Variable Pressure Vessel With Barrier-Separated Isothermal Compression

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Solution Overview

Problem

Current gas compression and expansion technologies in energy storage systems face efficiency losses due to direct contact between the gas and liquid, leading to gas dissolution, liquid loss, and reduced heat transfer efficiency.

Innovation Solution

A variable pressure vessel design featuring a liquid chamber and a gas chamber with a moveable barrier, where the gas chamber has a thermally conductive outer wall for improved heat transfer, separating the gas from the liquid piston and using a flexible enclosure to facilitate efficient volume displacement and heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If direct gas-liquid contact is used for heat transfer, then heat transfer efficiency is improved, but gas dissolution in liquid increases and compression/expansion efficiency decreases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidcompression/expansion efficiency
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

A flexible barrier is introduced as an intermediary between the gas and liquid, allowing heat transfer through the barrier while preventing direct contact between gas and liquid. This resolves the contradiction by enabling heat transfer without gas dissolution, maintaining both heat transfer efficiency and compression/expansion efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible barrier acts as a thin film that separates the gas chamber from the liquid chamber while maintaining thermal contact. This flexible membrane allows heat conduction while physically preventing gas-liquid mixing, thus improving reliability without sacrificing heat transfer efficiency.

Inventive Principle:
Principle #30Flexible shells and thin films

2Power

If liquid piston is used for gas compression/expansion, then mechanical work is transferred, but liquid loss occurs due to waves and surface motion

Engineering Contradiction:
Improvemechanical work transferVSAvoidliquid loss
Core Design Contradiction:
PowerVSLoss of substance

Solution Approach 1:

The flexible barrier serves as a mediator that transmits mechanical force from the liquid piston to the gas while preventing liquid from escaping with the gas. This allows effective power transfer while eliminating liquid loss through waves and surface motion.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible barrier acts as a containment film that moves with the liquid piston but prevents liquid ejection. This maintains the mechanical work transfer function while preventing substance loss.

Inventive Principle:
Principle #30Flexible shells and thin films

3Stress or pressure

If liquid is pumped into compression device to compress gas, then gas compression is achieved, but gas bubbles form during pressure decrease reducing efficiency

Engineering Contradiction:
Improvegas compressionVSAvoidcompression/expansion efficiency
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The flexible barrier acts as a permanent separator that prevents gas and liquid from mixing during pressure cycles. Gas bubbles cannot form because the liquid and gas are physically separated, maintaining compression/expansion efficiency while achieving effective gas compression.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible barrier creates a sealed interface that prevents gas bubble formation during pressure changes. The barrier maintains separation between phases throughout the compression and expansion cycles, eliminating the harmful foaming effect.

Inventive Principle:
Principle #30Flexible shells and thin films

4Loss of energy

If true isothermal compression is achieved, then energy loss is minimized, but infinite heat transfer area or time is required

Engineering Contradiction:
Improveenergy loss during compressionVSAvoidheat transfer area requirement
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The flexible barrier provides a large surface area for heat transfer in a compact configuration. The thin film structure allows efficient thermal conduction between gas and liquid without requiring infinite heat transfer area, enabling practical approximation of isothermal conditions.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The system uses the thermal properties of the liquid and the flexible barrier to facilitate heat transfer during compression and expansion. By changing the thermal parameters through the barrier material selection and liquid choice, near-isothermal conditions are achieved without infinite heat transfer area.

Inventive Principle:
Principle #35Parameter changes

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 design enhances heat transfer efficiency, minimizes gas dissolution in the liquid, and maintains isothermal conditions, thereby improving the overall efficiency of gas compression and expansion processes.

Implementation Method 1

The gas chamber has an outer wall wherein at least a portion of the outer wall is thermally conductive and allows heat to transfer therethrough

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

Movement of the moveable barrier between the liquid chamber and the gas chamber causes the volume in the liquid chamber and the volume in the gas chamber to displace each other

Methodology Applied
Scientific EffectPressure increase: Pressure Increase

Data Source

PatentEP3380774B1Variable pressure vessel
Publication Date: 2021.07.14 ISOCURRENT ENERGY
  • EP3380774B1 patent drawingFigure 1~2
  • EP3380774B1 patent drawingFigure 3~4
  • EP3380774B1 patent drawingFigure 5

AI summary

The present disclosure relates to a variable pressure vessel. The vessel includes a liquid chamber and a gas chamber and a moveable barrier therebetween. The vessel has a volume, a first stroke, and a second stroke. The liquid chamber and the gas chamber each have a variable volume that changes responsive to the first stroke and the second stroke. The gas chamber has an outer wall wherein at least a portion of the outer wall is thermally conductive and allows heat to transfer therethrough. Movement of the moveable barrier between the liquid chamber and the gas chamber causes the volume in the liquid chamber and the volume in the gas chamber to displace each other. The volume in the gas chamber plus the volume in the liquid chamber is generally constant and generally equals the volume in the variable pressure vessel.