Elastomeric Accumulator Strain Energy Storage

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Solution Overview

Problem

Conventional hydraulic accumulators face inefficiency due to heat losses and gas diffusion issues, making them heavy, costly to maintain, and inefficient for energy storage in compact spaces.

Innovation Solution

The use of multiple bladders in a fluid-based system, where the low-pressure reservoir is integrated with the high-pressure accumulator, allowing for efficient energy storage by utilizing differential pressure across bladders to prevent gas diffusion and reduce weight and space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If gas is used for energy storage in conventional accumulators, then gravimetric energy density is improved, but gas diffusion through the bladder into the hydraulic fluid occurs causing high maintenance costs

Engineering Contradiction:

Improvegravimetric energy densityVSAvoidgas diffusion into fluid

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The invention extracts and eliminates the gas component from the energy storage mechanism. Instead of using compressed gas in a bladder, the system uses a mechanical spring piston mechanism where the spring stores energy mechanically. This removes the source of gas diffusion problems entirely while maintaining energy storage capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the gas-based energy storage system with a purely mechanical spring-piston system. The spring mechanism provides the same energy storage function without requiring gas, thereby substituting a problematic system with a reliable mechanical alternative that eliminates gas-fluid interaction issues.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Use of energy by moving object

If gas bladder accumulators are used for energy storage, then gravimetric energy density is improved, but heat losses reduce efficiency

Engineering Contradiction:

Improvegravimetric energy densityVSAvoidheat losses

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The invention replaces the gas compression/expansion process with direct mechanical spring compression and expansion. This mechanical system avoids the thermal losses inherent in gas processes, as the spring stores and releases energy isothermally without the heat transfer problems that plague gas-based accumulators.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If conventional accumulator designs are used, then energy storage capacity is achieved, but device weight and volume are excessive

Engineering Contradiction:

Improveenergy storage capacityVSAvoidaccumulator weight

Core Design Contradiction:

Quantity of substanceVSWeight of moving object

Solution Approach 1:

The invention changes the fundamental operating parameters by using a mechanical spring system instead of gas compression. This allows for a more compact and lighter design because the spring mechanism can store the same amount of energy in a smaller, lighter package compared to gas-filled bladders and heavy containment structures required for gas accumulators.

Inventive Principle:

Principle #35Parameter changes

4Quantity of substance

If conventional accumulator designs are used, then energy storage capacity is achieved, but device weight and volume are excessive

Engineering Contradiction:

Improveenergy storage capacityVSAvoidaccumulator volume

Core Design Contradiction:

Quantity of substanceVSVolume of stationary object

Solution Approach 1:

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 achieves a volumetrically and gravimetrically dense energy storage solution, reducing maintenance costs and improving efficiency by storing energy through strain in elastomeric materials without significant heat loss, while allowing for increased pressure and volume without compromising bladder material strength.

Implementation Method 1

storing strain energy in a fluid based system

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9010101B2Multiple accumulator systems and methods of use thereof

Publication Date: 2015.04.21 VANDERBILT UNIV

AI summary

The invention is an accumulator system in which multiple elastomeric accumulators are attached in series or parallel in order to generate total differential pressure in excess of that generated in a non-series system. Also disclosed is a “stacked” accumulator system. The system stores energy when the accumulators deform from their original shape in response to the flow of a pressurized fluid. The stored energy is available for use when the fluid is released from the accumulators and the accumulators return to their original shape.