansion, the system prepares the air in advance to achieve optimal expansion conditions, improving energy recovery efficiency

Inventive Principle:

Principle #10Preliminary action

2Volume of stationary object

If compressed air is stored at ambient temperature and pressure, then storage volume is reduced, but energy recovery efficiency deteriorates due to unrealistic temperature conditions during expansion

Engineering Contradiction:

Improvestorage volumeVSAvoidenergy recovery efficiency

Core Design Contradiction:

Volume of stationary objectVSLoss of energy

Solution Approach 1:

The patent changes the temperature parameter of the compressed air before expansion by using the heat exchanger to heat the air to optimal temperatures. This parameter modification allows the air to expand efficiently in the turbine, converting thermal energy into mechanical work while maintaining compact storage volumes at ambient conditions

Inventive Principle:

Principle #35Parameter changes

3Temperature

If gas burners are used to reheat compressed air for expansion, then realistic temperature conditions are achieved, but energy loss increases due to fossil fuel consumption

Engineering Contradiction:

Improveair temperature before expansionVSAvoidfossil fuel energy loss

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The patent implements a self-service system where the heat exchanger uses the heat already present in the compressed air from the compression process to reheat the air before expansion. This self-contained thermal management system eliminates the need for external fossil fuel sources, allowing the system to achieve optimal expansion temperatures using its own stored thermal energy

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The heat exchanger acts as an intermediary device that transfers thermal energy from the compressed air to the air before expansion, replacing the need for gas burners. This intermediary mechanism enables temperature control and energy recovery without direct fossil fuel combustion, reducing energy losses and environmental impact

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This approach enhances the efficiency of energy recovery by increasing the pressure and temperature of the stored gas, enabling more effective energy generation from compressed gas expansion, thereby improving the overall efficiency of the CAES system.

Implementation Method 1

a heat exchange between the compressed gas and a heat transfer fluid

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

heater for heating the stored compressed gas at constant volume

Methodology Applied

Scientific EffectConstant volume heating: Heating

Implementation Method 3

the heat due to the compression is also stored in a heat storage system TES (Thermal Energy Storage)

Methodology Applied

Scientific EffectThermal energy storage: Thermal Energy Storage

Implementation Method 4

at least one compression device for compressing the gas

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 5

at least one device for expanding the compressed gas capable of generating energy

Methodology Applied

Scientific EffectExpansion:

Data Source

PatentUS10480409B2Compressed air energy storage and recovery system and method with constant volume heating

Publication Date: 2019.11.19 IFP ENERGIES NOUVELLES

AI summary

The invention is a compressed gas energy storage and recovery system and method, of AACAES type. The system and the method according to the invention heats at constant volume stored compressed gas to increase the pressure of the stored compressed gas.